Wednesday, July 29, 2009

Effectiveness of Oseltamivir in Preventing Influenza in Household Contacts

JAMA. 2001;285:748-754.

A Randomized Controlled Trial

Robert Welliver, MD; Arnold S. Monto, MD; Otmar Carewicz, MD; Edwig Schatteman, MD; Michael Hassman, DO; James Hedrick, MD; Helen C. Jackson, PhD; Les Huson, PhD;Penelope Ward, MD; John S. Oxford, PhD; for the Oseltamivir Post Exposure Prophylaxis Investigator Group


Context Influenza virus is easily spread among the household contacts of an infected person, and prevention of influenza in household contacts can control spread of influenza in thecommunity.

Objective To investigate the efficacy of oseltamivir in preventing spread of influenza to household contacts of influenza-infected index cases (ICs).

Design and Setting Randomized, double-blind, placebo-controlled study conducted at 76 centers in North America and Europe during the winter of 1998-1999.

Participants Three hundred seventy-seven ICs, 163 (43%) of whom had laboratory-confirmed influenza infection, and 955 household contacts (aged =" border="0">12 years) of all ICs (415 contactsof influenza-positive ICs).

Interventions Household contacts were randomly assigned by household cluster to take 75 mg of oseltamivir (n = 493) or placebo (n = 462) once daily for 7 days within 48 hours ofsymptom onset in the IC. The ICs did not receive antiviral treatment.

Main Outcome Measure Clinical influenza in contacts of influenza-positive ICs, confirmed in a laboratory by detection of virus shedding in nose and throat swabs or a 4-fold or greaterincrease in influenza-specific serum antibody titer between baseline and convalescent serum samples.

Results In contacts of an influenza-positive IC, the overall protective efficacy of oseltamivir against clinical influenza was 89% for individuals (95% confidence interval [CI], 67%-97%;P<.001) and 84% for households (95% CI, 49%-95%; P<.001). In contacts of all ICs, oseltamivir also significantly reduced incidence of clinical influenza, with 89% protective efficacy(95% CI, 71%-96%; P<.001). Viral shedding was inhibited in contacts taking oseltamivir, with 84% protective efficacy (95% CI, 57%-95%; P<.001). All virus isolates from oseltamivir recipients retained sensitivity to the active metabolite. Oseltamivir was well tolerated; gastrointestinal tract effects were reported with similar frequency in oseltamivir (9.3%) and placebo (7.2%) recipients.

Conclusion In our sample, postexposure prophylaxis with oseltamivir, 75 mg once daily for 7 days, protected close contacts of influenza-infected persons against influenza illness, prevented outbreaks within households, and was well tolerated.

Who will get the vaccine first?

it's hard to come up with a clear answer. The US, UK and other governments have promised that people at greatest risk from the virus will be vaccinated first. But it is not yet known if this means people who are obese or pregnant – so far the clearest risk factors.

Who should get the swine flu vaccine?

One of Labour's favourite mantras is that being in government is about making the tough decisions. But when it comes to swine flu, a series of choices is approaching that may prove a matter of life and death.
The problem is this. The Government has purchased enough vaccine against this strain of swine flu (H1N1) to treat the entire population – 61 million people – at a cost of £155.4 million. However, by the end of the year, when the second wave of the pandemic is expected to be at its height, we will only have received half of the order. So officials have a decision to make: who gets the vaccine first?

Robert Colvile reveals the ethical dilemma facing the Government over the coming months.

According to the World Health Organisation, frontline health workers are the top priority, followed by the most vulnerable groups. In a paper published yesterday on The Lancet website, researchers urged that pregnant women should be prioritised because, according to reports from the US, they have higher than expected death rates from swine flu. The very young and those with existing medical conditions will also be high up the list.
But the key question – which is said to be preoccupying civil servants at the Department of Health, and their Secretary of State, Andy Burnham – is who comes next. Pensioners are normally a priority for flu vaccines. But they do not seem to be at quite as much risk from H1N1: rates of infection and hospitalisation are surprisingly low, perhaps because of residual immunity to similar strains in the 1950s, perhaps because it is easier to avoid infection if you don't have to go to work.
This leads us into the kind of value judgments that make us uncomfortable. Some ethicists argue that the fairest means of distribution, after taking care of the most vulnerable, is a lottery. Professor Robert Dingwall, who sits on the Committee on Ethical Aspects of Pandemic Influenza, points out that it is illegal to discriminate in terms of age, or usefulness to society. In other words, a healthy pensioner cannot claim priority over a healthy teenager, unless there is evidence that pensioners are at greater risk – but nor can the authorities choose to vaccinate that teenager on the grounds that he has a longer life ahead, or will make a greater contribution to the economy.
There are also possible problems with the vaccine. In 1976, an outbreak of another strain of swine flu at a US military base prompted a panicked attempt to immunise the entire American population. Before the programme was abandoned, 40 million people had received the jab – several hundred of whom developed Guillain-BarrĂ© syndrome, a rare neurological condition that causes muscle weakness or paralysis. As a result, more than 30 people died, compared to just one soldier killed by swine flu.
The risk of such side effects is less today, given that the "template" for the new vaccine has been tested using a different strain. There is also more reason to be alarmed, given the rapid spread of the outbreak. Yet the World Health Organisation has warned of the dangers of rushing vaccines to market. Already, the British and US governments have had to absolve manufacturers from liability. And even if there are no undiscovered side effects, what happens if – as with MMR – a belief arises that a safe vaccine is risky? If a parent refuses to vaccinate their child, should the state have the right to enforce it in order to protect the child, or others they might infect?
These questions have no easy answer – but the Government must address them. There have already been deaths from swine flu. But the decisions made in the coming weeks about who gets the vaccine, and in what order, may save – or endanger – many more. We can expect a few more sleepless nights in the corridors of power.

Tuesday, July 28, 2009

Tamiflu for Prevention of Influenza

Protect Family Members – Take Action Immediately

TAMIFLU is indicated for the treatment of uncomplicated acute illness due to influenza infection in patients 1 year and older who have been symptomatic for no more than 2 days. TAMIFLU is indicated for prophylaxis of influenza in patients 1 year and older. TAMIFLU is not a substitute for early and annual influenza vaccination. 1

  • Vaccination is the first line of defense against influenza. According to the CDC, antiviral medications can be effective for the prevention of influenza. 3

Protect Adults from Influenza Infection

TAMIFLU Helps Prevent Flu Transmission in Adults 1

Number of household contacts aged ≥12 years=405

  • The primary efficacy endpoint was the proportion of contacts of an influenza-positive index case with laboratory-confirmed clinical influenza 11

A cluster-randomized, double-blind, placebo-controlled study conducted at 76 centers in North America and Europe during the winter of 1998-1999 that involved 377 index cases: 43% with laboratory-confirmed influenza infection. 11

Protect Children from Influenza Infection

TAMIFLU Provides Protective Efficacy Against Flu in Children 1 to 12 Years Old 1

  • Primary efficacy variable was the percentage of households with at least 1 secondary case of laboratory-confirmed influenza illness during the 10-day period after the start of treatment in the index case(s) 8

A prospective, open-label, randomized, parallel-group trial conducted in Europe and North America during the 2000-2001 influenza season with a total of 812 participants aged ≥1 year. Household contacts of index cases received postexposure prophylaxis with oseltamivir for 10 days or treatment at the time of developing illness (expectant treatment) during the postexposure period. All index cases received oseltamivir treatment for 5 days. 8

TAMIFLU is indicated for prophylaxis of influenza patients 1 year and older. TAMIFLU is not a substitute for early and annual vaccination.

Track the flu. Help protect your patients by knowing when influenza is in your area.

Learn about TAMIFLU side effects and safety.

Influenza Resources

Download information about treatment and prevention of influenza:

Browse other resources for Diagnosing,
Managing and Tracking Influenza

Be Prepared for Flu Season

Help manage the impact of influenza season on your practice.

Review Office Preparation Tips

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Swine Flu Antiviral Protection

Recommended by Crabsallover!! Note: / / are registered with Royal Pharmaceutical Society of Great Britain.

Swine Flu Antiviral Protection

If you wish to protect yourself and your family from the threat of Swine Flu, you can purchase antiviral medication ahead of developing any symptoms.
Healthcare Connections is a private, bona fide, accredited organisation that has been working on pandemic planning for over five years and holds the UK's largest supply of antiviral medication outside of the Government.
You can buy the Antiviral medication online now to store safely in your medicine cabinetin order to give yourself peace of mind. The medication is a prescribed drug and therefore you do need to complete an online medical questionnaire. Our team of qualified physicians then verifies each questionnaire before we ship the medication to your door. The cost is £49 + vat. All of our medication is stored in our secure, climate controlled, pharmaceutical warehouse.

A/H1N1 influenza virus: the basics by Geoff Watts

Published 24 July 2009, doi:10.1136/bmj.b3046
Cite this as: BMJ 2009;339:b3046


Pandemic flu

A/H1N1 influenza virus: the basics

Geoff Watts, freelance journalist

1 London

Do you know your H1N1s from your H2N2s? Geoff Watts explains the basic science of the influenza virus

The influenza virus has three genera: A, B, and C. All can infect humans, but only A is responsible for illness on the pandemic scale. So it’s A that attracts attention. The virus comes in many different guises.

The version currently besetting us—swine flu—is more properly called H1N1 2009, the letters referring to two all important glycoproteins dotted over the surface of the viral envelope. H stands for haemagglutinin: a molecule that anchors the virus to any cell it seeks to enter. No anchorage, no entry. Given the key role played by haemagglutinin, it’s no surprise that this is the antigen used to prepare antifluvaccines. And then there’s N, short for neuraminidase. Accounting for up to a quarter of the viral surface protein, this is an enzyme that helps invading viruses to digest their way through mucous secretions as they approach the host cell, and later it assists in the release of newly synthesised virus.Neuraminidase too is tactically important to medicine, because the antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza), work by inhibiting it.


And so to variability. The H molecule comes not in just one form but in no fewer than 16. Wasteful? Extravagant? Not at all. All H variants retain the capacity to attach the virus to its prey, but each is sufficiently different from the others to fool the host’s immune defences. Neuraminidase also comes in different structural subtypes—nine in all—which can be found in different combinations with haemagglutinin. Although we’re currently plagued by H1N1, it was H2N2 that caused the 1957 outbreak.

Nor is this the full extent of viral variability. Frequent mutation within the viral genome causes single amino acid substitutions in its proteins, notably in the make up of haemagglutinin. Most of these alterations are concentrated in regions of the molecule that form a set of outwardly projecting loops. Changes in these loops have little effect on haemagglutinin’s core function; but the loops happen to be the parts of the molecule on which the host’s immune system relies to recognise the identity of its attacker. So although a flood of minor modifications are neither here nor there to the virus, they can confuse the host—which is perpetually running to catch up. The greater the change in the virus, of course, the less the chance that any existing host immunity will be effective.

"Shift" and "drift"

These processes of antigenic change are referred to as "shift" and "drift"—a distinction that causes some confusion. "Drift" has been used to describe the incremental selection of minor mutations leading to slow changes of the virus over time. "Shift," by contrast, was originally reserved for the more substantial subtype changes of the H1 to H2 variety. Such categorisation is no longer meaningful. This year’s virus is an H1N1 variant. So was last year’s; no change of subtype. But over the same period more than a quarter of the amino acids in its haemagglutinin protein have "drifted." Substantial change, by any measure; a drift with as much or more impact than a shift. Better to avoid the terms. More to the point, the extent of this antigenic change has confounded earlier hopes that because the 2008 and the 2009 viruses are both H1N1 variants, last year’s antiflu vaccine would confer some benefit. No such luck.

Evolutionary dances

The evolutionary pressures that serve to keep the antigenic carousel spinning are aided by the unusual structure of the influenza virus’s genome. The RNA of which it’s made comes in eight separate segments which, because they are independent of one another, can undergo what’s called genetic reassortment. If two viruses infect the same cell at the same time, they may exchange genes during replication. The new virus particles will then carry a combination of genetic material from both parents. And even that’s not the end of it. Suppose a cell is simultaneously invaded by strains of virus that normally colonise different host species: birds, say, as well as humans. Precisely this is presumed to have happened in 1957 and 1968. The influenza types responsible for those outbreaks arose through the exchange of genes between avian and human viruses. The fact that flu viruses can move—albeit not easily—between different vertebrate hosts gives them a vastly enlarged reservoir in which to perform their evolutionary dances. They have the opportunity to conjure up new steps which, even if they fail to cut the mustard in a pig, might play well in a man.

Taking all these mechanisms together, it’s clear that the influenza virus has an impressive clutch of shots in its locker. So are there no boundaries to this versatile organism’s flexibility and adaptability? Fortunately there are. Virologists at the US National Institute of Allergy and Infectious Diseases(NIAID) have recently reminded us that only three combinations of haemagglutinin and neuraminidase—H1N1, H2N2, and H3N2—have been found in humans.1 This, they suggest, implies some limit to the flu virus’s capacity to adapt to its hosts

Also limited is its capacity to switch host species. One microbiologist who’s published a thoughtful commentary on recent developments in influenza is microbiologist William Gallaher, emeritus professor at Louisiana State University Health Sciences Center.2 Accidental crossovers from animals to humans happen all the time, he points out, "But usually they don’t transmit to other human beings. They come to a dead end. Take the H5N1 avian influenza. That’s crossed over to human beings hundreds of times just in the past 10 years, but it’s never caused a subsequent infection." Only a few crossovers, mostly from swine, have ever led to widespread infection in humans—notably, of course, in 1918. And precisely because successful crossovers are rare they’re hard to study. Little is known about the process or the circumstances under which crossover is most likely to occur. Now, in 2009, it seems to have happened again; but all that can be said is that its success seems not to have depended on the acquisition of one magic gene combination.

The three NIAID virologists point out that it’s possible to infer the recent evolutionary history of H1N1.1The current variant, they say, is the descendant of two unrelated swine viruses, one of them a derivative of the 1918 human microbe. "Ever since 1918 this tenacious virus has drawn on a bag of evolutionary tricks to survive in one form or another, in both humans and pigs, and to spawn a host of novel progeny viruses with novel gene constellations."

But what do the make up of the virus and its evolutionary history say about its future? Regretfully, says Gallaher, not a great deal. "I can’t tell you why this [current outbreak] didn’t happen in Wisconsin in 1998 or in Maryland in 2005 because those viruses look similar enough. Why did it take off in Mexico when it didn’t take off then?" But, he adds, maybe if we look closely enough we will eventually find something of sound predictive value. Indeed, as the microbiologists Taia Wang and Peter Palese of New York’s Mount Sinai School of Medicine have pointed out, a coding sequence for the smallest of the viral proteins, PB1-F2, seems to be one marker of pathogenicity.3 It was present in the strains responsible for the 1918, 1957, and 1968 pandemics.Encouragingly, the current version of H1N1 does not carry it.

Reasons for optimism

In addition, other reasons allow us to be optimistic. As distinct from 1918, we live in an age of antibiotics and antivirals that can prevent the onset of pneumonia. And the virus too may be learning to behave in a more "civilised" manner. Morens and colleagues point out that successive pandemics seem to be decreasing in severity.1 This diminution, they suggest, reflects evolutionary "choices" that favour optimal transmissibility with minimal pathogenicity: "a virus that kills its host or sends them to bed is not optimally transmissible."

In the meantime William Gallaher, who has a "significant cardiopulmonary disability" and who has had three encounters with H1N1, remains personally wary of it. "I don’t take this virus for granted. It can kill you. I’ve been very sick with it several times in my life, and I know what a real enemy it can be. If it spread more widely, even in its current form, which is not highly virulent, it could kill a bunch of people." As he likes to point out, forecasting viral behaviour remains more uncertain even than trying to predict earthquakes.

Cite this as: BMJ 2009;339:b3046

Competing interests: None declared.


  1. Morens DM, Taubenberger JK, Fauci AS. The persistent legacy of the 1918 influenza virus. N Engl J Med 2009;361:225-9.[Free Full Text]
  2. Gallaher WR. Towards a sane and rational approach to management of influenza H1N1 2009. Virol J 2009, doi:10.1186/1743-422X-6-51.
  3. Wang T, Palese, P. Unravelling the mystery of swine influenza virus. Cell2009;137:983-5.[CrossRef][Web of Science][Medline]

Swine flu basics - science

A recent article in the British Medical Journal discusses the basics of the Pandemic (H1N1) 2009 virus, including how it differs from ordinary seasonal flu and how mutations lead to these new strains.

Here we discuss these points in the context of other basic facts about the H1N1 strain that is causing the current global pandemic.

Influenza type A

There are three main types (genera) of influenza virus: type A, type B and type C. Type A is the most noteworthy as it is responsible for regular outbreaks of disease in humans. This virus also infects pigs, horses and other animals and its natural host is the wild bird. In fact, only type A can infect birds. Type B viruses also cause human infection, but mutate slowly and are less common. Influenza type C causes only mild respiratory symptoms and has not been linked to serious human epidemics.

Influenza A is further classified by the nature of some of the proteins that are embedded in its outer layer. Haemagglutinin (H) and neuraminidase (N) are two proteins with important roles in how effectively the virus can invade a host. Influenza A can have a number of different types of haemagglutinin but for human infections, H1, H2 and H3 are important. There are also a number of different neuraminidases, of which N1 or N2 are usually found in combination with one of the above H molecules.

Viruses are named after which complement of H and N are in their outer layer. For example, swine flu is a new H1N1 virus and therefore carries the proteins haemagglutinin 1 and neuraminidase 1. Although other H1N1 viruses have circulated before, this new strain differs substantially from previous strains.

What are the concerns with swine flu?

Swine flu is a new H1N1 virus. This means that before this year’s outbreak, this exact type of virus has never before circulated in humans. This is of concern at it means that the general population is not immune to the virus, and so it has the potential for a greater impact than ordinary seasonal influenza.

H1N1 viruses are fairly uncommon and every year H1N1 adds to the burden of disease associated with seasonal influenza. However, viruses change regularly, creating new strains. Even small differences in viral structure can affect the way a host responds to an infection. This is why flu vaccines need to be updated every year to keep up with these changes.

How do viruses change?

Viruses change by mutating in several different ways. Sometimes spontaneous mutations can happen in the genes of a virus. Alternatively, a process called reassortment can occur, when different strains of flu virus share genes with each other in the same host to make a new strain.

‘Drift versus shift’

The term ‘antigenic drift’ is sometimes used to explain the small mutations in a virus that happen over time. These lead to a gradual evolution of the virus and population immunity is more or less able to keep up with these changes. ‘Antigenic shift’ on the other hand explains bigger mutations that suddenly produce a new virus. These new viruses are usually responsible for serious outbreaks and pandemics because populations have little or no immunity to them.

The BMJ article explains that small changes in the structure of the genes responsible for haemagglutinin may alter the way the body responds. The origin of the new H1N1 strain currently circulating has been described by three virologists as a descendant of two unrelated pig viruses.

What will the impact of swine flu be?

It is difficult to predict the impact of swine flu. So far, most infected people recover after a period of illness that is similar to seasonal flu. However, in people with comorbidities (e.g. lung disease, heart disease, kidney disease and diabetes) or the elderly and very young, the infection can be more severe.

To ensure that services can cope with future demand, scientists work hard to predict how the virus may spread and how it will affect people.

Reasons to be optimistic

Geoff Watts, the author of the BMJ article, points out several important reasons to be optimistic about the current flu pandemic:

  • Antiviral treatments are available that can limit the spread of infection and reduce the impact of swine flu on populations.
  • A vaccine will soon be available and rolled out. The most vulnerable groups will most likely receive it first, both protecting them from potentially serious illness and helping to halt the spread of infection.
  • There is some evidence that pandemics are becoming less severe over time, although this is difficult to prove given that management of outbreaks is also improving with time and experience.

Links to the science

A/H1N1 influenza virus: the basics. BMJ 2009, July 24

Further reading

Influenza viruses. Types, Subtypes, and Strains. Centers for Disease Control and Prevention 2009

The Pandemic Flu Game

The Camden Flu Pandemic Game was originally developed by Camden Primary Care Trust using NHS resources in partnership with Camden Council; it was designed as a training resource for their own staff and to help managers of local businesses and voluntary organisations develop their own business continuity plans. This version has been adapted by the Department of Health specifically for use in GP Practices.

The Flu Pandemic Game may be copied, adapted and used by any UK organisation for business continuity training or business continuity planning purposes. The Flu Pandemic Game may not be offered for sale or trade in whole or in part. It may not be copied into another document either in whole or in part unless a condition containing this condition is imposed on any subsequent user.

The Flu pandemic game - A business continuity training resource for GP practices

29 June 2009

Tom Nolan: Prescribing antivirals - is beyond 48 hours too late?

22 Jul, 09 | by julietwalker

After Monday’s statement to the House of Commons from Andy Burnham (you can watch all ten hours of the commons session here), the RCGP emailed members to summarise this and other developments.

One question raised by the e-mail is over the recommendation for GPs to prescribe antivirals if the patient has been symptomatic for fewer than seven days. That’s five days longer than was recommended in the old NICE guidelines for seasonal influenza. So why the change? Here’s the response from the Department of Health.

“The decision…was based on accumulating evidence that tamiflu can provide benefit for severe or prolonged cases, whose course of disease is likely to be longer than the 3-4 days in the healthy community cases which were the basis of the licensing process.

“Applications for licensing have to include large ‘pivotal’ studies to demonstrate the efficacy and safety of a medicine. In the community, where most cases last around 4.6-5 days, the medicine had to be given very early, in order to demonstrate any significant shortening of the illness.

“Older patients, those already severely ill and those predisposed to severe illness, however, appear to benefit from treatment started later than this. The Department of Health SAGE (Scientific Advisory Committee for Emergencies) examined current evidence and supported a lengthening of the time-window for treatment.”

Based on the answer given in the last of these paragraphs, couldn’t you argue that the window only be extended beyond 48 hours to those who are “older”, “already severely ill” and “predisposed to illness”? The stockpile of antivirals may be large, but unnecessary prescribing only increases the likelihood of resistance and puts greater strain on services.

Tom Nolan is the clinical community editor of doc2doc, the BMJ’s professional networking community.



Household close contacts of confirmed or probable cases warrant prophylaxis with oseltamivir or zanamivir if the contacts are at high risk for complications from influenza. Healthcare workers who did not use appropriate personal protective equipment during close contact with ill confirmed, probable, or suspected cases during the case's infectious period also warrant consideration of prophylaxis. source: BMJ Best Practice.

Prevent flu with Tamiflu

I've decided to take Tamiflu as a preventative measure (prophylaxis) should one of our family or close friends, that we are in close contact with, gets Swine Flu. I've discussed this Tamiflu strategy with my wife but she actually got quite shirty with me saying I'm becoming too bossy!. Its a shame because she will suffer, as will our small business, if she gets Swine flu.

Monday, July 27, 2009

Regulated Tamiflu

link for pdf:

Tamiflu Capsules 75mg - patient information leaflet

Always take Tamiflu exactly as your doctor has told you. You should check with your doctor or
pharmacist if you are not sure.
Take Tamiflu as soon as you get the prescription as this will help to slow the spread of the influenza
virus in the body.
Swallow Tamiflu capsules whole with water. Do not break or chew Tamiflu capsules.
The usual dose is as follows:
Adolescents (13 to 17 years of age) and adults: For treatment of influenza take one capsule as soon as
you get the prescription and then take one capsule twice a day (usually it is convenient to take one in
the morning and one in the evening for five days). It is important to complete the whole 5 day course,
even if you start to feel better quickly.
30 mg and 45 mg capsules can be used by adults and adolescents as an alternative to 75 mg capsules.
Infants 1 year of age and older and children 2 to 12 years of age: Tamiflu oral suspension or 30 mg
and 45 mg capsules can be used instead.
Children weighing more than 40 kg and who can swallow capsules may take Tamiflu 75 mg capsules
twice daily for 5 days.
Tamiflu can also be used for prevention of influenza following exposure to an infected individual,
such as family members.
Adolescents (13 to 17 years of age) and adults: When used to prevent influenza following exposure to
an infected individual, such as family members, Tamiflu should be taken once daily for 10 days. It is
best to take this dose in the mornings with breakfast.
Infants 1 year of age and older and children 2 to 12 years of age: Tamiflu oral suspension or 30 mg
and 45 mg capsules can be used instead.
Children weighing more than 40 kg and can swallow capsules may take Tamiflu 75 mg capsules once
daily for 10 days.
Your doctor will recommend the length of time to continue taking Tamiflu, if it is prescribed to
prevent influenza.

Swine Flu FAQ - NHS


What is swine flu?

Swine influenza is a disease in pigs. The virus currently transmitting among people is now generally referred to as swine flu, although the origin of the disease is still under investigation. There is no evidence of this strain of the disease circulating in pigs in the UK.

There are regular outbreaks of swine influenza in pigs worldwide. It does not normally infect humans, although this occasionally does occur - usually in people who have had close contact with pigs.

Swine influenza viruses are usually of the H1N1 subtype. The swine flu that has spread to humans is a version of this virus.

Why is swine flu affecting humans?

Because the swine flu virus has mutated (changed) and is now able to infect humans and transmit between them.

Which people are most vulnerable from swine flu?

Those who are more at risk from becoming seriously ill with swine flu are:

  • people with chronic lung disease, including people who have had drug treatment for their asthma within the past three years,
  • people with chronic heart disease,
  • people with chronic kidney disease,
  • people with chronic liver disease,
  • people with chronic neurological disease (neurological disorders include motor neurone disease, Parkinson's disease and multiple sclerosis),
  • people with suppressed immune systems (whether caused by disease or treatment),
  • people with diabetes,
  • pregnant women,
  • people aged 65 years and older, and
  • young children under five years old.

For specific advice on antiviral treatment for these groups, go to People with long-term conditions, Pregnancy and children andOlder people.

How is swine flu infection diagnosed?

There is now a new self-care service, called the National Pandemic Flu Service, which allows people to check their condition online or over the telephone (0800 1 513 100 or textphone 0800 1 513 200) and obtain antiviral medication if swine flu is confirmed.

The following people should call their GP directly for an assessment of their symptoms and a diagnosis:

  • those with a serious underlying illness,
  • pregnant women,
  • those who have a sick child under one year of age,
  • those with a condition that suddenly gets much worse, or
  • those with a condition that is still getting worse after seven days (five for a child).

For more information, go to the Flu Service - Q&A.

Is the new swine flu virus contagious?

The Health Protection Agency (HPA) says the new swine flu virus is highly contagious and is spreading from person to person.

Swine flu spreads in the same way as ordinary colds and flu. The virus is spread through the droplets that come out of the nose or mouth when someone coughs or sneezes.

If someone coughs or sneezes and they do not cover it, those droplets can spread about one metre (3ft). If you are very close to the person you might breathe them in.

Or, if someone coughs or sneezes into their hand, those droplets and the virus within them are easily transferred to surfaces that the person touches, such as door handles, hand rails, telephones and keyboards. If you touch these surfaces and touch your face, the virus can enter your system, and you can become infected.

See Causes for more information

How long does the virus live on surfaces?

The flu virus can live on a hard surface for up to 24 hours, and a soft surface for around 20 minutes.

What is the incubation period for swine flu?

According to the Health Protection Agency, the incubation period for swine flu (time between infection and appearance of symptoms) can be up to seven days, but is most likely to be between two and five days. It is, however, too early to be able to provide details on virus characteristics, including incubation period, with absolute certainty at this time.

When are people most infectious?

People are most infectious to others soon after they develop symptoms, although they continue to shed the virus (for example, in coughs and sneezes) for up to five days (seven days in children). People become less infectious as their symptoms subside, and once their symptoms are gone, they are no longer considered infectious to others.

How quickly is swine flu spreading?

Swine flu is now widespread in the UK and spreading rapidly. The number of new cases in the UK is doubling every seven days. Most of these are because people are catching swine flu in their local community and not as the result of foreign travel.

Go to the Latest on swine flu for a current list of all the countries affected by swine flu.

Should I avoid contact with people suspected of having swine flu?

All suspected cases who have swine flu symptoms will have been asked to self-isolate at home and restrict their contact with people. The vast majority of people should go about their normal activities, including going to school or work. This includes children who attend a school with a confirmed case of swine flu.

There is no need on risk grounds to avoid contact with people who might simply have come into contact with those having the illness, such as the parents of children at schools with a confirmed case but who are not themselves ill.

How dangerous is it?

It is difficult to judge this at the moment. While there have been deaths, symptoms exhibited by most infected people have not been severe.

It appears that early doses of antiviral medicines such as Tamiflu are effective in helping people to recover. In the UK we have enough antivirals to treat half the population if they were to become ill. Also, orders of Tamiflu have been placed to increase UK supplies to 50m doses, enough to treat 80% of the population.

What are the symptoms of swine flu?

The symptoms of swine flu in people are expected to be similar to the symptoms of regular human seasonal flu and include fever (a high body temperature of 38C/100.4F or over), fatigue, lack of appetite and coughing (see Symptoms). Some people with swine flu have also reported runny nose, sore throat, nausea, vomiting and diarrhoea.

How long are symptoms expected to last?

As with any sort of influenza, the severity and duration of symptoms will vary depending on treatment and individual circumstances. Most cases reported in the UK to date have been relatively mild, with those affected starting to recover within a week.

How does swine flu cause death?

Like any other type of flu, people can die from swine flu if they develop complications, like pneumonia.

Has the swine flu virus developed resistance to Tamiflu?

Not at the moment. Routine sampling of the virus in the UK has shown that there is currently no resistance to either Tamiflu or Relenza.

One flu H1N1 virus strain showing Tamiflu resistance was reported in a patient in Denmark who had received treatment - however, Tamiflu resistance in individual patients does occur in a low percentage of cases and is of limited public significance. The Health Protection Agency is monitoring whether such viruses are being transmitted from person to person.

Will the swine flu virus become resistant to antivirals in the future?

It is possible. The virus may mutate (change) and become less susceptible or resistant to the antiviral drug, and then spread from person to person. If the virus does develop resistance, it’s more likely to be to Tamiflu, the main antiviral treatment. If this happens, the government has a stockpile of Relenza that could be used instead.

Should we expect a more severe second wave of the pandemic in the winter?

Features of previous flu pandemics suggest that the current viral strain will become even more widespread in the autumn or winter, causing more illness and death. It is possible that the virus will mutate (change) into a more potent strain.

Should I go to work or school if I have been in contact with someone who I know has swine flu?

Yes, as long as you do not have flu-like symptoms. If you are feeling well, you should go about your normal activities, including going to school or work.

It can take up to seven days (normally two to five days) after infection for swine flu symptoms to develop. If you develop symptoms, stay at home and follow the general advice (see What should I do if I think I’m infected?).

Is it possible to catch swine flu twice?

Yes, because the virus can mutate (change). If you become infected with the swine flu virus, your body produces antibodies against it, which will recognise and fight off the virus if the body ever encounters it again. However, if the virus mutates, your immune system may not recognise this different strain and you may become ill again, although you may have some 'cross protection' due to encountering a similar virus previously.

Should I have a 'swine flu party' or try and catch swine flu now, so I will be immune to more serious strains that may emerge later?

No – it is irresponsible to purposefully catch the virus as you may perpetuate the spread. Also, as we don't yet know the profile of the virus, it is too soon to assume it is only a mild infection. And catching swine flu will not necessarily protect you from strains that may emerge later (see Is it possible to catch swine flu twice?).

Can my pet catch swine flu?

There is currently no evidence that pets are susceptible to this new strain of flu. The swine flu virus appears to be passing only from person to person or from human to swine. In general, flu viruses commonly infect just one species; for example, dogs and cats do not get seasonal flu from their owners.

What is the National Pandemic Flu Service and how does it work?

The National Pandemic Flu Service is a new self-care service that will give people with swine flu symptoms fast access to information and antivirals.

It is a dedicated website and a phoneline (0800 1 513 100 or textphone 0800 1 513 200) for people to get information, check their symptoms and get a unique number that will give them access to antivirals if necessary.

When you are given your unique access number, you will be told where your nearest antiviral collection point is. You should then ask a flu friend - a healthy friend or relative - to go and pick up the antiviral medication.

If you think you have swine flu, do not go out to your GP or A&E.

What documents are needed to be able to collect the antivirals?

The flu friend must show their own ID as well as that of the patient. The authorisation number and ID information will be checked to ensure it matches the information provided when the assessment of symptoms was completed.

The ID includes:

  • a utility bill,
  • passport,
  • a credit or debit card,
  • driving licence, or
  • NHS card.

Why has the government brought in this new service?

This new service will free up GPs, enabling them to deal with other illnesses that need their urgent attention.

Do I use the National Pandemic Flu Service if I'm in a high-risk group?

You should contact your doctor directly rather than using the National Pandemic Flu Service if:

  • you have a serious underlying illness,
  • you are pregnant,
  • you have a sick child under one year of age,
  • your condition suddenly gets much worse, or
  • your condition is still getting worse after seven days (five for a child).

How well trained are the Flu Service staff?

Experienced call operators have been trained for a minimum of three hours. Less experienced call operators have received one day's training. Agents are not medically trained and will not be able to answer any other questions, but they will be supported by healthcare professionals.

There will be NHS Direct trainers present in each call centre for the first two days. There will not be healthcare workers in attendance. Call centre managers will be able to contact the National Pandemic Flu Service clinical on-call desk with urgent issues.

Doctors from the Royal College of GPs will have a special liaison role with each of these call centres and will feed back problems or concerns that arise during the operation of the service.

Strict industry standard regulations are in place when employing staff. These include the right to work in the UK (therefore no illegal immigrants), satisfactory employment references and satisfactory character references.

A wide range of people are being recruited from all round the country and all are required to be able to speak English.

Will the algorithm distinguish between swine and other flu?

The algorithm is designed to identify cases of swine flu. However, the symptoms of seasonal flu are very similar and therefore there is likely to be some overlap with other circulating flu cases. As swine flu becomes more common, a higher proportion of influenza-like illness will be swine flu.

What can I do?

You can reduce, but not eliminate, the risk of catching or spreading swine flu by:

  • Always covering your nose and mouth with a tissue when coughing or sneezing.
  • Disposing of dirty tissues promptly and carefully.
  • Maintaining good basic hygiene, for example washing hands frequently with soap and warm water to reduce the spread of the virus from your hands to face, or to other people.
  • Cleaning hard surfaces, such as door handles, frequently using a normal cleaning product.

You should also prepare now by:

  • Confirming a network of ‘flu friends’ – friends and relatives – who could help you if you fall ill. They could collect medicines and other supplies for you so you do not have to leave home and possibly spread the virus.
  • Knowing your NHS number and those of other family members and keeping them in a safe place. It is not essential to have your NHS number in order to receive treatment, but it can help NHS staff to find your health records. You will be able to find your NHS Number on your medical card or other items such as prescribed medication, GP letter or hospital appointment card/letter.
  • Making sure you have a thermometer and adequate quantities of cold and cough remediesin your medicine cupboard in case you or your family are affected by swine flu.
  • Who should be wearing a facemask?

    The Health Protection Agency (HPA) recommends that healthcare workers should wear a facemask if they come into close contact with a person with symptoms (within one metre) to reduce their risk of catching the virus from patients.

    However, the HPA does not recommend that healthy people wear facemasks to go about their everyday business.

    Why shouldn't the general public wear facemasks?

    Because there’s no conclusive evidence that facemasks will protect healthy people in their day-to-day lives.

    The virus is spread by picking up the virus from touching infected surfaces, or by someone coughing or sneezing at very close range – so unless you are standing close to someone with the virus, wearing a facemask will not make a difference.

    There are concerns about the risks posed by not using facemasks correctly.

    Facemasks must be changed regularly as they are less effective when dampened by a person’s breath. People may infect themselves if they touch the outer surface of their mask, or may infect others by not disposing of old masks safely.

    Finally, wearing a facemask may encourage complacency. People need to focus on good hand hygiene, staying at home if they are feeling unwell, and covering their mouth when they cough or sneeze.

    So why have other countries gone down this route?

    This is an issue which each government has considered separately. France is encouraging the general public to buy their own masks for use as a precaution, but it is not stockpiling masks centrally from government funds and neither is the US.

    In other countries there is an existing culture of wearing facemasks for either the prevention of spreading illness or preventing the risks of pollution; this is not the case in the UK.

    What should I do if I think I’m infected?

    If you have flu-like symptoms and are concerned that you may have swine flu:

    • Stay at home, read up on swine flu symptomsand check your condition using the National Pandemic Flu Service.
    • Call your GP directly if:
      - you have a serious underlying illness,
      - you are pregnant,
      - you have a sick child under one year old,
      - your condition suddenly gets much worse,
      - your condition is still getting worse after
      seven days (five for a child).

    The National Pandemic Flu Service is a new online service that will assess your symptoms and, if required, provide an authorisation number which can be used to collect antiviral medication from a local collection point. For those who do not have internet access, the same service can be accessed by telephone on:

    • Telephone: 0800 1 513 100
    • Minicom: 0800 1 513 200

    For more information, go to the Flu Service - Q&A.

    If swine flu is confirmed, ask a healthy relative or friend to pick up your antiviral medication for you.

    In the meantime, take paracetamol-based cold remedies to reduce fever and other symptoms, drink plenty of fluids and get lots of rest.

    Do not go into your GP surgery, or to a hospital, as you may spread the disease to others.

    If I have been in close contact with an infected person, do I need treatment?

    You only need antiviral treatment if you have been diagnosed with swine flu or if a doctor decides that you are at serious risk of developing severe illness (see Will antivirals be given to people without flu symptoms?).

    Is swine flu treatable?

    Testing has shown that the swine flu can be treated with the antiviral medicines oseltamavir (brand name Tamiflu) and zanamivir (Relenza). However, the drugs must be administered at an early stage to be effective. See Treatment for more information.

    The UK already has a stockpile of antivirals sufficient to treat half the population. Also, orders of Tamiflu have been placed to increase UK supplies to 50m doses, enough to treat 80% of the population.

    What do antivirals do?

    Antivirals are not a cure, but they help you to recover by:

    • relieving some of the symptoms,
    • reducing the length of time you are ill by around one day, and
    • reducing the potential for serious complications, such as pneumonia.

    How large is the UK's stockpile of antivirals?

    The government has 23 million treatments of Tamiflu and 10.5 million treatments of Relenza. Orders of Tamiflu have been placed to increase UK supplies to 50m doses, enough to treat 80% of the population.

    Is one of the antivirals more appropriate for pregnant women and people with certain kidney conditions?

    Relenza is an inhaled drug that will be used for pregnant women and people with certain kidney conditions who are unable to take Tamiflu. See the section on Pregnancy and children.

    Will antivirals be given to people without flu symptoms?

    In most cases, no. Antivirals will generally only be given to people who have been diagnosed with swine flu.

    Doctors should not offer antiviral medication as prophylaxis (prevention) to contacts of cases unless, for example, a household member has serious underlying health problems or there are other special circumstances.

    Will my child experience nausea if they take Tamiflu?

    As is the case with many medicines, nausea is a known side effect of Tamiflu, in a small number of cases. Symptoms may lessen over the course of the treatment. It may help to take Tamiflu either with or immediately after food, and drinking some water may also lessen any feelings of nausea.

    How are those with confirmed swine flu getting access to antivirals?

    If antivirals are required, the National Pandemic Flu Service will provide you with an authorisation number which can be used to collect antiviral medication from a local collection point (see How is swine flu infection diagnosed?); or, if you are in a high-risk group, your GP will advise you over the phone on how to collect your antivirals.

    A healthy friend or relative can then pick up the antivirals for you from your local collection centre - usually a pharmacy or community centre.

    Should people be stockpiling their own antivirals?

    No. The government has a stockpile of antivirals sufficient to treat half the population, and is taking steps to increase this to cover 80% as an extra precaution. Therefore, antivirals should be available for everyone who gets ill in the pandemic and there is no need for people to buy their own.

    Does Tamiflu go out of date?

    The government has a programme to replace any expired doses under a 'rolling stock' system.

    If I take an antiviral and have side effects, whom should I inform?

    First, see your healthcare professional to check that you are ok. Then, report your suspected drug reaction to the Medicines and Healthcare products Regulatory Agency (MHRA) via their new online system (links to external site).

    This new webpage, based on the Yellow Card Scheme, helps the MHRA to monitor the safety of Tamiflu and Relenza.

    Anyone who does not have access to the internet can ask their healthcare provider to send a report on their behalf.

    When will there be a vaccine?

    Vaccines are complex and difficult to manufacture in large numbers. However, the Government has already signed contracts to get enough vaccine for the entire country as soon as it is available.

    While the first batches of vaccine will start to arrive in the autumn it will take several months to get enough vaccine for everyone. It will also take time to fully test the vaccine and to organise the vaccination of everyone in the country.

    To reduce the impact of swine flu, the NHS is focusing on those at the greatest risk first (see Who will be a priority for vaccination with the H1N1 swine flu vaccine?).

    Why does it take several months to produce a swine flu vaccine?

    The flu vaccine production process is long and complicated. Production technology is labour-intensive. The government's plans include two manufacturers, thus maximising chances of early development.

    If other countries are also being given advance supply guarantees, will we get ours first?

    The UK has a binding contractual agreement in place to ensure its supply.

    Does the current seasonal flu vaccine work?

    The current seasonal flu vaccine is designed to protect against H1N1, but it is unclear as yet whether this will offer any protection against the current strain of swine flu.

    How many stocks are available of seasonal vaccine?

    Flu vaccine is produced each year for the seasonal flu. Discussions are ongoing with manufacturers about how much may still be available. However, the government has determined that there are 430,000 doses of vaccine available in the UK.

    Who will be a priority for vaccination with the H1N1 swine flu vaccine?

    The Joint Committee on Vaccination and Immunisation has previously advised that the priority groups in relation to H5N1 (the bird flu vaccine) should be assumed to be:

    • frontline health and social care workers (to help ensure the NHS functions well),
    • older people and those in clinical risk groups (see Which people are most vulnerable from swine flu?), as flu can be more serious in these groups, and
    • under-16s, as protecting children can slow the spread of the virus in the population.

    The priority groups would be reviewed in light of evidence on the virulence and severity of the new virus in different groups.

    The government will still aim to achieve universal vaccination, but because the vaccine will have to be delivered over time, it is right that we start thinking now about groups to be prioritised.

    Will the vaccine still provide people with protection if the swine flu virus mutates between now and the autumn?

    At this stage, it is impossible to predict if or how the H1N1 swine flu virus will mutate (change). However, experiences with the H5N1 vaccine (bird flu vaccine) would suggest that an H1N1 vaccine (produced using the same processes) would also provide a high level of immunity against closely related strains. The level of cross-protection is expected to be greatest for more closely related strains.

    Does the NHS have enough syringes to administer the swine flu vaccine?

    Yes, orders have been placed to ensure there are enough syringes to administer the vaccine.

    What extra antibiotics have been purchased?

    Orders have been placed for 15.2m courses of antibiotics. They will play an important part in the response to the pandemic.

    Why do you need antibiotics in a pandemic?

    While antivirals may reduce the number of complications, there are still likely to be significant numbers of complications occurring in the pandemic. Some of the most common include bacterial infections in the respiratory tract and lungs, such as pneumonia. Antibiotics are needed to treat such complications.

    Antibiotics will be used to treat people in the community if they develop complications. In hospitals, antibiotics will be used to treat the sickest patients and may reduce the length of hospitalisation.

    How do I tell if my child has swine flu?

    Call your GP immediately if your child has any of the following symptoms and a temperature of 38°C or above or feels hot:

    • tiredness
    • headache,
    • runny nose and sneezing,
    • sore throat,
    • shortness of breath,
    • loss of appetite,
    • vomiting and diarrhoea, or
    • aching muscles, limb and joint pain.

    Of course, if you are worried about your child you should always call your GP for advice.

    One thing you can do right now is to make sure you have a digital thermometer to take your child’s temperature.

    If my child has swine flu, what should I do?

    If your GP confirms that your child has swine flu, they should stay at home and you should treat their symptoms like any other cold or flu. Make sure they drink plenty of liquids, get lots of rest and take over-the-counter cold and flu remedies to help control their temperature.

    Your GP will tell you whether your child should also take antiviral drugs. Antivirals, such as Tamiflu, shorten the symptoms by about a day and can reduce the risk of complications. Antivirals are only effective if taken within 48 hours of symptoms starting. If you are worried about your child, do not delay, call your GP immediately.

    However, antivirals can also have side effects. If your child’s swine flu symptoms are mild, you may not wish to give them antivirals. Your GP can advise you on this.

    Can children take antivirals?

    Yes, on the advice of a doctor. Tamiflu is safe for infants aged one and older, at a reduced dose. Relenza (an inhaler) can be used by children aged five and older under the supervision of an adult.

    What should I do if I become ill on holiday or on the flight home?

    Make sure you check in advance so you know where you can get medical advice if you or your family feel unwell on holiday. And make sure you have over-the-counter medication for flu, such as paracetamol or ibuprofen. Remember that children should not take aspirin.

    If you are travelling to Europe, make sure you have your free European Health Insurance Card (EHIC). This entitles you to any necessary medical treatment, including for swine flu, during a visit to another European Economic Area country. You can get an EHIC application form from the post office, by calling 0845 606 2030, or by applying online.

    If you do experience flu-like symptoms, keep away from public places to avoid spreading it. Then contact a health professional and tell them your symptoms.

    If you become ill on your flight home, alert the cabin crew to your symptoms. There are procedures in place for dealing with passengers who become unwell on flights, and the airline will advise port health officials on the ground that a passenger requires a health assessment and may need treatment.

    To access the Department of Health Swine Flu Information line when abroad, call 00 44 207 928 1010.

    Are the reports that 65,000 people are going to die true?

    It is wrong to suggest there will be a particular number of deaths per day. Scientific and clinical experts can use sophisticated modelling techniques to help us understand how the virus may behave, but that is all they can do - be a guide, not a prediction.