Sunday, July 26, 2009

Flu is everywhere in the media - on TV, radio and online. But is it everywhere in society? Not yet.

Sir Liam DonaldsonDespite all the headlines, it's worth remembering that the rate of flu in England and Wales is still below epidemic levels
Yesterday, the Chief Medical Officer for England, Sir Liam Donaldson, gave his weekly briefing to journalistson the spread of the virus.

I'm grateful to him and to the Royal College of General Practitioners for permission to use their slides.

First of all, the graph below shows where The red line - the current rate of flu - is heading up fast. This is highly unusual in the summer months. The rate of GP consultations last week stood at 155.3 per 100,000 of the population, double the previous week's. It is still below the epidemic threshold of 200 per 100,000. But that masks several hotspots in the UK.

Greater London has half a dozen areas where the rate of consultations is above 400 per 100,000. Not surprisingly, the areas that are more densely populated with higher proportions of children have higher levels of flu. This simply confirms that children are what are known as "super-spreaders" of flu, and you are more likely to get infected if you live in a city than if you are in the countryside.

In the next slide, if you compare the red line - current flu activity - with the last pandemic of 1968-70, you can see that we have a long way to go. As Sir Liam put it, this is a marathon, not a sprint. It's estimated that 100,000 people got flu in England last week. Put another way, this means that one in 500 got infected - or 499 out of 500 didn't. Infection rates are expected to soar later in the year, as you can see from the historical perspective.

Usually it takes six to 12 months to get an accurate estimate of the number of excess deaths caused by flu. But a rapid confidential investigation has been done by the chief medical officer into the deaths so far in England. As a result, the provisional number of deaths from swine flu in England since the outbreak began remains at 26.

That's a very small number if one wants to start working out percentages with any accuracy, but the next slide shows that 33% of deaths have been in the 0-15 age group and 39% in the 16-44 age group. The over-65 group - normally worst hit by seasonal flu - accounts for 17% of deaths.

Age distribution of fully investigated deaths

Again, I urge caution over the use of the percentages, given that we have had 26 deaths. But given that caveat, you can see that 67% of deaths have been among people with severe underlying health conditions (one example given to us was leukaemia).

Of those who died, 11% had moderate conditions (such as diabetes, controlled by insulin), 6% had mild conditions (such as high blood pressure, controlled by tablets) and 16% had been entirely healthy with no medical conditions.

A third of people in England who have died of swine flu have been healthy or had mild or moderate health conditions. The other two-thirds had severe conditions.

Underlying conditions information for fully investigated deaths

I have said this many many times, but it is worth repeating: the vast majority who become infected with H1N1 swine flu get a mild illness, and recover completely after a few days bed rest.

Among those who get complications, most recover completely after hospital treatment. While every death is a personal tragedy, fatalities represent a tiny minority of overall cases.

PS: I'm away for a while now - but remember that you can keep up with the latest swine flu news at

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