When can we expect a vaccine?

When can we expect a vaccine?

It's not clear. The World Health Organization estimates that, by August, global production of the vaccine will reach 94.5 million doses per week. But this estimate relies on all companies using formulations with novel adjuvants – additives to the vaccine that boost the immune response and reduce the amount of virus needed for each dose.

However, the adjuvants have not been approved for use in the US. Last week the US National Biodefense Science Board said that in order to have any vaccine available by September, the US should stick to the well-tested formulation of the seasonal flu vaccine – with 15 micrograms of the main viral protein, haemagglutinin, per dose.

The WHO warns though that if adjuvants are not "fully used" the amount of vaccine available per week will fall by 40-50 per cent.

Who will get the vaccine first?

Again, 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.