It seems swine flu confusion is spreading almost as fast as the pandemic. What should pregnant women do? Who will be vaccinated, and when?

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.

When can we expect a vaccine? Who will get the vaccine first?

Debora MacKenzie investigates at Newscientist.com | Read Full Story