Vaccines against swine flu, aka H1N1, ready next month

Four vaccines against the new infuenza, the one we used to call swine flu but now is known as H1N1, will be ready for distribution next month in the US.

This according to the government, which also issues another piece of good news: it appears that a single vaccination will keep this more-serious-than-usual flu at bay. For a while it was thought that immunity to H1N1 would require at least two shots, but the experts now say not. These findings apply to adults, though. It's still not clear whether children may need more than one dose.

Health authorities have worried that the coming Northern Hemisphere flu season will be worse than usual. A pattern with new flu viruses like this one is that they tend to be particularly severe the winter after they first surface. Hence the hurry to make a vaccine available quickly.

And of course we'll still have with us the regular old seasonal flu, which kills several thousand in the US every year. There's a vaccine against that one too, as usual.

Dealing with the flu this year will be particularly tricky because H1N1 and seasonal flu tend to attack different populations. The young are particularly vulnerable to H1N1, while seasonal flu mostly preys on the elderly and infirm.