[leu25iso]

That's the reason you need a tetanus shot every ten years, but never need to redo your polio immunity IF you got the attenuated Sabine vaccine.

But aren't both examples above related to the frequency of change in the immunizing antigens (not all are well preserved in killed vaccines). Even when killed is not as good as attenuated, isn't protection for more than several months?

[riri]

Researchers Tout Flu Shot as Quicker, More Accurate