ttxela2 said:
I can't think of anything else that requires such frequent vaccination, 3 in the space of a year so far, can anyone explain in simple terms why the effectiveness wanes so quickly? I guess in terms of poorer countries this will also be an issue, I've heard statistics of 40% effectiveness lost in a few months?
Rabies vaccine is 3 doses, normally given over a minimum of 28 days.
Google suggests Tetanus vaccine is given (to unvaccinated adults) as three doses, two close together and one 6-12 months later. WHO guidelines are 6 doses total: three doses in early childhood, one booster aged 12-13 months, one aged 4-7 years and then one aged 9-15 years, plus adult boosters every 10 years.
I imagine there are others where you get many injections (e.g. pertussis?).
I think part of the reason is that we are aiming for very high levels of immunity.