I was reading this report on Measles from 1967,
and it explains the pattern of measles outbreaks happen according to the number of the population immune vs. susceptible. The numbers given here reach the conclusion that when 55% of the population is immune, epidemics will not occur.
I suppose this is why they believed that with the introduction of measles vaccine, they could wipe out the disease in a single year... Really it doesn't seen too difficult to vaccinate enough kids to put the level above 55%, especially as children being born is what increases the number of susceptibles.
The chart at this link says for measles, the current estimate for herd immunity to function is 83-94%.
What is going on here? With these number discrepancies? Is this just because the wild infection would give immunity for life and the vax just a varying amount of years, and the 83-94% number is adjusted for vaxed ppl who lost immunity? Or is it that the '67 info had problems? Some other issue concerning “real” vs vax immunity?
I wonder how much of the population is actually immune to measles... Especially adults too young to get wild cases and who have gone long without boosters. Anyone have any numbers/links for that? I don't even know if that is possible to know.
Merck MMR II package insert says
I guess they just don't know much more than that... they *think* it will last a lifetime, but I've heard some anecdotes to the contrary.
National Immunization Survey doesn't even survey what % adults had MMR vax (or wild infection)
Of interest on wikipedia (Couldn't get to the full text through footnote)
I am not sure as to why the difference between the 60's and more current data but I have a question/comment as to the long term effectiveness of the vaccine. They state that there are antibodies years after vaccination but what are the rates of naturally acquired "boosters" from the environment? I think it is impossible to determine how long a vaccine lasts without putting the vaccinated individual in a bubble with no outside contact and testing annually.
AP, Homeschooling, Part-Time working mom with 3 rambunctious boys all born with love at home. (04 & 08 & 12).
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