Recently, from another thread:
Unless ... what if the incidence of polio - increased - due to improved hygiene ... unlike many other infectious diseases ...
I recently came across the idea and would like to learn more about it.
This idea is mentioned here:
Salk Vaccine Trial
From the same source above:
Strangely enough, severe polio tends to be rare in communities with poor hygiene. The reason is that the virus is abundant in such communities, so babies are likely to be exposed to the virus early, while still protected with antibodies from their mothers. Later (assuming that they survive other diseases associated with poor hygiene), these children develop their own antibodies to the virus. The net effect is that in communities with poor hygiene, most people have a natural immunity.
Can anyone pls share some sources etc that might support/refute this claim?