Also according to WHO, the inclusion of the meningococcal vaccine in infant vaccinationprograms in the Netherlands and Canada has shown efficacy of 87% to 98% in various studies.
Because vaccinationprograms have been so successful, very few people know someone who had polio, and a lot of parents of young children never even had chickenpox, he says.
Screening is now routine for infants, and expanded vaccinationprograms have helped reduce new infections, but many immigrants and AAPIs born in the US before the 1990s have never been tested.