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The main reason infants fail to respond to measles vaccine is the presence of antibody to
measles, which infants get from their mothers during pregnancy. It takes only a very
small amount of antibody to kill the measles vaccine. About 5% of infants still have
enough measles antibody at 12 months of age to do just that.
Studies of children who failed to respond to the first dose of vaccine at 12 to 15 months
of age have shown that over 99% of them did respond normally to the second dose.
Studies of outbreaks in schools have confirmed that measles is very rare in children who
have had two doses of measles vaccine.
This document was published by the Canadian Paediatric society, 1997.
Posted by the
Canadian Paediatric Society, July 1997.