CHICAGO (AP) --
Infants
whose
mothers were vaccinated against
measles
inherit few natural antibodies and are far more likely to catch
the virus than infants of older, unvaccinated mothers, according
to a study released Monday.
The study confirms what public health officials anticipated when
the vaccine was licensed in 1963, that the population would lose
natural immunity to measles.
Researchers from the federal Centers for Disease Control and
Prevention found that unvaccinated infants of mothers born after
1963 were 7.5 times as likely to catch measles as unvaccinated
infants of mothers born before 1963.
Findings appear in the November issue of Pediatrics, and
researchers said they underscore the importance of getting babies
vaccinated by 12 months of age.
Measles kills a million people worldwide each year, and public
health officials want even better than the 90 percent U.S.
immunization rate.
Measles once was a rite of passage in U.S. childhood -- at its
peak in 1941, it infected 894,134 Americans and killed 2,279. Last
year, only 100 cases were reported.
Having had measles leaves much higher levels of disease-fighting
antibodies in the blood than being vaccinated. Before the vaccine,
infants acquired significant antibodies from their mothers at
birth, which protected them until the antibodies were depleted.
In the new study, the researchers interviewed mothers of 128
infants in New Jersey and Texas who were exposed to measles during
its resurgence in the United States between 1989 and 1991, when it
infected 55,000 people and killed 120.
