Babies of vaccinated moms more prone to measles, study shows

Source: Nando Times – Infants whose mothers were vaccinated against measles inherit fewer natural antibodies and are far more likely to catch the virus than infants of older, unvaccinated mothers, a study released Monday reveals.

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.