Vaccination Rates Decline: How Many Children at Risk?

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(CBS/AP) Though the vast majority of children are getting their routine vaccinations, health officials say they're concerned about a recent drop in measles vaccinations.

The Centers for Disease Control and Prevention released results Thursday of a study it conducted on vaccination rates for children ages 19 through 35 months.

The study, based in part on a 2009 telephone survey of parents of more than 17,000 children, found that more than 90 percent of the children received most routine vaccines, and more than 99 percent got at least one.

But the immunization rate for the measles-mumps-rubella vaccine dropped from 92 percent in 2008 to 90 percent, according to the study. That's a worry, given the recent rise in cases of measles.

The rate of children being vaccinated against whooping cough also declined slightly, but health officials believe that getting boosters to teens, adults, and people who are around infants is a more important way to attack the recent whooping cough outbreak in California.