Clusters of Unvaccinated Kids Could Lead to More Disease Outbreaks

Despite the near-eradication of measles in the U.S. 15 years ago, health officials are concerned that the disease could make a comeback after large outbreaks have occurred in California and other states over the past two years, the Wall Street Journal reports.

Background

According to CDC, measles has not been indigenous to the U.S. since 2000 (McKay/Whalen, Wall Street Journal, 1/25).

However, CDC reported that there were 644 new measles cases in 27 states last year, the largest annual number in nearly 25 years, according to the Washington Post's "Wonkblog." Most individuals who contracted the disease were unvaccinated, including dozens affected by a recent outbreak in California (Ingraham, "Wonkblog," Washington Post, 1/22).

The California Department of Public Health has confirmed at least 83 cases of measles in seven states and Mexico related to an outbreak that began at Disneyland (California Healthline, 1/27).

Details of Concerns

Gregory Wallace -- head of CDC's domestic measles, mumps, rubella and polio team -- said vaccination rates among kindergarteners for measles, mumps and rubella have remained high since the mid-1990s, at about 94.7% in the 2013-2014 school year.

However, experts are concerned that outbreaks are becoming more common, in part because of clusters of unvaccinated children living in the same areas (Wall Street Journal, 1/25).

A recent study of 154,424 children born between 2000 and 2011 found five areas with clusters of unvaccinated children in California, including an area south of Sacramento, where 13.5% of children were unvaccinated or under-immunized. In comparison, the average rate of vaccine refusal outside of those clusters was 2.6% (California Healthline, 1/20).

According to data compiled by Bloomberg, California ranks 39th overall for its vaccination rates, with 65.3% of children receiving the seven CDC-recommended vaccines (Ingraham, "Wonkblog," Washington Post, 1/27).