California measles outbreak reportedly involves Orthodox Jewish community

An ongoing measles outbreak in California is reportedly affecting a local Orthodox Jewish community.

Jeffrey Gunzenhauser, MD, MPH, interim health officer for the Los Angeles County Department of Public Health, said 20 cases of measles have been confirmed so far, including 18 in the county encompassing Los Angeles. Gunzenhauser would not provide information on any individuals or groups that were being affected by the outbreak because it was private information and there was no compelling public health reason to inform the public, he said.

“We can say that the outbreak has largely been limited to unvaccinated people in a single social group and the disease is spreading among personal contacts in the group,” Gunzenhauser told Infectious Disease News.

According to the Los Angeles Times, a rabbi who runs a Jewish health care foundation in the city said county health officials told him the outbreak was affecting the Orthodox Jewish population.

The outbreak began in early December, about 5 months after a new state law eliminating all nonmedical vaccine exemptions, including those based on personal beliefs, took effect in California. The health department could not confirm vaccination against measles in any of the 18 patients in Los Angeles County and has “reached out to leaders of the affected social group to encourage vaccination,” Gunzenhauser said.

“It is still ongoing,” he said. “Most of the cases occurred in the last 3 weeks of December. There have been fewer cases since then, but it is possible additional cases may occur.”

Under the new vaccine law, SB-277, which took effect on July 1, all schools in California are required to check the immunization status of incoming kindergarteners, seventh-graders and all new students for 10 childhood diseases, including measles. The bill was introduced in February 2015 amid a nationwide measles outbreak linked to two Disney theme parks in Orange County, California.

According to Gunzenhauser, the age range of patients in the current outbreak is “wide,” but most cases involve adolescents or young adults. He said the health department identified more than 2,000 contacts who were in close proximity to one or more patients while they were infectious. “Slightly less than 10%” of those contacts were unvaccinated, Gunzenhauser said. He said more than 50 of them received early prophylaxis that may have prevented measles, and the rest were offered vaccination.

According to the CDC, two doses of the measles, mumps and rubella vaccine are about 97% effective at preventing measles. There has been a dramatic decline in measles in the United States from an estimated 3 to 4 million cases a year prior to the launch of a vaccination program in 1963 to just 70 documented cases in 2016, according to the CDC.

The Americas were declared free of measles in September, after going 14 years without an endemic case — the first WHO region to rid itself of the disease that once killed hundreds of people in the U.S. each year. But travel-related outbreaks do still occur.

In 2013, a measles outbreak that sickened dozens of people in two Orthodox Jewish communities in New York City was linked to a teenage boy who had been studying in London and returned to Brooklyn while still infected. The teen was part of a large family who had refused vaccination, which allowed the disease to spread.

Gunzenhauser said the health department would not comment on where infections have occurred during the California outbreak — school, work, etc. — but would disclose the location of any potential public exposures to measles if they occur.

“There have been no infections spreading in the general community,” he said. – by Gerard Gallagher

Disclosures: Gunzenhauser works for the Los Angeles County Department of Public Health.