By Carolyn Crist

(Reuters Health) – – Monitoring for measles in U.S. workplaces needs improvement, especially in the healthcare sector, an occupational safety expert argues.

Measles cases have reached a 27-year high in the U.S. To help prevent transmission, officials need to more closely monitor how and where the cases spread, Christopher Brown, a health scientist in the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA), writes in a letter published in the American Journal of Infection Control.

“Good disease surveillance . . . is critical to allow for effective interventions that reduce or stop disease spread and keep people healthy,” Brown told Reuters Health by email, noting that he wrote the research letter out of his own personal interest, not in his official capacity with OSHA.

During past measles outbreaks, Brown writes, work-acquired infections were common and could have been prevented, especially among healthcare workers.

For example, about 2% of the 1,300 non-imported U.S. cases recorded between 2001 and 2014 were linked to occupational exposures among healthcare workers. Between 1998 and 2010, healthcare workers made up about 23% of cases associated with 31 different outbreaks worldwide. This includes three U.S. outbreaks.

The CDC’s National Notifiable Diseases Surveillance System monitors the spread of outbreaks, but the numbers don’t typically include details related to occupational exposures, Brown said.

Local and state health departments should try to report this information, and the CDC should, in turn, make the information available publicly so researchers can track exposures and infection patterns, he said. This type of surveillance is done for high-consequence diseases such as Ebola but not for outbreaks that aren’t considered “novel or clinically severe,” Brown said.

“For individuals who work in a setting where they might have an increased risk of being exposed to measles, it is important for them to make sure they have the recommended number of doses of measles, mumps, rubella (MMR) vaccine,” said Amy Parker Fiebelkorn of the CDC Vaccine Task Force, who wasn’t involved in the letter.

“For adults who are healthcare personnel, international travelers, and students in post-secondary educational institutions, the recommendation is for two MMR doses,” she told Reuters Health by email. “For all other adults, one dose of MMR is sufficient. MMR vaccination is the best prevention against measles.”

Since the beginning of this year, the U.S. Centers for Disease Control and Prevention (CDC) has logged more than 1,100 measles cases, which represents a 300% increase over 2018, Brown writes in the letter.

Some of the cases have led to outbreaks in New York State, California, Pennsylvania and Washington.

“Large outbreaks of measles are occurring globally right now, and in this mobile world, it can be brought into the U.S., which becomes contagious among the pockets of unvaccinated people,” said Dr. Jennifer Rosen of the New York City Department of Health and Mental Hygiene, who wasn’t involved in the letter.

“The first case in the New York City outbreak was an unvaccinated child who acquired measles while traveling abroad, which led to several other cases,” she told Reuters Health by phone. “Vaccination is the best way to protect yourself from getting measles.”

SOURCE: American Journal of Infection Control, online July 23, 2019.