WASHINGTON — Unvaccinated adults had a “significant” impact on the early days of the New York State measles outbreak, with 51% of cases during the first month being attributable to them, according to data presented at IDWeek.
Two measles outbreaks in New York that sickened almost 1,000 people — one in New York City, the other in Rockland County — have both been declared over. Debra Blog, MD, MPH, director of the division of epidemiology at the New York State Department of Health, and colleagues analyzed data on measles cases occurring outside of New York City from October 2018 to September 2019.
“We wanted to look at the role that adults played in the outbreak,” Blog told Infectious Disease News. “There was significant transmission to others for these cases. Most adults — 82% — who became ill with measles were unvaccinated or had unknown vaccination status.”
Blog summarized the study findings, noting that although 80% of cases occurred in children, adults did play a significant role in transmission, especially early in the outbreak.
Their study included 371 cases, 79 (21%) in adults — four born before 1957, of whom three were unvaccinated and one had unknown vaccination status. Of the cases in adults born during or after 1957, 65 (87%) were unvaccinated or had unknown status, three had received one dose of vaccine and seven had received two doses.
The researchers reported that five of 11 internationally imported cases were in unvaccinated adults or adults with unknown status. They found that 26 of the 51 cases recorded during the first month (51%) were attributable to adults, with 42% of those cases occurring in children.
“The majority of measles cases occurred in unvaccinated children, emphasizing the importance of ongoing and focused efforts on pediatric vaccination,” Blog concluded. “However, measles cases in unvaccinated adults played an important role in both importations and disease transmission early in the outbreak.” – by Caitlyn Stulpin
DuFort E, et al. Abstract LB16. Presented at: IDWeek; Oct. 2-6, 2019; Washington.
Disclosure: Blog reports no relevant financial disclosures.