The United States may soon lose the measles elimination status it achieved in 2000, the CDC recently warned.
The warning came just before the number of cases in the country since January topped 1,000. Outbreaks have popped up recently across the country, including two large outbreaks in New York City and Rockland County, New York. Both outbreaks have stretched on for nearly 8 months and now threaten to make measles an endemic disease once again.
The CDC attributes the U.S.’s elimination status to the “availability and widespread use of a safe and highly effective measles vaccine,” according to a press release. Measles is largely preventable through two doses of vaccine. In 2017, the overall national coverage for the MMR vaccine among children aged 19 to 35 months was 92.7%, according to the CDC. Coverage levels vary by state, but 11 states in 2017 had MMR coverage levels of less than 90%. Vaccination rates of 96% to 99% are needed to preserve herd immunity and prevent future outbreaks, according to researchers. Globally, coverage with the first dose of measles vaccine has stalled at 85%, and coverage with the second dose stands at 67%, according to WHO.
“Elimination status is lost when a single strain of measles circulates for 12 months or longer, whereupon a country is considered to have re-established endemic measles,” Tarik Jašarević, a WHO spokesman, told Infectious Disease News.
According to the Pan American Health Organization (PAHO), two countries have lost their elimination status in the Americas — Venezuela in 2018 and Brazil in 2019. The other 33 PAHO member states have retained their elimination status, which may soon change if the measles outbreaks in New York continue through summer and fall, according to the CDC.
There are no specific ramifications when a country loses its certification, according to PAHO. The organization has made recommendations to countries in the region to maintain measles elimination, including to redouble efforts to vaccinate their populations at 95% coverage and above, strengthen surveillance to detect possible cases and implement measures to quickly respond to any suspected cases. – by Joe Gramigna
CDC. U.S. measles cases in first five months of 2019 surpass total cases per year for past 25 years. https://www.cdc.gov/media/releases/2019/p0530-us-measles-2019.html. Accessed June 6, 2019.
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Majumder MS, et al. JAMA Pediatr. 2015;doi:10.1001/jamapediatrics.2015.0384.
PAHO. 29th Pan American Sanitary Conference. https://www.paho.org/hq/index.php?option=com_docman&view=download&category_slug=29-en-9249&alias=41468-csp29-inf-5-e-468&Itemid=270&lang=en. Accessed June 6, 2019.
WHO. New measles surveillance data for 2019. https://www.who.int/immunization/newsroom/measles-data-2019/en/. Accessed June 6, 2019.
WHO. Weekly epidemiological record. https://apps.who.int/iris/bitstream/handle/10665/275392/WER9341.pdf?ua=1. Accessed June 6, 2019.
Disclosures: Jašarević is employed by WHO, and Oliel is employed by PAHO.