Measles at Fort Bliss and El Paso, 2019: Six Cases, No Known Source

On July 3, 2019, Army Public Health at Fort Bliss, Texas, got a report of suspected measles in a woman who worked on the post, lived off it, and had not traveled. Fort Bliss, one of the largest U.S. Army posts, is in El Paso County — more than 800,000 residents, bordering Mexico and Juarez (population 1.4 million). El Paso County's last confirmed measles case had been in 1993, and its last outbreak in 1990.

The same day, the City of El Paso Department of Public Health alerted the Texas Department of State Health Services to a second suspected case: an unvaccinated 3-year-old living on Fort Bliss, with no travel, whose father was an active-duty soldier. Both were confirmed on July 9.

The response

City health department

• advisories to local doctors and contact tracing
• longer hours at immunization clinics for MMR vaccine, and immune globulin from the state for exposed infants, pregnant women and people with weak immune systems
• a telephone help line, an education task force across the county, letters to every school superintendent, and contact with Mexican health officials across the border

Fort Bliss

• child care and youth programs limited to children up to date on MMR
• active monitoring of all post medical facilities, and daily meetings with senior leaders

State and federal

• daily calls coordinating the city, the Army and the state
• a statewide syndromic surveillance system watching for measles-like illness
• a CDC team, invited at the end of July

The cases

Four more cases brought the total to six, with rashes starting between June 30 and July 19.

• Three were children aged 1–4, completely unvaccinated — no MMR or any other vaccine.
• Three were adults: one had lab evidence of immunity suggesting past vaccination; the other two had unknown status.
• Three were linked to Fort Bliss — one child and two adults, none on active duty.
• All six carried an identical D8 strain.
• 91 specimens from people with measles-like symptoms were tested between July 3 and September 3; some were also tested for rubella, with none found.

About two weeks before their rashes, the first two patients had visited the same large shopping center, where someone with undiagnosed measles may have been. But the original source was never found, and no links were found among the other four. The outbreak was declared over on September 3, 2019, after two incubation periods (42 days) with no new case.

The lesson

The joint response likely prevented a larger outbreak, but measles remains a risk to anyone unvaccinated. Anyone without presumptive evidence of immunity to measles, mumps and rubella should get MMR vaccine as the Advisory Committee on Immunization Practices recommends. Evidence means: documented measles vaccination (one dose on or after the first birthday for preschoolers and adults not at high risk; two doses for school-age children and high-risk adults), lab evidence of immunity or disease, or birth before 1957.

Sources

Based on "Notes from the Field: Measles Outbreak on an Army Post and a Neighboring Community — El Paso, Texas, July–September 2019," by Joshua Vance and others, MMWR Morbidity and Mortality Weekly Report, volume 69, Centers for Disease Control and Prevention; a work of the United States government in the public domain.