Immigration and Customs Enforcement has provided more than 25,000 doses of the measles-mumps-rubella vaccine, or MMR vaccine. Of the three viruses, however, the vaccine is least effective at protecting against mumps. Two doses of mumps vaccine are 88% effective at preventing the illness, while one dose is 78% effective. After about a decade, its efficacy wanes further.

In comparison, the MMR vaccine is more than 90% effective at preventing the other illnesses.

Approximately 16,000 cases have been reported nationwide in the total population since 2015. Cases tend to occur in crowded communities where people have had prolonged contact with each other, including on college campuses.

Despite efficacy concerns, some protection is better than none. Before the vaccine was widely used in 1967, there were 186,000 cases reported in the United States each year, according to the CDC.

The mumps outbreaks among migrants, many of whom entered illegally, spiked between March and June, which is when the highest number of people were arriving at the border and being transferred from Customs and Border Protection to ICE centers where they are held up to three weeks. The cases were spread across 19 states, with 898 migrants and 33 staff members infected.

The mumps breakout started last October when the Texas Department of State Health Services confirmed five cases among detainees transferred into its care. The CDC concluded 84% of cases were a result of exposure while in ICE custody or in another federal agency’s care. Only 5% picked up the infectious disease prior to entering the U.S. from Mexico, and the point of exposure for the remaining 11% was undetermined. Roughly 19 in 20 cases were found in men.

The report is the first of its kind and captures the biggest-ever mumps outbreak in U.S. immigration facilities. Of the 57 facilities where mumps were reported, 34 were operated by private companies, 19 were county jails, and four were ICE facilities.

Good morning and welcome to the Washington Examiner’s “Daily on Healthcare!” This newsletter is written by senior healthcare reporter Kimberly Leonard (@LeonardKL) and healthcare reporter Cassidy Morrison (@CassMorrison94). You can reach us with tips, calendar items, or suggestions at dailyonhealthcare@washingtonexaminer.com. If someone forwarded you this email and you’d like to receive it regularly, you can subscribe here.

NOTE TO READERS: “Daily on Healthcare” will not publish Monday, Sept. 2, in observance of the federal Labor Day holiday. We’ll be back Tuesday, Sept. 3.

SURGEON GENERAL WARNS TEENS: ‘THIS AIN’T YOUR MOTHER’S MARIJUANA’: Surgeon General Jerome Adams warned teens and pregnant women Thursday that marijuana on the street these days is more potent than ever before and is unsafe in any quantity. Adams said he was “sounding a national alarm about the harmful effects of marijuana use on the developing brain,” including on adolescents and young adults, and on babies in utero who are born underweight because of women using the drug while pregnant.

PENCE VOWS TO MAKE VETERANS AFFAIRS HOSPITALS RELIGIOUS AGAIN: Vice President Mike Pence attacked the merits of a lawsuit to remove a Bible from the Manchester, New Hampshire, VA hospital, saying to the American Legion National Convention the lawsuit is a relic of the Obama administration: “Under the last administration, VA hospitals were removing Bibles and even banning Christmas carols in an effort to be politically correct. But let me be clear: Under this administration, VA hospitals will not be religion-free zones.” The suit, filed in May by the Military Religious Freedom Foundation, challenges the display of the Bible carried by a World War II vet because it violates the First Amendment by seeming to favor one religion over others.

AZAR PROMISES ‘AGGRESSIVE RESPONSE’ TO EBOLA OUTBREAK THAT HAS KILLED 2,000: After the World Health Organization announced the death toll of the current Ebola outbreak in the Democratic Republic of the Congo — 2,006 — Health and Human Services Secretary Alex Azar said the U.S. is taking an aggressive approach to ending the second largest recorded outbreak. “The United States … has already led in providing access to the best available vaccines, therapeutics, diagnostics, and epidemiological expertise needed to stop the spread of Ebola and save lives,” Azar said Thursday. He said ending the epidemic would remain “a top global health priority” for the Trump Administration.

MYTHBUSTERS: THE ‘GAY GENE’ ISN’T REAL: A single “gay gene” that supposedly determines a person’s sexual preference is not real, according to geneticists from Denmark, Sweden, the United Kingdom, and the U.S. With the help of commercial DNA kits including 23andMe, the researchers studied the genes of 470,000 people to prove there is: “an important role for the environment in shaping human sexual behavior and perhaps most importantly [that] there is no single gay gene but rather the contribution of many small genetic effects scattered across the genome.”

The Rundown

The Associated Press Probes of e-cigarette giant Juul under way in Illinois, DC

Ventura County Star Two suspected vaping injury cases reported in Ventura County; THC involved

The Atlantic Most 2020 Democrats want a public option. L.A. already has one.

The Advocate Family questions how woman died from ketamine use at Baton Rouge psychiatric hospital

Kaiser Health News California requires suicide prevention phone number on student IDs

Calendar

FRIDAY | Aug. 30

Congress in August recess.

MONDAY | Sept. 2

Labor Day.

WEDNESDAY | Sept. 4

4 p.m. Boston. Washington Post Live event on “Chasing Cancer.” Details.