Controlling the Measles Outbreak in the Southwest
Vaccination continues to be the safest, most effective way to prevent the spread of measles.
Seminole, Texas – February 27: Signs point the way to measles testing in the parking lot of the Memorial Hospital Emergency Department in the Seminole Hospital District.
An outbreak of measles in West Texas and New Mexico has grown to over 250 cases and resulted in two deaths, including an unvaccinated child.
Measles was considered eliminated in the U.S. in 2000, thanks to the highly effective MMR vaccine and high vaccination rates. But because measles is so contagious, at least 95% of a community must be vaccinated to prevent outbreaks, says Bill Moss, MD, MPH, a professor in Epidemiology and executive director of the International Vaccine Access Center.
In the March 7 episode of Public Health On Call, Moss spoke with Lindsay Smith Rogers about how the outbreak is growing, the challenges to controlling it, and how the average person can know whether they’re at risk of contracting measles. He also clarifies the role vitamin A can play in treating—but not preventing—measles and why it is not a replacement for vaccination.
What is the latest on the outbreak in the Southwest U.S.?
The state of Texas has been really good about updating its Health Services website with information about the outbreak. As of March 4, they had reported 159 cases in 2025. Most of those cases—107 of them—are from Gaines County. And the number of cases has been increasing. [Editor’s note: The Texas Department of State Health Services updates its outbreak alert page every Tuesday and Friday. Since this conversation was recorded, the latest totals as of March 11 are: 223 cases (156 in Gaines County), 29 hospitalizations, and one death.]
Unfortunately, 22 of those cases have been hospitalized. And there was one death, of an unvaccinated school-age child, which is tragic because it was a very easily preventable death. The child had no underlying conditions; it’s important for people to know that this was an otherwise healthy child.
In addition to the ongoing transmission from this outbreak, there have been some imported cases into Texas—four reported cases have been associated with international travel.
Most of the cases in Texas are in school-age children between ages 5 and 17 who are either unvaccinated or have unknown vaccination status, and a few are among children who received a single dose of the MMR vaccine.
What is known about this outbreak and the community where it’s occurring?
This outbreak started in a Mennonite community in West Texas where there are low vaccination rates. Many of the children are homeschooled or attend smaller private schools, and many are unvaccinated.
This is not atypical for the larger outbreaks that we’ve seen in the United States in the recent past. In 2019, the U.S. saw 1,274 measles cases, including a large outbreak of slightly more than 900 cases in an Orthodox Jewish community in New York. In 2014, there was a measles outbreak of 383 cases in an Amish community in Ohio.
These larger measles outbreaks tend to occur in close-knit communities with very low vaccination rates.
Are the outbreak in New Mexico and cases reported in other states related to the outbreak in Texas?
Yes, we are seeing measles cases being exported from West Texas to other counties within Texas, but also to other states. The state with the next-highest number of cases is New Mexico, on the border with Texas—as of March 7, the New Mexico Department of Health has reported 30 cases and one death.
There have also been cases of measles reported elsewhere in the U.S., as far from Texas as New Jersey and Kentucky. But we aren’t seeing outbreaks in other states of the size that we’re seeing in West Texas, in that community with low measles vaccination coverage.
How do we stop this outbreak?
The way we stop and prevent measles outbreaks is through measles vaccination. We have a very highly effective measles vaccine—about 93%–95% of people are protected after just a single dose. That percentage is even higher—97% or more—if they get their second dose as recommended.
Individuals who have had two doses of the measles vaccine don’t need to worry.
What are the challenges to stopping the outbreak?
In many countries, it’s an issue of access. For example, where I’ve worked in sub-Saharan Africa, it can be challenging to get the measles vaccine to children who live in remote rural areas or areas of conflict.
In the U.S., however, measles vaccines are readily available; the problem is on the demand side. It’s a complex issue that requires addressing people’s concerns about the measles vaccine and having the right messengers to get the information to communities. It requires talking to people and trying to address misunderstandings—and probably misinformation and disinformation—that they’re hearing.
In the current outbreak, it may be religious leaders who need to be the trusted messengers to provide information and address the concerns of the community.
Is vitamin A effective in preventing or treating measles?
There's a long history of studies—including by former Bloomberg School dean Al Sommer—showing that vitamin A supplementation in communities with a high prevalence of undernutrition and vitamin A deficiency can prevent measles mortality, and that giving vitamin A to children hospitalized with measles can reduce measles mortality.
That said, there are some important caveats to the use of vitamin A for measles:
- Vitamin A does not prevent measles virus infection like the vaccine does. Unvaccinated people given vitamin A could still get measles.
- Vitamin A doesn’t eliminate the risk of measles mortality—it maybe cuts the risk in half.
- The real impact of vitamin A is in populations with a high prevalence of undernutrition and vitamin A deficiency, which is generally not the case in the U.S.
While it can be given to children here in the U.S. under the supervision of a health care provider—particularly children who are immunocompromised or have been hospitalized with measles—vitamin A is not a cure or prevention for measles. There is also toxicity associated with vitamin A if an individual takes too much of it.
The bottom line: Vitamin A is an effective tool to try to reduce measles mortality, particularly in high-burden settings outside of the U.S., but it's not a tool to prevent measles the way the measles vaccine is.
The real impact of vitamin A is in populations with a high prevalence of undernutrition and vitamin A deficiency, which is generally not the case in the U.S.
Are steroids or antibiotics useful in treating measles?
Steroids are not a standard therapy for measles. Measles can impair the immune system and lead to secondary bacterial infections like pneumonia—in fact, steroids might only exacerbate such an infection.
There is a role for antibiotics in children who develop a secondary bacterial infection, such as an ear infection or pneumonia. But it is not recommended that all children with measles be treated with antibiotics.
How concerned should people be if they’re not living in a community where an outbreak is occuring?
Individuals who have had two doses of the measles vaccine don’t need to worry—they can be very confident they are protected. If you've had one dose, there's a slightly higher risk that you might get measles if you're exposed to the virus, but you would likely experience milder illness.
The CDC recommends that people who are traveling internationally make sure they have received both recommended doses of measles vaccine.
If someone is traveling to a place in the U.S. where a measles outbreak is occurring, they need to weigh their risk of coming into contact with an individual with measles.
Some people may be more susceptible to severe measles, including those whose immune systems are weakened due to chemotherapy or underlying diseases, and infants younger than 12 months old.
Should people get their measles antibody levels tested?
Generally, I don’t recommend people get their antibody levels tested because the results can be misleading. Many of the tests are not sensitive enough to detect low antibody levels, so individuals may be misclassified as being susceptible to measles.
If there is any doubt about a person’s measles vaccination history, it’s very safe to get another dose of measles vaccine. You don't need to follow that up with measuring antibody levels.
Would a mask help prevent transmission of measles?
Measles virus is transmitted through droplets and through aerosols. If worn properly, a tight-fitting N95 mask should reduce the risk of coming into contact with measles virus.
What might happen next with this outbreak? Is it showing any signs of slowing down?
I don’t recommend people get their antibody levels tested ... If there is any doubt about a person’s measles vaccination history, it’s very safe to get another dose of measles vaccine.
It’s tricky to predict what will happen, but we’re not seeing signs of this outbreak slowing down. What happens next is a matter of whether the virus gets into other communities where there is low vaccine coverage.
For the sake of comparison, here in Maryland, we had one measles case in 2023 and one case in 2024. Someone was in the state with measles, but because we have very high measles vaccine coverage here, that didn’t result in a larger outbreak.
It’s not unexpected to see just one or two cases in communities with high vaccine coverage.
But if someone with measles goes to another community with a large proportion of unvaccinated individuals, we can expect to see another large outbreak, which can then seed other sites.
This interview was edited for length and clarity by Aliza Rosen.
