Measles was surging in West Texas as Nancy Churnin eagerly awaited the birth of two grandchildren. She was sure she had been vaccinated decades ago, but she wanted to confirm she was still protected.
She didn’t want to risk spreading the highly contagious disease to vulnerable newborns, so she got a simple blood test last year.
“I wanted to double-check my immunity,” said Churnin, a children’s book author who lives in Plano, Texas, near Dallas.
Churnin is among more than 74,000 U.S. adults over age 50 who have received blood tests checking their measles antibody status from January 2025 through March of this year, according to an exclusive analysis of medical records data conducted in response to questions from Healthbeat.
The rates of older adults seeking measles immunity tests spiked across the country during last year’s West Texas measles outbreak and again earlier this year as South Carolina’s measles outbreak became the nation’s largest in decades, according to the analysis by a research team at Truveta, a healthcare data and analytics company that receives patient care data from major health systems that serve about one in three U.S. residents.
Truveta’s research team said its analysis suggests that public awareness of high-profile local measles outbreaks might be influencing more people across the country to seek the immunity tests, which are called titer tests.
Nina Masters, the principal applied research scientist at Truveta who led the analysis, said she was struck by the spikes in titer testing during outbreaks because historically, the standard recommendation has been to just vaccinate people who don’t have proof of immunity.
“To me, that suggests outbreaks are influencing healthcare-seeking behavior and reflects growing concern among Americans who want to understand their immunity status and protect themselves and their loved ones amid rising measles activity,” said Masters, a former Centers for Disease Control and Prevention epidemiologist who has deployed to multiple measles outbreaks.
As the U.S. is poised to have another record year for measles, people who are infected are increasingly exposing others to the virus in a wide range of public settings from schools and churches to restaurants, stores, and airports. The virus spreads through the air and can linger in a room for two hours after the infectious person has left, putting anybody who goes through the area at risk if they lack immunity.
The result is large numbers of people need to quarantine at home for up to 21 days if they are not vaccinated against measles or cannot provide proof of their immunity through previous vaccination or illness.
“We think it’s important for people to know their immunity status,” said Dr. Emma Doran of the North Carolina Department of Health and Human Services, which recommends titer tests as one of the ways people can check their immunity before they are exposed.
Titer tests can be particularly helpful for older adults who were vaccinated against measles long before electronic medical records and state immunization registries and no longer have their paper vaccination records. The measles vaccine provides lifelong immunity for most people. Two doses of the combination measles-mumps-ruebella shot is 97% effective against measles, and one dose is 93% effective.
“There is a good chunk of the population there that, unfortunately, if somebody didn’t hold on to that paper, they don’t have it,” said Doran, who is the medical director of the department’s Vaccine Preventable and Respiratory Diseases Medical Consultation Unit.
Immunity tests spiked in U.S. during Texas, South Carolina outbreaks
The new data on titer testing provides a window into one of the many ways the return of measles in the United States is impacting people’s lives. The disease was declared eliminated from the country in 2000. In November, an international public health body will review whether the disease has once again become endemic to the United States.
During 2025 — as a major measles outbreak was underway in West Texas — more than 62,000 older adults across the country went to doctors’ offices to get measles titer tests, the Truveta analysis found.
The surge in testing was dramatic, and not just in Texas.
Nationwide, adults 50 and older received measles immunity testing last year at nearly seven times the rate they had in recent years. From 2021 through 2024, a typical month saw about 50 people get tested for measles immunity for every 100,000 adults who had an outpatient doctors’ visit. But in 2025, that figure reached nearly 341 tests per 100,000 adults.
The rate of titer testing within the state of Texas was particularly high, peaking at 627 tests per 100,000. But even when data from Texas was excluded, the data for the rest of the United States still showed a spike in testing at nearly 309 tests per 100,000.
A similar pattern played out during the first three months of this year, when more than 12,000 U.S. adults over 50 received titer tests as the South Carolina measles outbreak became the nation’s largest in 35 years. The analysis showed an even larger spike in testing rates in 2019, when measles outbreaks also fueled an earlier record number of cases.
The analysis involved an examination of electronic health record data from nearly 30 million patients over 50 who had outpatient visits from January 2018 through March. The data is provided to Truveta by the company’s health system members. The researchers looked at data for older adults to try to focus on those seeking the tests long after childhood vaccination or illness, as well as to reduce the inclusion of routine prenatal testing.
Truveta conducted the analysis after Healthbeat asked the company whether its data could provide any information about whether more people were seeking titer tests amid the recent measles outbreaks.
While the data does not say why the individuals received measles titer tests, Masters and her research team said the spikes in titer testing during outbreaks likely reflect a combination of patient concern, vigilance by healthcare providers, exposure-related evaluations, and adult uncertainty about immunization status. Media coverage might also play a role.
There could be many reasons why an adult might want to check their immunity amid increased spread of measles, the researchers said. They include grandparents seeking to confirm they are protected before visiting infant grandchildren, as well as adults who are worried about the risk of living in or traveling to an outbreak area.
Protecting her newborn grandbabies was Nancy Churnin’s motivation in getting a measles titer test last year before they were born. The babies’ parents were also seeking to safeguard their infants against infectious diseases.
“Anybody who wanted to see the baby was on notice: Get all your shots or we can’t let you around the baby unless you’re fully, fully vaccinated,” recalled Churnin.
When Churnin’s titer test result came back, she was surprised to learn she was not immune to measles. She was certain she had been vaccinated as a child, but she was born in 1957 and she has no access to her records, and her parents aren’t around to ask. After the test, she got vaccinated.
“I was very, very glad I got the test. I’m very, very glad I got immunized,” Churnin said. “I don’t want to do anything to endanger those babies, anybody’s babies.”
Should you get a Titer test? Cost, doctors' views shape decisions.
Most older adults are likely to be protected against measles either because they were vaccinated as children or had the disease before vaccines became available.
Adults born before 1957 are officially presumed to be immune to measles because they were likely infected when they were children, according to the Centers for Disease Control and Prevention. Vaccines against measles have been available in the United States since the early 1960s, with an improved version of the vaccine distributed since 1968.
Should those who can’t find their vaccination records ask their doctors for titer tests?
The CDC recommends that adults born during or after 1957 who can’t find their immunization records get the MMR vaccine. But the CDC guidance also says they can get a measles titer test to determine if they need the vaccine. “There is no harm in getting another dose of MMR vaccine if an individual may already be immune,” the CDC says.
There are several factors to consider in whether to do a titer test or just get another MMR shot, experts said.
Dr. Margot Savoy, chief medical officer of the American Academy of Family Physicians, told Healthbeat that it’s not common for patients to ask for a titer test unless they work in a healthcare field where the test is required.
“The question that they normally ask is: How do I know if I’m protected?” she said.
“For most family physicians, and most physicians in general, their answer would be, I don’t know that I would draw titers on most people. If we’re at all worried that you might not be protected, we would just give you another MMR” vaccine, she said.
Savoy said the time and cost of getting a titer test is not worth it for the average patient, because the test may show the person needs to get vaccinated anyway.
Unlike the MMR vaccine, which is routinely covered by insurance plans without patient cost-sharing, there are no requirements for insurance coverage of titer tests, although insurers can choose to cover them. In addition to getting the tests through a doctor’s office, many direct-to-consumer labs and walk-in clinics also will do the tests without a prescription, but the costs can range from $40 to $150 or more.
Individual patients may weigh the costs and benefits differently when deciding between just getting an MMR shot or getting tested, said Doran.
“I think there’s no one-size-fits-all approach for whether to do an MMR vaccine if you don’t have the records or whether to get a titer first,” she said.
