Do I Need A Measles Booster? What Vaccinated Adults Need To Know

There was a time not long ago when Americans lived with confidence that they’d never get measles — before widespread vaccinations, a childhood killer that claimed about 450 lives a year.

Now, measles outbreaks in West Texas and New Mexico, along with growing vaccine skepticism, are causing that confidence to wane, especially among Americans who got vaccinations as kids and believed themselves to be protected for life.

Vaccines introduced in 1963 all but eliminated the disease, and in 2000, the Centers for Disease Control and Prevention declared measles eradicated in the United States. However, measles cases are surging globally prevalent worldwide, according to the World Health Organization.

Measles is a highly contagious respiratory disease, one of the most infectious known, that spreads easily through the air when someone who is infected breathes, sneezes or coughs. In addition to coughing and sneezing, fever and the distinctive measles rash are common symptoms. =

Measles is dangerous at any age, according to the CDC, but some vulnerable populations are likely to suffer from severe complications. They include:

• Children younger than 5;
• Adults older than 20;
• Pregnant women; and
• People with weakened immune systems, such as from leukemia or HIV infection.

Here’s what you need to know:

Where Are U.S. Measles Cases?

In the United States, 378n people have been infected with measles so far this year, according CDC surveillance data updated Friday.

The cases are in 18 jurisdictions, primarily Texas and New Mexico, but also Alaska, California, Florida, Georgia, Kansas, Kentucky, Maryland, Michigan, New Jersey, New York City, New York State, Ohio, Pennsylvania, Rhode Island, Vermont and Washington.

Do Adults Need A Booster?

Adults who have “presumptive evidence of immunity” generally don’t have to get a measles booster shot. Criteria include written documentation of vaccinations earlier in life, lab confirmation of a previous infection or being born before 1957, when most people were likely to be infected naturally.

People who were vaccinated years ago but who are at high risk for infection may want to consider getting a booster if they live in an area with an outbreak, Scott Weaver, with the Global Virus Network, an international coalition, told The Associated Press.

Those individuals may include family members living with someone who has measles or those especially vulnerable to respiratory diseases because of underlying medical conditions.

What Groups Should Consider Booster?

Adults who may want to talk to their doctor about a booster include those born after 1957 and vaccinated before 1968, when more effective vaccines were introduced.

Protection provided in the initial single-dose inactivated measles vaccine was found to fade over time, so it was switched to the two-dose live-attenuated vaccine that is still used today.

People who are in regular contact with people who aren’t eligible for the measles vaccine — for example, people who are immunocompromised and pregnant women — may want to consider getting a booster, according to infectious disease experts.

Where Can People Find Vax Status?

States keep vaccine records specifically for this reason. Anyone can look up their or their kids’ records. High schools and colleges may still have vaccine records for their alumni. People’s childhood pediatrician offices are a good place to look, too.

Are Antibody Tests Recommended?

Most people don’t need to take a titer test, which checks the level of antibodies in a person’s blood, according to Dr. Daniel Pastula, a neurologist at the University of Colorado Anschutz Medical Campus, said in a Q&A with The Conversation.

The problem, Pastula explained, is that the level of antibodies in a person blood doesn’t necessarily reflect the level of immunity. They’re just part of the immune system’s infection-fighting force. Having a low level of antibodies does not necessarily mean your immunity has waned.

“Other crucial elements of your immune response include B cells, T cells and other immune cells, but a titer test does not show their capabilities,” he said. “For example, memory B cells might not currently be making antibodies against the virus but are primed to quickly do so the next time they see it. This is why antibody and titer tests should be used only in specific cases, in consultation with your doctor.”

Can The Vaccine Cause Measles?

Getting vaccinated won’t cause measles because it contains a significantly weakened strain that has limited ability to infect and damage cells, Pastula said.

The CDC and Texas Department of State Health Services debunked claims the outbreak in Texas was caused by the vaccine.

Researchers classify measles virus strains based on their genetic characteristics, or genotypes, and they identified the outbreak virus as wild type genotype D8, and not the weakened measles vaccine strain, which is genotype A, Pastula said.

There is some risk of a mild, measles-like syndrome that may cause some people to have a slight fever, a rash or slight joint pain, he said. Most people have no symptoms after getting a vaccination. Among those who do, they usually go away in a couple of days.

Is Public Confidence Slipping?

The health policy research, polling and journalism organization KFF found in a January tracking poll that while a large majority (80 percent) of the public continues to believe the benefits of MMR vaccines outweigh the risks, about 1 in 5 felt the opposite.

Trust in the measles shot was lower among parents, with 7 in 10 saying the benefits outweigh the risks.

The poll also found that 63 percent of adults overall and 67 percent of parents said they’d heard false claims that MMR vaccines cause autism, a widely debunked claim of Health Secretary Robert F. Kennedy.

Just 3 percent said the false claim is true, but only a third said it is “definitely false.” The rest are somewhat uncertain what to believe, with 20 percent saying the claim is “probably true” and 41 percent saying it is “probably false.”

In the poll conducted Jan. 7-14 in the final days of the Biden administration, less than half of respondents trusted at-the-time President-elect Donald Trump (42 percent) and Kennedy (43 percent) to make the the right public health recommendations.

Overall, the KFF poll found the public’s trust in the information from key health agencies over the past 18 months continued to slide, a trend that began during the COVID-19 pandemic.

Among other findings:

• Two-thirds of respondents said they trust the scientists at the National Institutes of Heath.
• Just over half (53 percent) of respondents said they have at least “a fair amount” of trust in the Food and Drug Administration to make the right decisions about health issues, down from nearly two-thirds (63 percent) in June 2023.
• Trust in health recommendations from the Centers for Disease Control and Prevention also dipped slightly to 61 percent, down from 66 percent in the 2023 survey.

Importantly, the poll skews heavily along party lines on most questions. Dive in for more information on the KKF website.

What’s Happening In Washington?

Kennedy cancelled key vaccine meetings in one of his first acts of health secretary, and this week, at Kennedy’s direction, the National Institutes of Health began canceling funding for some research on vaccines.

At the same time, the CDC is preparing to research autism and vaccines, planning to “leave no stone unturned in its mission to figure out what exactly is happening,” HHS spokesman Andrew Nixon said in a statement.

Multiple studies have concluded there is no link between the two, which the CDC states on its website. Studying it again could take resources away from other research, including finding the cause of autism, Sen. Bill Cassidy, a Louisiana Republican, said as he questioned National Institutes of Health director nominee Dr. Jay Bhattacharya.

When Bhattacharya suggested more studies could be worthwhile because some may believe there’s a link, Cassidy retorted: “There’s people who disagree the world is round.”

Dr. Paul Offit, an FDA vaccine adviser and infectious disease doctor at Children’s Hospital of Philadelphia, told The Associated Press that Kennedy is trying to create a “scare about the safety of vaccines.”

“It shouldn’t surprise anybody,” Offit said. “His agenda has always been to get vaccines off the market, or to make them less available.”

Since his confirmation, Kennedy has repeated his skeptical views of vaccines in interviews and other public statements.

He's sent “mixed messages” on vaccine safety, even though the U.S. has “the most elaborate vaccine adverse event surveillance system in the world,” Dr. William Schaffner, an infectious disease expert at Vanderbilt University, told The AP

Serious problems, including death, are very rare and the benefits of vaccination far outweigh the risks, he said.

“A simple way to describe this to the average person is the serious adverse events generally occur at a rate of 1 to a few cases per million doses of vaccine,” he said. “That’s a needle in a haystack.”

The Associated Press contributed reporting.