The current measles outbreak might make you wonder whether you need a booster vaccine.

If you’re fully vaccinated—meaning you have received two doses of the MMR (measles-mumps-rubella) vaccine—you likely don’t need another dose, said William Schaffner, MD, an infectious disease specialist at Vanderbilt University in Nashville and a spokesperson for the Infectious Diseases Society of America.

Most, though not all, childhood vaccinations offer lifetime protection, Schaffner added. However, if you’re worried that you may have missed a vaccine or a dose, you should reach out to your primary doctor to discuss your options. Local and state health departments can also answer questions about any need for boosters. 

If you don’t have access to your immunization records, you can get a blood test to find out the level of antibodies you have for measles or any other infectious diseases.

Here’s what infectious disease experts say about the common routine childhood vaccines and if you should consider getting a booster.

1. MMR Vaccine (Measles, Mumps, and Rubella)

Generally, Schaffner said, anyone born before 1957 is assumed to have had measles and, therefore, is fully protected.

The current measles vaccination recommendation for children is two doses, one between 12 and 15 months and one between ages 4 and 6. The measles vaccine is given as part of a combination shot known as the MMR vaccine, which also protects against mumps and rubella.

However, even if you were vaccinated against measles as a child, you may not be fully protected if you got the MMR vaccine during certain years. The version administered between 1963 and 1967 was not as protective as the current one, and between 1968 and 1989, the recommendation was for just one dose.

If your vaccine record only shows one MMR shot, you should talk to your doctor about whether you need a second, Schaffner said.

The Texas Health Department is advising people who don’t know their measles vaccination status but were exposed to someone with measles to get an MMR vaccine within three days of exposure.

There’s mixed evidence on whether the shot will prevent measles after exposure, but limited evidence shows that it could make the case less severe, said Jose Lucar, MD, an infectious disease specialist at the George Washington University School of Medicine and Health Sciences.

For people who are immunocompromised, such as people with HIV, organ transplant recipients, or someone receiving cancer treatments, they should discuss with their doctor about the need for boosters, Lucar said. Since the MMR vaccine is made from a live virus, those with compromised immune systems could be at risk of contracting the virus. This is why health authorities are urging people who can get vaccinated to do so now.

“When immunization rates are high, people who cannot be protected directly by vaccines are protected because they are not exposed to the disease,” Bruce A. Scott, MD, president of the American Medical Association, said in a statement.

2. Chickenpox Vaccine (Also Called Varicella)

According to the CDC, people 13 years and older who have never had chickenpox or received a chickenpox vaccine should get two doses, separated by 28 days. If you’ve only had one dose when you were a child, you should also get a second dose.

Regardless of whether you’ve been vaccinated against chickenpox, once you turn 50, you should consider getting Shingrix, a two-dose shingles vaccine. Shingles is a painful rash that is caused by the reactivation of the chickenpox virus. It can happen years after someone has recovered from chickenpox or received the chickenpox vaccine.

The chickenpox vaccine is not recommended for unvaccinated people who are immunocompromised, pregnant people, or those who recently had a blood transfusion.

3. Tetanus Vaccine (TDaP or DTaP)

A tetanus booster (known as TDaP for adults and DTaP for kids) is recommended every 10 years or after an injury such as a puncture wound if you don’t know when you last got the vaccine.

The TDaP also protects against diphtheria and pertussis (whooping cough). The need to get a booster sooner than 10 years because of a diphtheria outbreak hasn’t happened in close to two decades, and that was in the former Soviet Union, Schaffner said.

For whooping cough, the effectiveness of the combination vaccine wanes after several years, said Shira Doron, MD, chief infection control officer at Tufts Medicine in Boston and a spokesperson for the Infectious Diseases Society of America.

A booster isn’t broadly recommended sooner than 10 years, Doron explained, but doctors may suggest one for people in close contact with infants younger than two months if it has been a few years since their last TDaP shot or if their vaccination history is unknown. Infants don’t get their own pertussis shots until two months old, and contracting the virus before then can cause severe illness and even death.

Can You Get Booster Vaccines for Free?

If your doctor recommends a vaccine booster dose, you may want to check with your private insurer or Medicare to see if the shot is covered.

If not, and it’s a local or statewide recommendation, chances are the health departments will provide the shot for free. In Texas, for example, the U.S. Department of Health and Human Services has arranged for thousands of measles vaccines to be given free of charge.

Under the Affordable Care Act (ACA), private insurers and Medicare must cover vaccines, including boosters, if they’re recommended by the Advisory Committee on Immunization Practices (ACIP), which advises CDC on immunization schedules, said Josh Michaud, associate director for Global Health Policy at KFF.

For example, the committee recommends a TDaP booster every 10 years, and a dose after an injury may be covered as treatment. Without the recommendation, private insurers can decide whether to offer coverage or not, Michaud said.

A late February ACIP meeting was postponed with no reason given. The committee had planned to discuss recommendations for a new meningitis vaccine and an at-home nasal flu vaccine.”

If the CDC recommends a vaccine without an ACIP recommendation, then it’s unclear “what private insurers might be required to do in terms of coverage,” Michaud said. “The implications for coverage under the ACA are not entirely clear.”

What This Means For You

If you’re uncertain about your vaccination history, use your next doctor visit as an opportunity to discuss immunization needs and options. Staying informed and vaccinated is key to personal and community health.