Vaccination Booster for Measles: Which Individuals Need It and Reasons Behind It
Rewritten Article:
- In light of the ongoing measles outbreak in the US, it's essential to understand the best measures to stay protected.
- Health and Human Services Secretary Robert F. Kennedy Jr. has echoed the consensus of experts and medical bodies by endorsing measles vaccination as the most effective defense against infection.
- However, an individual's protection may wane over time, leading to the necessity of a vaccine booster in certain cases.
According to the Centers for Disease Control and Prevention (CDC), as of April 3, 2025, a staggering 1,200 measles cases have been reported across the US, though the actual numbers may be higher.
Of these, 97% of cases occurred in individuals who were either unvaccinated or whose vaccination status remains unknown.
The prevailing wisdom remains that vaccination offers the best protection against measles. United States Health and Human Services Secretary Robert F. Kennedy Jr. has been the latest official to endorse vaccination, stating it as "The best way to prevent the spread of measles."
The vaccine currently in use, the MMR vaccine, protects not only against measles but also mumps and rubella, hence the abbreviation. Kennedy Jr. has also instructed the CDC to "stock pharmacies and Texas-run clinics with needed MMR vaccines and other medicines and medical supplies."
Typically, children receive two doses of the MMR vaccine - one at 12-15 months old and another at 4-6 years old - offering 97% protection against measles. Receiving a single dose provides 93% protection.
What factors contribute to measles infection risk?
People who have had the MMR vaccine are generally protected for life. However, the current version of the vaccine, while improved compared to previous ones, raises the question: Should people who have already received a measles vaccine receive a booster shot for continued protection?
Medical News Today consulted David Cutler, MD, a board-certified family medicine physician at Providence Saint John's Health Center in Santa Monica, CA, to help answer these and other related questions.
Cutler highlighted that "there will remain some uncertainty about the risk posed by measles to any one individual due to several factors." These include:
- the prevalence of measles infections in the community
- the level of immunity achieved by the individual and their community through either prior infection or vaccination
- the vulnerability of the individual to measles infection.
What is a vaccine booster?
So, what is a vaccine booster, and how does it work?
According to Cutler, "A booster vaccine works by re-initiating or enhancing a person's immune protection against measles." It serves as a "reminder" to the body's immune system to remain vigilant against a specific pathogen it has already been trained to combat through the initial vaccination.
Who needs a measles vaccine booster?
The first MMR vaccine was introduced in 1963, but compared to current versions of the vaccine, it had a "weaker" formulation.
If you are an adult who was vaccinated in childhood, the exact time you received the measles vaccine may determine whether or not you would benefit from a booster shot. Other factors that come into play include:
- Adults born before 1957 are presumed immune to measles, as they almost certainly had the disease during childhood.
- Blood tests are available for people who want to clarify their immunity status and determine whether or not they should receive a measles vaccine booster. The recommended test is the Immunoglobulin G (IgG) blood test.
To sum up, "You might need a booster if you are a child who only received one dose of the vaccine, an adult who received the inactivated vaccine, an adult with a higher risk of measles exposure, or anyone whose blood test shows a lack of immunity," said Cutler. "Adults who are certain they never had the disease, never had the vaccine, and have no risk factors posing undue risk from the vaccine should get the measles vaccine."
Is it worth getting vaccinated against measles as an adult?
According to Cutler, "Children generally receive two doses of the measles vaccine." By contrast, "adults at average risk should have at least one dose of the vaccine at some point in their lives."
However, certain social categories may need two doses of the MMR vaccine in adulthood if they have not had the vaccine already, as they may face a higher risk of infection compared to their peers. These include:
- healthcare workers
- people who travel internationally frequently
- and students at post-secondary institutions.
As for individuals who have never been vaccinated against measles and may face health risks from receiving a live virus vaccine - and the MMR vaccine is a live virus vaccine - the decision to get vaccinated should be based on a careful assessment of potential risks and benefits.
"For some people with greater vulnerabilities, balancing risks and benefits can be complicated," Cutler noted. "This is why it's essential to consult your primary care physician regarding whether the measles or any other vaccine may be appropriate for you."
- In certain cases, the protection offered by the MMR vaccine may wane over time, necessitating a vaccine booster to ensure continued immunity against measles, mumps, and rubella.
- A booster vaccine works by re-initiating or enhancing a person's immune protection against measles, similar to a reminder to the body's immune system to remain vigilant against the virus.
- Adults who received the measles vaccine in childhood or adolescence may need a booster shot, especially if they are in categories with a higher risk of infection such as healthcare workers, frequent international travelers, or students at post-secondary institutions.
- The decision to get vaccinated against measles as an adult, or receive a booster shot, should be based on an individual's risk factors, previous vaccination history, and a careful assessment of potential risks and benefits. Consulting a medical doctor is essential to make informed decisions about vaccinations.
