Measles vaccines that were given a long time ago could now be less effective, say doctors

For those who were vaccinated for measles many decades ago, there is the possibility that protection has now been worn out.

In the middle of the current measles outbreak in West texas -and with cases that have also been reported in New Mexico, New Jersey and several other countries -some doctors warn of the possibility that Legacy vaccines become less effective over time.

Measles is a very contagious virus for those who have not been infected or vaccinated before, with a probability of transmission of up to 90%.

Measles cases continue to spread in several conditions after the child’s death

The measles vaccine was first introduced in 1968. Three years later, in 1971, the MMR vaccine made its debut and provided a trifecta of protection against measles, mumps and rubella.

Some doctors warn of the possibility that Legacy vaccines will become less effective over time. (IStock)

A few decades after the MMR vaccine was released, measles was declared in the United States in 2000.

“The standard of health authorities such as the CDC is a two-dose series of the MMR vaccine,” said Dr. Nicole Saphier, medical employee of Fox News, to Fox News Digital.

“For most people, these two doses offer lifelong immunity – about 97% effectiveness against measles.”

Who needs another vaccine?

According to Saphier, who practices in New York, the question of whether someone should get another measles vaccine depends on a few factors, e.g.

“If you are an adult who got both cans as a child, you are probably okay unless you are in a group with a high risk z.

“Adults who were vaccinated between 1963 and 1968 for measles should check their vaccination history.”

People who were born before 1957 probably have natural immunity, since according to the doctor, they were probably exposed to measles before the vaccines were available.

“Adults who were vaccinated for measles between 1963 and 1968 should check their vaccination history to determine which vaccine they have received,” said Saphier.

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“During this time, a version of the vaccine that used an inactivated form of the virus that was not so effectively found and was ultimately withdrawn.”

Studies show that antibody mirrors can drop for decades, but actual measles cases with fully vaccinated people rarely remain, Saphier added.

Studies show that antibody mirrors can drop for decades, but the actual measles cases in fully vaccinated people remain rare. (IStock)

“No hard data say that people routinely need a third shot, but if you are worried, a blood test can check your antibody mirror,” she said.

“As with everything in medicine, there is rare risks for vaccination and considerable risks not to vaccinate.”

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The situation of every person is different and should be carefully weighed after a thorough conversation with a trustworthy medical team, added Saphier.

Dr. Marc Siegel, Clinical Professor of Medicine at the Nyu Langone Medical Center and a medical employee of FOX News, also emphasized how important measles vaccinations are – “especially with the number of circulating measles cases and undermined people who come to the United States at a time at a time when there is a great measles all over the world.”

The measles vaccine was first introduced in 1968. Three years later, in 1971, the MMR vaccine made its debut and provided a trifecta of protection against measles, mumps and rubella. (IStock)

For those who travel to an area in which a measles outbreak takes place, he recommends seeing a doctor for a measles test test and receiving a booster if they have no immunity. (The TITER test measures a person’s immunity level against the virus.)

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“This is not an official proposal yet, but I check measurter in many of my patients, and if they are low, I can give a booster as a precaution,” said Siegel.

MMR is a living virus vaccine and cannot be given to pregnant women or immunocompromised people, according to the doctor.

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So far, a total of 164 measles cases have been reported in the United States in 2025, according to the centers for the control and prevention of diseases (CDC).

A vast majority of those (140) is in Texas. Nine cases were reported in New Mexico, the rest in California, Georgia, Kentucky, New Jersey and Rhode Island.