Data from large meta-analyses show that measles vaccination is highly effective and safe, reducing the chances of getting measles by 95%.
In the past, nearly every child was infected with measles. This frequently led to health complications, and for many children, the illness proved fatal.
But that changed dramatically with the arrival of the measles vaccine. Widespread vaccination means that measles has become rare in many countries, and over ninety million lives have been saved by measles vaccinations in the last fifty years. It’s estimated that 2 to 3 million people globally would die from measles every year if vaccines weren’t available.1
However, the safety and benefits of these vaccines are still debated in public discussions. How well does the measles vaccine work? What are the risks? It’s common to want clear answers about health, especially for children.
In this short article, I summarize the scientific evidence on the effectiveness and side effects of the measles vaccine.
The data shows that just one dose cuts the chances of measles by about 95%, and two doses do even better.
Side effects, like a mild fever or rash, do happen but are usually minor and short-lived. More serious reactions can occur, but these risks are rare and less likely than if the child actually got measles. It’s also important to be clear about what isn’t linked to the vaccine. The comprehensive evidence we have shows no association with autism, developmental delays, brain damage, or other conditions like asthma or diabetes.
Individual studies can be hard to interpret on their own — their results can vary widely depending on the study’s size, design, or context. That’s why researchers often turn to large, systematic reviews that combine many studies to get a clearer picture.
One trusted source for this kind of analysis is the Cochrane Database, a collection of systematic reviews that evaluates health evidence using transparent methods. A major review published there analyzed data from 138 studies conducted between 1971 and 2019, covering more than 23 million children in total, which helps researchers to detect even rare side effects.2
The chart below summarizes their results. Each row represents a particular outcome, such as the chances of measles, asthma, autism, or fevers after vaccination.
The dot shows how much more or less likely that outcome is among vaccinated children. Dots in blue, on the right side of the chart, mean that the result is less likely among vaccinated children. Dots in red, on the left side, mean that they are more likely among vaccinated children.
In gray are the outcomes that have no demonstrated link to vaccination in the comprehensive data.
(This chart compares health outcomes between vaccinated and unvaccinated children, but it does not compare the risks of vaccination to the dangers of getting measles itself, which can be much more severe. That distinction is important to keep in mind.)
One dose of the vaccine reduces the chances of getting sick with measles by around 95%
One dose of the MMR vaccine (the combined vaccine against measles, mumps, and rubella) reduces the chance of getting measles by around 95%.3 This means the chances were twenty times lower in the vaccinated. This is shown in the top panel of the chart.
After two doses of the vaccine, the chances were twenty-five times lower than in unvaccinated children. Two doses are usually recommended because some children who don’t respond to the first dose become protected after the second.2
The vaccine also helps prevent measles from spreading within families and communities. If someone has been exposed to the virus, such as when a family member is infected, getting vaccinated soon can reduce their chances of getting sick with measles by around 85%.4
Fevers and mild rashes are common reactions to the vaccine, but serious side effects are rare
Like any medicine or vaccine, the measles vaccine can cause side effects. In this case, the most common ones are fever and mild rashes.
The chart shows how vaccination is related to side effects. You can see that fever and rashes are shown in red, indicating that they’re more common in vaccinated children. They’re about two times more common after vaccination.
About 1 in 1,500 children have a brief seizure after vaccination — this is a brief spasm, often preceded by a fever, which can last a few minutes. 2–5% of all children have a brief seizure like this at some point during their childhood, typically when they are infants.5 You can watch a brief video by the British Red Cross to see what this looks like and how to respond to it.6 While this can look frightening, it resolves quickly and is not associated with long-term health effects.7
These are about 2 times more common after measles vaccination.2 Vaccination is an uncommon cause of a seizure in children, as most are caused by viral infections.8
Another rare potential side effect is a temporary disorder called idiopathic thrombocytopenic purpura (ITP), which reduces the body’s ability to stop bleeding and is treated with blood transfusions and medications. It is temporary, resolving in less than six months in most children affected.9
Around 1 in 40,000 children vaccinated develop this disorder, but it’s actually more likely after a measles infection (1 per 20,000 cases).2
In the chart, which compares vaccinated versus unvaccinated children — regardless of whether they have been infected — you can see the odds of ITP are twice as high among vaccinated children as unvaccinated children. That’s because large-scale vaccination made measles outbreaks uncommon during this period, and only a very small fraction of children were infected.
The review found no link between the MMR vaccine and many conditions (shown in gray). This includes autism, brain damage, and long-term conditions like asthma, diabetes, and developmental delays.2 Comprehensive data shows that children who are vaccinated have similar rates of autism and other conditions as children who are not vaccinated.
Some people are generally not recommended to get the MMR vaccine:
- Babies under six months: They are still protected by antibodies from their mother, which wear off after a few months, but don’t respond to MMR vaccines.
- People with weakened immune systems: Those undergoing chemotherapy or with severe HIV/AIDS may be at risk of complications from live vaccines.
- Pregnant women: The MMR vaccine is generally not recommended during pregnancy, although studies have found that accidental vaccination does not harm the baby.10
These individuals depend on protection from “herd immunity”. When enough people are vaccinated, the measles virus can’t spread easily, helping protect those who are most at risk.
Add up all of these individuals — babies, immunocompromised people, pregnant women, and individuals undergoing treatments like chemotherapy — and there’s little room for other people to opt out of vaccination while still receiving protection from the community.
Keeping vulnerable people protected depends on high levels of vaccination across the population.11
In short, the measles vaccine is one of the best tools we have to protect public health. Like all medicines, there can be a risk of side effects, but the benefits far outweigh them: both for individuals and the community as a whole.
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Saloni Dattani (2025) - “How effective and safe are measles vaccines?” Published online at OurWorldinData.org. Retrieved from: ' [Online Resource]BibTeX citation
@article{owid-measles-vaccine-effectiveness-safety,
author = {Saloni Dattani},
title = {How effective and safe are measles vaccines?},
journal = {Our World in Data},
year = {2025},
note = {
}
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