How many MMR shots are required for adults?

The MMR vaccine protects against measles, mumps, and rubella. It is a crucial vaccine for children, but many adults may be unsure if they need the MMR shot as well. So how many MMR shots are required for adults? The quick answer is that most adults only need 1 or 2 doses of the MMR vaccine. However, the full recommendations depend on your age, job, lifestyle, and a few other factors. Read on to learn all the details on MMR vaccine recommendations for adults.

MMR Vaccine Basics

Let’s start with a quick overview of how the MMR vaccine works. The MMR shot contains weakened forms of live measles, mumps, and rubella viruses. When you get the vaccine, your immune system is activated and makes antibodies against these viruses. That way, if you are ever exposed to real measles, mumps, or rubella in the future, your body is prepared to fight them off more easily. This prevents you from getting sick or reduces the severity of the illness.

The MMR vaccine is given as an injection, usually in the arm. The standard MMR schedule for children is:

  • First dose at 12-15 months old
  • Second dose at 4-6 years old

This 2-dose series is about 97% effective at preventing measles and 88% effective for mumps and rubella. Immunity from the MMR vaccine is thought to be lifelong in most people.

MMR Vaccine Recommendations for Adults

So when do adults need to get the MMR vaccine? Here are the current recommendations from the CDC:

If you were born in 1957 or later:

  • You should have documentation of 1 dose of MMR vaccine, or other acceptable evidence of immunity to measles, mumps, and rubella

Acceptable evidence of immunity includes:

  • Documentation of vaccination with 1 dose of MMR vaccine
  • Lab evidence of immunity or disease confirmation for measles, mumps, and/or rubella
  • Documentation of physician-diagnosed measles or mumps disease
  • Lab confirmation of rubella immunity

So if you do not have proof of receiving at least 1 dose of MMR in your childhood, you should get vaccinated with 1 dose as an adult. Some adults may need a 2nd dose, which is discussed more below.

If you were born before 1957:

  • You are generally considered immune to measles, mumps, and rubella based on your likely exposure to the actual diseases before vaccines were available
  • However, the CDC says those working in healthcare facilities should consider getting 2 doses of MMR vaccine spaced at least 28 days apart due to possible increased risk of exposure

If you work in healthcare:

  • All healthcare personnel should have documented evidence of immunity, including 2 doses of MMR vaccine or other acceptable proof
  • Students entering college/vocational healthcare training programs also need 2 properly spaced doses of MMR
  • Some healthcare facilities may require antibody blood tests to confirm immunity, especially if you do not have documentation of receiving 2 doses of vaccine

The 2-dose MMR requirement for healthcare workers aims to give maximum protection against transmission of measles, mumps, or rubella to vulnerable patients.

If you are a student at a post-high school educational institution:

  • Colleges and other higher education institutions may require full MMR vaccination for incoming students who do not have documented evidence of immunity
  • Contact your specific school to ask about MMR vaccine requirements for enrollment

If you plan to travel internationally:

  • You may need proof of MMR vaccination when traveling to certain countries that still have a high risk of measles circulation
  • Contact the embassy of your destination country or a travel clinic for advice on vaccination requirements for your itinerary

Some countries like Australia and New Zealand require travelers to show they’ve received at least 1 dose of MMR vaccine if over 12 months old.

If you are a woman thinking about pregnancy:

  • MMR vaccination is recommended before you get pregnant, since measles, mumps, and rubella can cause complications during pregnancy for you and your baby
  • Women should wait 1 month after getting MMR before trying to conceive
  • If you find out you’re already pregnant but haven’t gotten the MMR vaccine, wait until after you give birth to get vaccinated

It’s optimal for women to be protected from measles, mumps, and rubella before becoming pregnant. The MMR vaccine is not known to cause harm during pregnancy, but as a precaution it is not given until after delivery.

Who Needs a Second MMR Vaccine Dose?

While 1 dose of MMR offers good protection, there are certain groups who benefit from receiving 2 properly spaced doses for maximum effectiveness.

You should get a second dose of MMR vaccine if any of the following apply:

  • You are entering a healthcare professional training program (medical, dental, nursing school)
  • You work in a healthcare facility
  • You travel internationally where measles risk is high
  • You are a student at a college, university, vocational school, or other higher education institution that requires full MMR vaccination
  • You live in a community experiencing a measles outbreak

And if you received your first MMR dose before 1968, you should get a second dose since the vaccine effectiveness was lower in the early years.

For optimal results, the recommended spacing between 2 doses of MMR is:

  • Minimum of 28 days apart
  • No maximum interval, so any time after 28 days is appropriate

Some adults may end up receiving 3 total MMR doses over a lifetime. This is safe and can help confer additional immunity in high-risk situations like healthcare work.

When Should Adults Without Records Get MMR?

What if you’re an adult born after 1957 but you don’t have childhood immunization records or other proof of MMR vaccination? The CDC says you should:

  • Get 1 dose of MMR vaccine now as an adult
  • Consider a 2nd dose if you are in one of the higher-risk groups mentioned above

Talk to your doctor to confirm whether you need 1 or 2 doses based on your age, job, and health status. Some doctors may decide to just test measles, mumps, and rubella blood antibody levels instead of giving vaccine right away. But in general, the CDC says most adults can safely get at least 1 dose of MMR even if records are not available.

No Harm in Getting Extra MMR Doses

What if you end up getting an extra dose of MMR vaccine by accident? Don’t worry – there is no harm in receiving more than the recommended number of doses. The CDC states that extra doses of MMR provide “no known adverse effects,” so it is not risky if you happen to end up with 3 or 4 lifetime doses due to precautionary vaccinations. An extra dose here and there is not dangerous and simply helps boost your immunity.

Possible MMR Vaccine Side Effects

The MMR vaccine is very safe and effective for most people. Still, mild side effects can occur after vaccination. Common ones include:

  • Fever in about 5-15% of people
  • Mild rash in 5% of people
  • Swollen lymph nodes, especially in the neck and armpit area
  • Joint pain or stiffness
  • Temporary pain or stiffness at the injection site

These symptoms normally start within 6-14 days after getting the shot and clear up on their own within a week or two.

More serious allergic reactions are very rare (about 1 case per million doses) but can include:

  • Swelling of the throat and face
  • Trouble breathing
  • Hives covering the body
  • Dizziness or weakness

If concerning symptoms develop after getting the MMR vaccine, seek medical treatment right away. Also always tell your doctor about any allergies before getting vaccinated.

There is no evidence the MMR vaccine increases the risk of chronic illnesses or disorders like autism. Extensive research and data from millions of doses show the MMR shot is extremely safe long-term.

Why MMR Vaccination Matters

Measles, mumps, and rubella used to be common childhood illnesses before the vaccine was introduced. While they may seem like trivial diseases, they can actually lead to severe complications like:

  • Measles: Pneumonia, seizures, brain damage, deafness, death
  • Mumps: Deafness, meningitis, painful swelling of the testicles or ovaries
  • Rubella: Birth defects like deafness, heart problems, intellectual disability if acquired by a pregnant woman

Routine childhood vaccination has nearly eliminated measles, mumps, and rubella from the United States. However, these viruses still circulate globally. Measles remains common in many parts of the world – an estimated 7 million cases and 600,000 deaths occur each year. That’s why ongoing vaccination is important to control these diseases everywhere.

Even in the U.S., periodic measles outbreaks happen when unvaccinated travelers get infected overseas and return home with the virus. The CDC reports that from January 1 to October 3, 2022, there have been 29 measles cases recorded in the country. While this is low compared to before the vaccine, it shows the importance of maintaining high MMR immunity to prevent outbreaks.

The bottom line is: don’t underestimate how dangerous actual measles, mumps, or rubella can be. Staying up to date with MMR vaccination continues to be essential for protecting yourself and others.


While primarily a childhood vaccine, MMR is important at older ages too. All adults should get at least one MMR vaccine dose if there is no evidence they received it before. Some adults like healthcare workers, college students, and international travelers need two properly spaced MMR doses. An extra dose or two beyond the recommendations is okay and causes no harm if someone ends up getting vaccinated more than required. But the minimum MMR coverage includes 1-2 doses for most adults, unless they were born before 1957. Talk to your doctor to confirm you’ve received this protection against measles, mumps, and rubella. Vaccination continues to be our best defense against the serious complications these viruses can cause.

Leave a Comment