A Look at Each Vaccine: Measles, Mumps and Rubella (MMR) Vaccine
Vaccines to prevent each disease were first developed in the 1960s and then combined to form the MMR vaccine in the 1970s.
The face of measles
In 1991 the city of Philadelphia was in the grip of a measles epidemic. At the center of the epidemic were two religious groups that refused immunizations for themselves and their children. Children with measles developed high fever; a red, raised rash that started on the face and spread to the rest of the body; and "pink eye." For some, the disease got much worse. Six children in these church groups and three children in the surrounding community died from measles.
By 2000, due to effective use of vaccine, measles was essentially eliminated from the United States. However, in 2019, almost 1,300 cases were reported to the Centers for Disease Control and Prevention (CDC). Of those, 128 people were hospitalized and 61 experienced complications, including pneumonia and encephalitis (inflammation of the brain). This was the largest U.S. outbreak in almost 30 years. The reason: some parents were choosing not to vaccinate their children. Although the number of cases was not as high in subsequent years, each year measles cases have continued to occur in the U.S.
What is measles?
Measles is a disease that is caused by a virus. People with measles may have some or all of the following:
- A fever that gradually goes up to 103°-105° Fahrenheit
- Cough, runny nose, pink eye
- Raised, bluish-white spots inside the mouth
- A rash consisting of red spots, raised in the middle. The rash begins at the hairline and moves to the face and neck before descending downward and outward over the rest of the body
- Lack of appetite
Watch as Drs. Paul Offit and Katie Lockwood from CHOP talk about measles, its symptoms, complications, how it’s spread, what doctors worry about, and more.
How does measles spread?
When an infected person coughs or sneezes, measles viruses are spread in the small respiratory droplets. If a susceptible person breathes in these droplets or touches an infected surface and then puts their hand in their mouth or nose, they are likely to get measles.
How contagious is measles?
Measles is one of the most contagious diseases. In fact, if 100 susceptible people are in a room with someone who is infected, 90 of them are likely to become ill with measles. Further, if someone who has not had measles enters an elevator or other small space up to two hours after an infected person has left, they can still “catch” measles.
Are there complications from measles infections?
Yes. About 3 of every 10 people who get measles will develop complications such as:
- Ear infection
- Encephalitis (swelling of the brain)
- Subacute sclerosing panencephalitis (a disease characterized by progressive neurological deterioration and early death)
- Hemorrhagic measles – includes seizures, delirium, difficulty breathing and bleeding under the skin
- Clotting disorder
Pregnant women who are infected with measles can miscarry, deliver early, or have a low-birth-weight baby. People who are immune compromised are at risk of having prolonged and severe illness.
Measles infections can also pave the way for other bacterial and viral infections — even several years later. This may happen because measles infections can wipe out preexisting immunologic memory cells that protect against other infections, such as influenza. Because this same damage to immunologic memory doesn’t happen following vaccination, the measles vaccine also protects the integrity of the immune system.
What if I suspect measles?
Call your healthcare provider and mention your concern. Because measles is so contagious, providers typically do not want infected patients sharing a waiting room with other patients. This is particularly important for infants who are too young to receive the vaccine.
The face of mumps
Before the mumps vaccine, mumps was the most common cause of meningitis (swelling of the lining of the brain and spinal cord) in children. Virtually all children recovered from meningitis, but some were left with permanent deafness. In fact, before a vaccine was available, mumps was the most common cause of acquired deafness in the United States. The vaccine was developed when vaccine researcher, Maurice Hilleman, isolated mumps virus from his daughter, Jeryl Lynn, when she was 5 years old and became ill with mumps. For this reason, the vaccine strain of virus is referred to as the “Jeryl Lynn strain.”
What is mumps?
Mumps is a virus that usually causes swelling in the salivary or parotid glands, just below the ear, lasting for about seven to 10 days. The swelling may occur on one or both sides of the face, causing a chipmunk-like appearance in infected people. This may be accompanied by muscle aches, fatigue, lack of appetite, headache and low-grade fever.
While many mumps infections are mild, not all are. Mumps can infect testicles, causing a disease known as orchitis in up to 1 of every 3 infected males. Some men with orchitis were found to be sterile after the infection resolved. Additionally, mumps infection during pregnancy occasionally resulted in the death of the unborn child.
The face of rubella
Before the rubella vaccine, children infected with rubella would develop a light, mild rash on the face. Some children would also develop swelling of the lymph glands behind the ear. Rubella was a mild infection of childhood. But in 1941, an Australian eye doctor made a curious observation. He found that many children were born with congenital cataracts and blindness following an outbreak of rubella. This was evidence that rubella could permanently damage the developing fetus.
What is rubella?
Rubella is a viral infection, also known as German measles. Rubella infection of children causes a mild rash on the face, swelling of glands behind the ear, occasionally a short-lived swelling of small joints (like the joints of the hand), and low-grade fever. Children virtually always recover from rubella infection without consequence.
But rubella is not always a mild infection. Before the rubella vaccine as many as 20,000 babies were born every year with birth defects because of the capacity of rubella virus to infect the unborn child. In fact, 85 of 100 women infected with rubella in the first trimester of pregnancy had babies that were permanently harmed. Rubella virus can cause blindness, deafness, heart defects or mental deficits in infants whose mothers were infected early in pregnancy.
While rubella was not typically a severe childhood illness, it could be fatal when pregnant women were infected. Before the vaccine, each year about 20,000 babies were harmed when their mothers were infected during pregnancy. For this reason rubella parties were recommended by pediatricians to ensure that young girls were exposed before they were old enough to become pregnant. Today, with the availability of a vaccine, doctors and parents can be assured that children are becoming immune to these diseases in the safest way possible.
The MMR vaccine contains vaccines that protect against three viral infections: measles, mumps and rubella. MMR vaccine is given as a series of two doses with the first dose at 12 to 15 months of age and the second at 4 to 6 years of age.
Watch as Dr. Offit talks about the safety of the MMR vaccine in the short video below, part of the series Talking About Vaccines with Dr. Paul Offit.
While the MMR vaccine is the only way to be protected against measles, mumps and rubella, this section describes each vaccine component separately.
How is the measles vaccine made?
The measles vaccine is a live, "weakened" form of natural measles virus. To make some vaccines, viruses are "weakened" by a process called "cell culture adaptation" (see How Are Vaccines Made?). "Cell culture adaptation" modifies natural measles virus so that it behaves very differently once it is injected into the body.
Natural measles virus normally grows in cells that line the back of the throat, skin or lungs. Cells are the building blocks of all the different parts of the body, like skin, heart, muscles and lungs. Natural measles virus reproduces itself thousands of times, often causes severe disease, and is passed on to the next person unchanged.
But the process of "cell culture adaptation" changes all of that. Natural measles virus was first taken from someone infected with measles. The virus was then "grown" in cells taken from chick embryos. By growing the virus in chick embryo cells, it became less and less able to grow in human cells. This happened because the genes that tell measles virus how to reproduce itself were changed. Now the virus reproduced itself very poorly.
When this vaccine virus (a now modified form of the natural virus) is put back into the body, it grows very poorly. Whereas natural measles virus reproduces itself thousands of times during natural infection, the measles vaccine virus reproduces itself probably fewer than 20 times. That is why natural measles virus causes illness, but measles vaccine virus doesn't. However, because the measles vaccine virus reproduces itself a little bit, it induces immunity against measles that is life-long. (See how vaccines work.)
The effectiveness of the measles vaccine has been dramatic. Before the first measles vaccine became available in the United States (in 1963), 3-4 million people were diagnosed with measles, about 48,000 were admitted to hospitals and about 500 people died every year.
Decreases in the use of the MMR vaccine have led to increasingly larger measles outbreaks. For example, in 2019, the U.S. experienced the largest outbreak in almost 30 years with almost 1,300 cases reported to the CDC. These outbreaks occurred because a critical number of parents had chosen not to vaccinate their children. While cases of measles decreased during the years of the COVID-19 pandemic, due to fewer opportunities for the virus to spread, a few cases occurred each year and the annual number of cases has again started to increase. Sadly, given that vaccine hesitancy and misinformation remain issues post-pandemic, it is likely that we will continue to see this virus spread.
What are the side effects of the measles vaccine?
The measles vaccine causes some children to develop soreness in the local area of the shot, and occasionally a low-grade fever, after receipt of MMR. Reports have also indicated rare cases of fevers greater than 103 degrees Fahrenheit, usually five to 12 days after receiving the shot. In some children (about 1 of every 3,000-4,000 children), the fever may increase rapidly causing a fever-associated seizure. Known as febrile seizures, these seizures, while scary, do not cause long-term harm. (You can find out more about fever and this type of seizure on the Q&A, Infectious Diseases and Fevers: What You Should Know.”)
Also, some children develop a mild, measles-like rash about seven to 12 days after getting the MMR vaccine. Children with this reaction can still get the MMR vaccine in the future. Children with measles rash from the vaccine are not contagious to other people.
Because the measles vaccine is made in chick embryos, it was once thought that children with egg allergies should not receive the MMR vaccine. This is no longer the case. Studies showed that even children with severe egg allergies could receive the MMR vaccine without consequence.
Rarely, the combination measles-mumps-rubella (MMR) vaccine can also cause a short-lived decrease in the number of platelets that circulate in the body. Platelets are cells that help the blood to clot, such as, for example, after the skin is cut. This reaction occurs in roughly 1 of every 24,000 people who receive the vaccine and has never been fatal.
How is the mumps vaccine made?
The mumps vaccine virus is "weakened" by a process called "cell culture adaptation." (see How Are Vaccines Made?). "Cell culture adaptation" modifies natural mumps virus so that it behaves very differently once it is injected into the body.
Natural mumps virus normally grows in cells of the salivary glands. Cells are the building blocks of all the different parts of the body, like skin, heart, muscles and lungs. Natural mumps virus reproduces itself thousands of times, occasionally causes severe disease, and is passed on to the next person unchanged.
But the process of "cell culture adaptation" changes all of that. Natural mumps virus was first taken from a little girl named Jeryl Lynn Hilleman. Jeryl Lynn was the 5-year-old daughter of Dr. Maurice Hilleman, a scientist who, at the time, was working in the research laboratories of a company named Merck, Sharp & Dohme. Dr. Hilleman then "grew" the virus in eggs. By growing the virus in hen's eggs it became less and less able to grow in human cells. This happened because the genes that tell mumps virus how to reproduce itself were changed. Now the mumps virus reproduced itself very poorly.
When this vaccine virus (now a modified form of the natural virus) was put back into other children, it grew very poorly. Whereas natural mumps virus reproduces itself thousands of times during infection, the mumps vaccine virus reproduces itself probably fewer than 20 times. That is why natural mumps virus causes illness, but mumps vaccine virus doesn't. However, because the mumps vaccine virus reproduces itself a little bit, it induces immunity against mumps that is life-long. (See how vaccines work.)
Outbreaks of mumps continue to occur throughout the U.S. These outbreaks are the result of lower vaccine use as well as waning immunity against the most commonly circulating type of mumps virus. Many recent outbreaks have occurred on college campuses. Between 2014 and 2019, more than 1,000 cases of mumps occurred each year with the peak of over 6,000 cases per year during 2016 and 2017. While numbers decreased beginning in 2020, they have started to slowly rise again as we returned to pre-pandemic activities. Hopefully, they will not return to the frequency seen during the years leading up to the COVID-19 pandemic. During outbreaks, a third dose of mumps-containing vaccine may be recommended for those at increased risk of exposure.
What are the side effects of the mumps vaccine?
After receiving the mump vaccine, children may develop soreness in the local area of the shot, and occasionally a low-grade fever.
Because the mumps vaccine is made in chick embryo cells, it was once thought that children with egg allergies should not receive the MMR vaccine. This is no longer the case. Studies showed that even those with severe egg allergies could receive MMR vaccine without serious consequence.
How is the rubella vaccine made?
Like the measles and mumps vaccines, the rubella vaccine is a live, "weakened" form of natural rubella virus. The rubella vaccine virus is "weakened" by a process called "cell culture adaptation." (see How Are Vaccines Made?). "Cell culture adaptation" modifies natural rubella virus so that it behaves very differently once it is injected into the body.
Natural rubella virus normally grows in cells that line the back of the throat. Cells are the building blocks of all the different parts of the body, like skin, heart, muscles and lungs. Natural rubella virus reproduces itself thousands of times, occasionally causes severe disease, and is passed on to the next person unchanged.
But the process of "cell culture adaptation" changes all of that. Natural rubella virus was first taken from someone infected with rubella. The virus was then "grown" in human embryo fibroblast cells. These cells were first obtained from an elective termination of one pregnancy in England in the early 1960s. These same embryonic cells have continued to grow in the laboratory and are used to make rubella vaccine today. Fibroblast cells are the cells needed to hold skin and other connective tissue together.
By growing rubella virus in human embryo fibroblast cells, it became less and less able to grow in human cells that lined the back of the throat or in cells of an unborn child. This happened because the genes that told rubella virus how to reproduce itself were changed. Now the virus reproduced itself very poorly.
When this vaccine virus (a now modified form of the natural virus) was put back into other children, it grew very poorly. Whereas natural rubella virus reproduced itself thousands of times during natural infection, the rubella vaccine virus reproduced itself probably fewer than 20 times. That is why natural rubella virus causes illness, but rubella vaccine virus doesn't. However, because the rubella vaccine virus reproduces itself a little bit, it induces immunity against rubella that is life-long. (See how vaccines work.)
There is no better example of how weakened the rubella vaccine virus is as compared with natural rubella virus than the following story: MMR vaccine has been mistakenly given to pregnant women during their first trimester more than 1,000 times. No child born to these mothers was affected by the rubella vaccine. On the other hand, of 1,000 women infected with natural rubella infection during the first trimester, 850 will have children with birth defects.
Girls are immunized with rubella vaccine to protect their future children
Rubella vaccine is a unique example of not only vaccinating to protect the vaccine recipient, but also vaccinating one person to protect another. We vaccinate girls against rubella so that, if they become pregnant as adults, their unborn children will be protected against the devastating effects of rubella infection. We vaccinate boys to help stop the spread of rubella in the community.
What are the side effects of the rubella vaccine?
Some children experience soreness in the local area of the shot and a low-grade fever. Children may also develop a mild rash that is not contagious to other children.
The rubella vaccine can also cause arthritis (swelling and pain in the joints) in some women (usually those older than 14 years), but the arthritis is short-lived and doesn't cause permanent harm. The rubella vaccine is also an extremely rare cause of short-lived arthritis in young children.
Other questions you might have
Why do children have to get two doses of MMR vaccine?
Two doses of MMR vaccine are recommended for a few reasons:
- In the early 1990s, a second dose of the MMR vaccine was recommended because outbreaks of measles swept across the United States in the late 1980s and early 1990s. Most of the people who were infected with measles during these epidemics were adolescents and young adults. An investigation of what went wrong found that many people who caught measles had never been immunized. So the primary reason for recommending a second dose of MMR was to give children two chances to get one vaccine.
- Another reason that a second dose of MMR vaccine was recommended was so that more children would develop a protective immune response against measles. About 95 of every 100 children will develop immunity after one shot, while about 99 of 100 children will develop immunity to measles after two shots. Creating immunity in 4 additional children of every 100 is important when trying to protect against a disease as highly contagious as measles.
- The additional dose of MMR vaccine also aimed to stem mumps outbreaks, which were occurring primarily in colleges. In 2006, the ACIP recommended 2 doses of MMR to increase protection against mumps for school-aged children as well as adults at increased risk for mumps, such as college students, health care providers, and international travelers. (In 2018, a third dose was approved for those at increased risk due to their proximity to an outbreak.)
- The second dose of MMR vaccine also increases the number of children protected against rubella.
Should teenagers and adults get the MMR vaccine?
The MMR vaccine should be given to any teenager or adult who has not received two doses of the vaccine or has not had natural measles, mumps or rubella infection.
Do people older than 60 years of age need MMR vaccine during a mumps outbreak?
Not typically. Mumps was so widespread before a vaccine was licensed that anyone born before 1957 is considered to be immune from mumps even if they do not recall having the disease. If you are still concerned, talk to your doctor about the possibility of getting the vaccine.
Is it OK for a 1-year-old to get the MMR vaccine if mom is pregnant?
Yes. The MMR vaccine can be given to children who live with pregnant women or immune-compromised people. While the MMR vaccine contains live measles, mumps and rubella viruses, they are weakened so much that they are not usually transmitted from the recipient to others. Even if the virus was transmitted, it is too weak to cause harm.
Is there a test to prove that the MMR vaccine has worked in an individual?
If there is a question about immunity, doctors will typically recommend receipt of the vaccine rather than prescribing a blood test. This is done for a few reasons. First, a second dose of vaccine will not harm the person and is, in fact, likely to boost any response that developed previously. Second, if the blood work comes back negative, a second needle (and appointment) will be necessary to get the vaccine. Finally, the cost of the vaccine is likely to be similar to that of getting the blood work, so if a vaccine is then necessary, the cost will also be higher when the same could have been accomplished by just administering the vaccine.
Any questions about immunity should be discussed with your healthcare provider, so that individual situations can be handled most appropriately.
What should I do if my child did not get MMR vaccine, and we will be traveling internationally to a place where measles has been reported?
Parents who will be traveling abroad with infants should discuss their trip with the child’s healthcare provider or with a provider at a travel clinic as soon as possible, so that there is enough time to ensure the child is immunized according to recommendations based on the travel itinerary and the child’s age.
Is the MMR vaccine available as individual components?
The individual components of MMR vaccine are not available in the United States. Receiving MMR vaccine, rather than the separate vaccine components, results in fewer shots and office visits. It also decreases the amount of time that the child will be susceptible to these three diseases (measles, mumps and rubella).
The interest in using the MMR vaccine as its individual components was born of the ill-founded concern that the vaccine caused autism. However, the MMR vaccine has been studied by many scientists around the world, and there is no indication that it causes autism, as originally proposed by a doctor from the United Kingdom. This doctor was later found to have falsified data, so he lost his license to practice, and his paper was removed by the journal that published it. His hypothesis has caused much damage; as a result, some parents did not vaccinate their children, and some of those children were hospitalized or died.
Can I contract measles, mumps or rubella from a rash that develops after a child in my care got the MMR vaccine?
No, you cannot pass on the diseases by touching the rash. You could only transmit them to others who are susceptible if you are sick with the diseases. It is likely that you are already immune, either by previously having the diseases or from receiving vaccines. However, if you are unsure about your immunity, check with your doctor.
Relative risks and benefits
Do the benefits of MMR outweigh its risks?
Measles was eliminated from the United States in 2000. However, measles still rages throughout developing countries and is one of the leading causes of death worldwide. In the late 1980s and early 1990s in the United States, low immunization rates against measles were associated with epidemics of measles. About 11,000 people were hospitalized and 120 killed by measles virus. In recent years, we have started to again see outbreaks of measles. In 2019, the U.S. experienced the largest outbreak in almost 30 years, with almost 1,300 cases reported to the CDC.
Mumps virus has the potential to infect the brain and cause permanent deafness. Between 2016 and 2019, the CDC received reports of more than 2,200 cases of mumps each year. Many of these occurred on college campuses.
Each year since 2012, about 10 cases of rubella have been reported to the CDC; virtually all of these occurred in people who were living or traveling outside of the United States. Rubella has been virtually eliminated from the United States; however, it is still quite common in many other regions.
Because these diseases can cause harm or death and because the MMR vaccine does not cause serious permanent side effects, the benefits of the MMR vaccine outweigh its risks.
- Fever, conjunctivitis ("pink eye"), and a red, pinpoint rash that starts on the face and spreads to the rest of the body
- Encephalitis (an infection of the brain), which, in many cases, causes permanent brain damage
- Rarely, subacute sclerosing panencephalitis
- Swollen salivary or parotid glands
- Meningitis (inflammation of the lining of the brain and spinal cord)
- Orchitis (swelling of the testicles)
- Miscarriage during pregnancy
- Mild rash on the face, swelling of glands behind the ear, occasionally a short-lived swelling of small joints (like the joints of the hand), and low-grade fever
- Congenital rubella syndrome when women are infected early during pregnancy (85 of 100 babies of women infected during first trimester)
- Soreness at the injection site
- Low-grade fever (rarely, >103 degrees Fahrenheit between five and 12 days later)
- Thrombocytopenia (temporary decrease in platelets, a blood clotting agent)
- Short-lived arthritis (mainly in adult recipients)
Plotkin SA, Orenstein W, Offit PA, and Edwards KM. Measles vaccines in Vaccines, 7th Edition, 2018, 579-618.
Plotkin SA, Orenstein W, Offit PA, and Edwards KM. Mumps vaccines in Vaccines, 7th Edition, 2018, 663-688.
Plotkin SA, Orenstein W, Offit PA, and Edwards KM. Rubella vaccine in Vaccines, 7th Edition, 2018, 970-1000.
Centers for Disease Control and Prevention. Measles Cases and Outbreaks.
Centers for Disease Control and Prevention. Mumps Cases and Outbreaks.
Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.
You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.