Measles, mumps and rubella are all viral infections that caused widespread illness. Vaccines are now available for each and have been combined to form the MMR vaccine.
- The diseases
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 2014, more than 600 cases were reported, the largest outbreak in about 20 years. The reason: some parents were choosing not to vaccinate their children.
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°F
- 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
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 his hand in his mouth or nose, he is 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, he or she 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
- 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.
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.
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 chipmunk-like appearance of people infected with mumps is how mumps got its name.
But not all mumps infections were mild. Before the mumps vaccine, mumps was the most common cause of meningitis (inflammation of the lining of the brain and spinal cord). Virtually all children recovered from meningitis, but some were left with permanent deafness. Before the mumps vaccine, mumps was the most common cause of acquired deafness in the United States.
Mumps can also infect testicles and cause a disease known as orchitis. 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 ophthalmologist 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 vaccines
The MMR vaccine contains vaccines that protect against three viral infections: measles, mumps and rubella. It is given as a series of two doses at 12 to 15 months of age and at 4 to 6 years of age.
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. In 1962 (one year before the first measles vaccine was made available in the United States), 3-4 million people were diagnosed with measles, 48,000 were admitted to hospitals and 500 people died.
In 2012, 55 cases of measles were reported to the Centers for Disease Control and Prevention (CDC). While we were on the verge of eliminating measles from the United States, decreases in the use of the MMR vaccine have led to outbreaks. For example, outbreaks during 2011 led to about 220 cases of measles. And in 2014, the United States experienced the largest measles outbreak in about 20 years — more than 600 cases were reported. This outbreak occurred because a critical number of parents had chosen not to vaccinate their children.
What are the side effects of the measles vaccine?
Some children develop soreness in the local area of the shot, and occasionally a low-grade fever. Reports have also indicated rare cases of fevers greater than 103 degrees, usually five to 12 days after receiving the shot. Also some children develop a mild, measles-like rash about seven to 12 days after getting the measles vaccine. Children with this reaction can still get the measles 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 vaccine. This is no longer the case. Studies showed that even children with severe egg allergies could receive the measles 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 daughter of Dr. Maurice Hilleman, a scientist who, at the time, was working in the research laboratories of a company named Merck, Sharpe & 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 (a now 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.)
The strain of mumps virus used in the vaccine is called the "Jeryl Lynn" strain, in honor of Dr. Hilleman's daughter.
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 vaccine. This is no longer the case. Studies showed that even those with severe egg allergies could receive the mumps 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: Rubella 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 vaccinating one person to protect another. We vaccinate girls so that, if they become pregnant as adults, their unborn children will be protected against the devastating effects of rubella virus. 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?
In the early 1990s, a second dose of the MMR vaccine was recommended. This recommendation was made 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.
The other reason that a second dose of MMR vaccine was recommended was to allow for more children to develop a protective immune response. About 95 of every 100 children will develop immunity after one shot, but about 99 of 100 children will develop immunity to measles after two shots. Immunizing that additional 4 percent of children is important when trying to protect against a disease as highly contagious as measles.
The addition of mumps and rubella vaccines in this recommendation increases the percentage of children who develop immune responses to those viruses as well.
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 virus infection.
Do people older than 50 years of age need a mumps vaccine during an 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 okay 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 immuno-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?
Yes. A person can find out if he or she has developed an immune response to each of the three diseases that the MMR vaccine prevents (measles, mumps and rubella) by getting a blood sample drawn. A clinical laboratory can then check for the presence of antibodies for each of the diseases.
However, if there is a question about immunity, doctors typically will recommend receipt of the vaccine rather than prescribing the blood test first. 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 individual immunity should be discussed with your healthcare provider, so that individual situations can be handled most appropriately.
Is the MMR vaccine available as individual components?
The MMR vaccine is not available as individual components in the United States. 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 purported 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 the measles vaccine outweigh its risks?
Measles was almost eliminated from the United States. 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. Because the measles vaccine has no serious permanent side effects, its benefits still clearly outweigh its risks.
Do the benefits of the mumps vaccine outweigh its risks?
In 2009 and 2010, a mumps outbreak that started at a summer camp affected more than 1,500 people. In 2012, the Centers for Disease Control and Prevention (CDC) received reports of about 200 cases of mumps. Because the mumps virus has the potential to infect the brain and cause permanent deafness, and the mumps vaccine does not have serious side effects, the benefits of the mumps vaccine outweigh its risks.
Do the benefits of the rubella vaccine outweigh its risks?
In 2012, eight cases of rubella were reported to the CDC and three babies were born to women infected with rubella before coming to the United States. One of the three babies died, and the remaining two will live with permanent disabilities. Rubella has been virtually eliminated from the United States; however, it is still quite common in many other regions (for example, China and Bangladesh). Because the rubella vaccine does not cause serious, permanent, side effects, the benefits of the rubella vaccine still 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)
- 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, and Offit PA. Measles vaccines in Vaccines, 6th Edition, 2012, 352-387
- Plotkin SA, Orenstein W, and Offit PA. Mumps vaccines in Vaccines, 6th Edition, 2012, 419-446
- Plotkin SA, Orenstein W, and Offit PA. Rubella vaccine in Vaccines, 6th Edition, 2012, 688-717