What are the benefits of the MMR vaccine?
The MMR vaccine protects your child against three viruses: measles, mumps, and rubella (German measles).
Many parents now choose the MMRV vaccine instead. MMRV is the same as MMR, except that it also includes protection against the varicella virus, which causes chicken pox.
Before a measles vaccine was licensed in 1963, more than 500,000 cases of measles were reported on average in the United States annually, with about 48,000 hospitalizations and 500 deaths from the disease. There were 220 cases in the United States in 2011 – the highest number since 1997.
Measles has been virtually wiped out in the United States, although a small outbreak is occasionally imported – usually from Europe or Asia – to an unvaccinated population (a group that refuses vaccines, for example) or to people who have received only one dose of the MMR vaccine.
Measles outbreaks are still common in other countries, including Europe. According to the World Health Organization, measles is one of the leading causes of vaccine-preventable deaths in young children. But thanks to the global effort to vaccinate children against measles, the number of measles deaths around the world has dropped by 78 percent since 2000.
Mumps is a viral infection that typically causes a fever, headache, and inflammation of the glands under the ears or jaw.
Mumps can lead to meningitis, encephalitis, and (rarely) deafness. It can also cause painful swelling of the testicles or ovaries.
Twenty to 50 percent of males infected with mumps after puberty develop orchitis, an inflammation of one or both testicles. In rare cases, orchitis leads to sterility.
Before a vaccine was available, mumps was common in babies, children, and young adults. The current vaccine was licensed in 1967. By 2009, the two-dose childhood vaccine had reduced the rate of the disease by 99 percent.
But since then, there have been two major outbreaks. In 2006, more than 6,500 cases were reported to the Centers for Disease Control and Prevention (CDC) during an outbreak that mostly involved Midwestern college students living in dormitories. The largest outbreak since 2006 began in July 2009 in New York and New Jersey when a boy brought the illness back from a visit to the United Kingdom.
Rubella, also called German measles, is characterized by a pinkish red rash that starts on the face, a mild fever, and swollen lymph nodes. It's possible, however, to have rubella without any symptoms.
Rubella is a mild illness that runs its course in about three days. But if a woman gets rubella during pregnancy, it can cause a miscarriage or birth defects in her baby, including deafness, eye problems, heart defects, and intellectual disability. During an epidemic in 1964 through 1965, 12.5 million cases of rubella were reported in the United States, and 20,000 infants were born blind, deaf, or mentally disabled as a result.
The first rubella vaccines were licensed in 1969. Today rubella has been virtually eliminated in the United States, with only a handful of cases reported each year.
What's the recommended schedule?
Recommended number of doses
- Between 12 and 15 months
- Between 4 and 6 years old (Although the second dose can be given at any time as long as it's at least 28 days after the first.)
Who shouldn't get the MMR vaccine?
A child who has ever had a life-threatening allergic reaction to gelatin (yes, the stuff found in Jell-O), the antibiotic neomycin, or a previous dose of the MMR vaccine should not get the immunization.
Check with your doctor about giving the MMR vaccine to your child if he:
- Is taking steroids
- Has a disease that affects his immune system, like HIV/AIDS or leukemia
- Has cancer
- Has a blood disorder or has recently received a blood transfusion
Because the measles and mumps vaccines are made by growing the virus in the cells of chicken embryos, children with egg allergies used to be advised not to get the vaccine. However, studies have found that even children with severe egg allergies can receive this vaccine without a greater risk of side effects.
Kids who are moderately or severely ill are usually advised to wait until they're better to get the vaccine.
Who shouldn't get the MMRV vaccine?
The CDC recommends that children with a history of seizures get the MMR and varicella vaccines separately because studies show an increased risk of febrile seizures when they're combined. Talk to your child's doctor about getting the MMR vaccine instead of the MMRV vaccine if your child has ever had a seizure or if there's a family history of seizures.
What are the possible side effects?
Mild reactions are fairly common. Up to 1 in 5 children gets a low fever, and 1 in 20 develops a mild rash. In rare cases, a child has swelling in the glands of his neck or cheeks.
If these problems occur, they usually do so within five to 14 days of getting the shot. A child is more likely to have these symptoms after the first dose.
Moderate reactions are less common. About 1 child in 3,000 who gets the MMR vaccine has a seizure caused by high fever. With the MMRV vaccine, as many as 1 in 1,250 has a seizure.
Though these febrile seizures may seem scary, they're almost always harmless for the child.
Up to 1 person in 40,000 will have a temporarily low platelet count, which may cause bleeding problems.
Severe allergic reactions are rare but possible with any vaccine. See what our expert says about how to tell whether your child's having an adverse reaction.
If your child has an adverse reaction to this or any other vaccine, talk to your child's doctor and report it to the Vaccine Adverse Event Reporting System.
Is there a link between the MMR vaccine and autism?
In 1998, the British medical journal The Lancet published a study connecting the MMR vaccine and autism. Researchers noticed that eight of the 12 autistic children being studied had started showing symptoms of autism around the time they received their MMR shots, and the researchers hypothesized that the children were having a physical reaction to the vaccine.
It turned out to be a coincidence, and the study has now been repudiated by most of the researchers associated with it and retracted by The Lancet. An editorial published in the British Medical Journal in 2011 called The Lancet study "fraudulent" and noted that the lead author has been stripped of his academic and medical credentials.