The MMR vaccine is a combination vaccine, immunizing against more than one disease in the same injection (therefore reducing the number if injections needed), though we don’t tend to think of it as a combination vaccine because it has been given this way for so long (since 1971). The MMR vaccine stands for and protects against three diseases: Measles, Mumps, and Rubella (German measles). These three vaccines used to be available separately; however, they are no longer available.
Diseases
Measles is a common childhood viral illness; before the vaccine, virtually all children would catch it by the time they were 15 years old. It causes fever, runny nose, cough, and a characteristic rash. Children with measles also commonly develop ear infections or pneumonia. It can cause brain inflammation (encephalitis), and about 1-2 out of every 1,000 children infected dies from measles. Measles can also cause miscarriage or premature birth in pregnant women. It is still common around the world, killing about 500,000 people every year. Outbreaks are still occurring in Europe and the United States, particularly in unimmunized populations. The virus is extremely contagious and is spread easily and quickly from child to child through breathing, coughing, or sneezing.
Mumps is a viral infection that causes a well-known swelling of the salivary glands in the cheeks. It also causes fever, headache, and can cause sterility if a male gets it after puberty. It can cause meningitis, encephalitis, deafness, and can be fatal in some cases. It is spread easily from person to person through the air. It was very common in children before the vaccine but is uncommon now. However, outbreaks still occur in the United States, and it is still seen overseas.
Rubella, also known as German Measles or 3-day measles, used to be a common childhood disease. The disease is usually mild and causes fever, rash, swollen glands and sometimes painful joints. It spreads easily from person to person. While the disease is mild in children and adults, it can be deadly to unborn babies. It commonly causes miscarriages, deafness or blindness if a woman gets rubella while pregnant. During the last epidemic in the 1964-1965, 20,000 babies were born with congenital rubella syndrome. The vaccine became available in the late 1960’s and the disease has almost disappeared, though it is still important to be sure pregnant women are immune to rubella.
The Vaccine
The MMR vaccine has been available in its combined form since 1971; the individual components were developed in the 1960’s. It is a live virus vaccine, meaning each of the three viruses are alive but weakened so that they cannot cause disease. The MMR vaccine is given at 12-15 months of age. A booster dose is given at 4-6 years of age.
The MMR vaccine is also available as a combination vaccine with varicella (chickenpox) vaccine as the MMRV vaccine.
Side effects
About 20% of children can get fever and/or a rash about 1-2 weeks after the shot; it does not usually cause any side effects right after it is given. It can occasionally cause swollen lymph nodes or mild joint swelling, both of which go away. There have been reports of febrile seizures in some children when they get a fever from the vaccine, but this is caused by the fever, not the vaccine. There have been reports, extremely rarely (1 in a million doses), of children developing encephalitis (inflammation of the brain); however, it is unclear if the vaccine is really the cause or if it is just coincidence. On the other hand, if 1 million children caught measles, over 1,000 of them would develop encephalitis.
In the 1990’s, it was suggested that MMR vaccine, especially the measles component, might be linked to autism. Autism symptoms typically appear from 15-24 months of age, after children receive the vaccine, so the two can appear to be related. A lab reported measles genetic code in children with autism. The link between autism and the vaccine has been studied extensively over the past 20 years, probably more than any other vaccine has been, and there is no evidence at all to suggest any link between autism and MMR vaccine. Furthermore, in 2006 the initial lab studies were proven to be a mistake, so there is now not any objective, scientific evidence at all to suggest any link between autism and MMR vaccine.
Risks vs. benefits
The risks of the vaccine are small, with the side effects noted above, and though there has been a lot of questions about this vaccine, it has been extensively studied and there do not seem to be any serious side effects. Measles and mumps outbreaks continue in this country and around the world, with serious and deadly outcomes. It appears that the benefits of the vaccine outweigh the risks. I do vaccinate my children with this vaccine.
Contraindications & Precautions
Children who have had a severe allergic reaction to gelatin or to the antibiotic neomycin should not receive the vaccine. Children with suppressed immune systems due to HIV, cancer, or steroid use should discuss the vaccine with their doctor. Children who have received blood transfusions or other blood products may have to wait several months before receiving live virus vaccines. If a child has received a live virus vaccine like varicella recently, the MMR vaccine should not be given until 4 weeks after the other vaccine. They may, however, be given the same day.
Resources
MMR (Measles-Mumps-Rubella) Vaccine Information Statement from the CDC
Published June 13, 2005. Last updated November 5, 2016
