In the decade before 1963, measles infected 3 to 4 million people in the United States each year, according to the Centers for Disease Control and Prevention (CDC). What’s more, each year the respiratory illness killed 400 to 500 people, hospitalized 48,000 people, and caused encephalitis (severe brain inflammation) in 4,000 people in the United States, as well as other serious symptoms of measles. The measles vaccine, developed in 1963, greatly reduced infection rates. Between 2000 and 2013, there were only 37 to 220 cases of measles reported in the United States each year, and most of these infections originated outside the country, according to the CDC. The vaccine also reduced infection and death rates in other countries, though measles is still one of the leading causes of worldwide childhood death, according to the World Health Organization (WHO). Still, the vaccine prevented an estimated 15.6 million deaths between 2000 and 2013, according to WHO.
What Is the Measles Vaccine?
The measles vaccine contains live, weakened (attenuated) strains of the measles virus, which replicates in people just like the normal measles virus. It works, essentially, by priming your immune system. When your immune system encounters the weakened virus in the vaccine, it produces antibodies against it. The same antibodies also protect you against the full-strength measles virus if you become infected in the future. In 1971, the measles vaccine was combined with the vaccines for mumps and rubella to form the measles-mumps-rubella (MMR) vaccine. In 2005, the MMR vaccine was combined with the varicella (chickenpox) vaccine to form the MMRV vaccine. Individual vaccines for these diseases are no longer available in the United States. The MMR vaccine typically comes in two shots, which are administered subcutaneously, or into the fatty layer of tissue beneath the skin. The first dose produces immunity to the measles and rubella in up to 95 percent of people (the vaccine is less effective for mumps), according to the Immunization Action Coalition. The second dose helps to produce immunity to the diseases in people that didn’t respond adequately to the first dose, and to give a “booster” effect to those who did develop an immune response. But even after the second dose, some people still do not develop immunity.
Who Should Get the Vaccine?
The CDC recommends that all children get the MMR vaccine. The first dose should be given between 12 and 15 months of age. The CDC recommends that the second shot be given between 4 and 6 years of age, though it can be given at any time as long as it’s 28 days after the first dose. As an adult, you may not need to get the MMR vaccine if you:
Were vaccinated as a child, with either two doses of MMR, or one dose of MMR and a second dose of an individual measles vaccineWere born before 1957 (you likely had the diseases as a child and are now immune)Are immune to measles, mumps, and rubella, according to blood testsAre female and born before 1957, and are sure you will not be having any more children, already had an individual rubella vaccine, or had a positive rubella test
If you’ve only had one MMR dose and are at a low risk of coming into contact with the viruses, you may not need a second dose. However, you should make sure to get two doses of the MMR vaccine if you are:
Someone who received the inactivated (killed) measles vaccine, which was used from 1963 to 1967Someone who received the inactivated mumps vaccine before 1979 and are at a high risk of infectionA female of childbearing ageA post-high school studentPlanning to travel internationally or on a cruise shipA healthcare worker in a hospital or other medical facilityLiving in area with a current outbreak
You should not get the MMR vaccine if you are already pregnant, have had an allergic reaction to the first dose, or have a severally compromised immune system from HIV/AIDS, leukemia, or other health issues and treatments.
Side Effects of the Vaccine
There is no evidence that the MMR or MMRV vaccines cause autism. Reported side effects of the MMR vaccine may include:
FeverMild rashJoint painTemporary low blood platelet countSwelling of the glands in the cheek, neck, or under the jawSeizure caused by high fever
Other, rare side effects of the MMR and MMRV vaccines have been reported, including:
Permanent loss of hearingLong-term seizures, coma, or lowered consciousnessBrain damage
However, these side effects are so rare that scientists aren’t sure if they’re actually caused by the vaccines.
