The measles, mumps, and rubella vaccine (MMR) is routinely given between the ages of 12-15 months of age, although we’ll give it to infants as young as six months who are traveling to measles-endemic areas of the world. (The reason why we wait until after the first birthday is that an infant will have received immunity from maternal antibodies, but only if his or her mother has been appropriately immunized through natural infection or vaccination.) The second MMR is given at the kindergarten age of 4-6 years. (The reason why two MMR’s are given is because just a single MMR gives full protection to 90-95% of recipients, whereas the second dose gives fully 99% of recipients full protection against measles, exceeding the threshold needed for true herd immunity.) Two MMR vaccines are required to enter public (and most private) kindergarten programs unless there is a medical exemption (which is, thankfully, very rare), or personal/philosophical objections which are still allowable in some states. Currently, many state governments, as well as the U.S. Congress, are considering new legislation to eliminate these discredited excuses.
The CDC’s recommendations for adult MMR vaccinations are clear:
- Adults born before 1957 most likely had measles and mumps during childhood (remember, these viruses are probably the most contagious pathogens known) and, therefore, don’t need MMR vaccine.
- Adults born in 1957 or after should have either documentation at least one dose of MMR or documented immunity (a blood test measuring antibody titers) to measles or mumps. Adults who are students in a postsecondary educational institution (college and graduate school), work in a health care facility, or
plan to travel internationally need to have documentation of two doses of MMR.
- Adults who received a dose of inactivated (killed) measles-only vaccine between 1963-1967 should be revaccinated with 2 doses of MMR vaccine (each dose separated by 28 days) to protect against measles; those who received a dose of killed mumps-only vaccine before 1979 should consider the same two doses of MMR vaccine to protect against mumps, especially if they work in a high risk environment, like health care.
Children and teenagers who have never been vaccinated with the MMR vaccine — either because they had a prior-but-now-resolved medical contraindication or because their parents decided not to administer the vaccine — should receive two doses or MMR, each dose separated by 28 days, in order to protect themselves, and the ones they come in contact with, from measles, mumps, and rubella.
Both measles and mumps have been in the news lately, but the other important virus we shouldn’t overlook is the “R” in the MMR. We’ll look at rubella tomorrow.