I understand vaccines can wear off in some adults. How do I tell if I need a booster shot for measles?
In general, many vaccines require booster doses to confer ongoing immunity. For example, we update tetanus every 10 years. On the other hand, some vaccines confer ongoing immunity if the series is completed.
In the case of the measles vaccine, it was introduced many years ago and only one vaccine was given. It subsequently had been found that one vaccine does not give sustained immunity to everyone. If you only had one shot, as most did between 1970 and the early 1990s, as many as 15 percent may not have sustained immunity. If you have two shots, as became routine practice in the mid 1990s, the immunity increases to as high as 99.7 percent.
When we first introduced the chicken pox vaccine, it too was given as a single shot. With ongoing study it was found a second dose of the vaccine would boost the immunity and offer continuing protection. Typically measles is offered after the first birthday and chicken pox a few months later. At age four, the newer combined vaccine for measles, mumps, rubella and chicken pox is given again. People born before 1970 are thought to be immune to the disease through exposure.
Measles is a highly contagious disease that is spread from body secretions. When you cough or sneeze, the virus particles are propelled into the air and can stay suspended indoors for up to two hours. Individuals with measles are infectious and contagious days before the rash appears until four days after the rash appears. It presents with high fever, a runny nose, cough, watery eyes (conjunctivitis), white spots in the mouth called Koplik spots and of course the rash itself.
Measles caused 145,000 deaths throughout the world in 2013. One in 3,000 are at risk of dying and there are other serious complications such as encephalitis, pneumonia, otitis media and diarrhea.
The best strategy to protect you and your family is to make sure your immunizations are up to date. Keep a record of your vaccinations and review with your health care provider what vaccines need to be updated.
Originally published in ParentsCanada magazine, April 2015.