By Jocelyn Schauer
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February 17, 2025
There is currently an outbreak of measles in mostly unvaccinated individuals in several states, including a large outbreak in western Texas. Unfortunately, the Centers for Disease Control (CDC) website is only being updated weekly at this point, so please check the national news or local health department websites for the latest information on case numbers for each state. The Healthy Children website has a comprehensive description of measles and the vaccine schedule for children here. Remember that the measles vaccine is extremely safe and protective. However, it is a live vaccine and so some who are immunocompromised or pregnant cannot get the shot (if they were not immunized previously). Also, the first dose is typically administered at 12 months of age, so most infants are at high risk for getting infected. Infants, other unvaccinated, and immunocompromised individuals all rely on herd immunity to keep them safe, so it is important to keep communities protected against measles to protect everyone. When herd immunity drops below 95%, outbreaks are likely to happen once someone with measles enters the community (often from international travel). Some measles facts: Measles is considered one of the most infectious diseases (airborne) on earth. If 10 unvaccinated people are exposed to someone with measles, 9 will get infected. It can also make children very sick - for people without immunity, 1 in 5 will be hospitalized, 1 in 20 will develop pneumonia (the most common way measles kills young children), 1 in 1000 will develop encephalitis (infection of the brain, sometimes causing permanent brain damage), and 1-3 in 1000 will die. It can cause “immune amnesia,” where the immune system loses its ability to fight other viruses that people were previously immune to. Children are normally vaccinated against measles with the Measles, Mumps, Rubella (MMR) vaccine at 12 months and again at 4-5 years of age, but can get an accelerated schedule in case of outbreaks. Accelerated schedule in case of community outbreaks: Extra dose for 6-11 month old infants, with second dose at 12+ months of age (28+ days after the first dose) For children who have only had the 12 month dose, they can get their second dose of vaccine 28+ days after the first dose. The vaccine is fully protective approximately 10-14 days after administration (93% protection after 1 dose, 97% protection after the second dose.) People born before 1957 might not require vaccination because measles was so widespread in the mid-1950s and earlier, it is assumed that everyone already had the disease and has natural immunity. However, during an outbreak it might be worth checking immunity (IgG to measles) or getting an MMR booster. People born between 1957 and 1968 may have gotten only 1 dose of killed measles vaccine (less effective than the current vaccine) and should check immunity (IgG to measles) or get an MMR booster if they have not previously gotten a second shot. Because MMR is a live attenuated virus vaccine, those who are pregnant or significantly immunocompromised cannot get the vaccine. Find more measles information at HealthyChildren.org . We will continue to update this site.