Metro Detroit measles outbreak: Vaccinated before 1989? You may need a booster

41 cases of measles confirmed in Metro Detroit

DETROIT - The number of confirmed cases of measles in Metro Detroit is still 41, but the number is expected to increase as more cases are confirmed.

Local 4's Dr. Frank McGeorge is closely following developments to answer the most common questions.

The number of possible exposure locations and steadily increasing case counts has people concerned.

Many people want to know whether they are already protected because of their age or documented history of vaccinations.

People born before 1957 are considered immune because the large majority of people older than 62 were infected with measles as a child and have lifelong immunity.

Anyone older than 62 who is concerned about measles can have their measles immunity level checked by a blood test or can get the MMR vaccine.

The next age group of special note is people born between 1957 and 1989. The first measles vaccine was introduced in 1963, but generally, only one dose was administered.

People between 30 and 61 years old who only received one dose of vaccine are considered to be immunized, but with only one dose there's about a 7 percent chance someone is not protected. Anyone in this group who might have been exposed or is concerned about measles should get a second MMR vaccine.

The second measles vaccine is often incorrectly called a "booster," but that's not accurate. One dose of measles vaccine induces a response 94 percent of the time. The second dose produces protection 97 percent of the time.

The second dose is essentially to catch the people who didn't respond the first time.

After 1989, two doses of the vaccine became routine practice. As long as people under 30 years old are vaccinated, they are considered protected.

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