BY KEITH ROACH, M.D.

Not all people born before 1957 have measles protection DEAR DR. ROACH: My husband and I read your column regularly and appreciate your attention to science and facts, especially when addressing issues related to infectious diseases and vaccines. I am writing today because I am deeply unhappy about the repeated messages in the press to those born before 1957 — or sometimes 1955 –who, as you wrote, “can be safely assumed to have lifelong immunity to measles due to having had this extremely contagious disease.”

Having been born in 1953, I was similarly advised about this by my internist. I questioned this advice, and my doctor said he’d happily test me but that everyone he’s tested to date in this age cohort showed immunity. I asked for the test, and my test came back stating that I was “not consistent with immunity.” I immediately went to get vaccinated. My husband didn’t bother to get tested and went to get the vaccine as well.

I have no idea whether I received an MMR vaccine as a child. Whether I did or was exposed to the virus itself is irrelevant for me and anyone else in this age group. Protection is as simple as getting a flu shot to be inoculated against measles.

Please advise those born before 1957 to get tested to determine their immune status or just go and get what seems to be a harmless vaccine that is available everywhere, for the peace of mind of knowing that they have protection. There’s no sign yet that the measles spread is slowing. It’s not clear from the news how many adults have been afflicted. — M.E.

ANSWER: According to numerous well-done studies, the risk for a person born before 1957 of getting measles is very low, but it isn’t zero. In a 2014 outbreak among the Amish, there were zero cases of measles among those born before 1957 in an outbreak of 383 people. However, in a 2018-2019 outbreak in New York City in an undervaccinated community, 5 out of the 649 cases of measles were among people born before 1957. It was not reported how many of these adults had an immune system disease.

About 95% of people born before 1957 will have protective antibody titers. Even among those who do not have protective titers, the risk of measles is still low since a previous infection leads to memory cells. These cells are still capable of building up large amounts of protective antibody titers quickly. In addition, some of the immunity to measles comes from T-cells, not antibodies, and neither T-cell immunity nor memory cells show up in an antibody titer.

Nevertheless, it is possible for people who were born before 1957 to get measles, and when they do, it is very dangerous. Three out of the five people who had measles in the New York outbreak and were born before 1957 needed to be hospitalized.

In summary, being born before 1957 is adequate protection when the country has a high-enough rate of immunity to protect the community, but the current outbreak shows that this is no longer the case in many communities. For people who are in an area with an active outbreak, it is reasonable to get their titers checked, even if they’re born before 1957, and get the vaccine if their titers are negative.