Measles may be the most contagious viral disease on earth. If an unvaccinated person is exposed to the measles, there is a 90% chance that they’ll come down with it, and they can be exposed two hours after the person with measles has left the room. By contrast, think about all the times you’ve been in the presence of a coughing, sneezing, miserable person and not caught their cold: unless you live in a bubble (or an isolated community that has no children in it) you’ve been sneezed on far more times than you’ve ever gotten sick.
I was born in 1973 and had the MMR as a toddler, like nearly everyone back in the pre-vaccine-freakout era. In the late 1980s, when I was in early high school, I got taken in for a second MMR. I remember the nurse giving me the shot saying, “there. Now you’re set for life!” “Wasn’t that what you said the first time you gave me one of these?” I asked.
I was under the impression that the shot I’d gotten as a teenager was a booster, but technically, it wasn’t; it was just a second shot. Here’s the thing. Out of 100 toddlers who receive the MMR, 95 will develop complete immunity. The remaining 5 experience “primary vaccine failure,” which means that for whatever reason, their immune system did not respond to the vaccine and didn’t make antibodies to it. The second shot isn’t to boost immunity — with a tiny handful of exceptions, the immunity from the MMR is lifelong. The second shot is just insurance, to cover the 5% who didn’t get the immunity from the first shot.
Nearly everyone who didn’t respond to the first shot does respond to the second shot. There was about 20-year period, though, when they thought one shot was plenty. They changed their mind on this in the late 1980s, and told everyone to come back in and get a second shot, just to be sure, and that’s when I had my smart-alecky conversation with the pediatric nurse.
So let’s say you’re in your 40s or 50s. Think back. You may remember going in for that second MMR, like I do. If you don’t, you might just not remember it, or it’s possible your parents were flakes, or — depending on how old you were in the late 1980s — it’s also possible you just missed the memo and didn’t get it done (because God knows plenty of us were uninsured or just sloppy about preventive care in our early 20s.)
Even if you never had that second shot, you’ve got a 95% chance of being fine. But if you’ve been feeling uneasy about the measles since hearing about the latest outbreak, and you don’t remember a shot in your teens, talk to your doctor: they can do a blood draw to check your immunity level. (Or, they can just give you another MMR, since it’s a needle poke either way and there’s no particular risk to a third MMR.)
As it happens, if you’re my age, you’re quite a bit more likely to be vulnerable to the chicken pox. Most of us had it — but a few didn’t. If you don’t remember getting it, don’t assume that you had it when you were too young to remember, unless your parents back that up. If your parents say something like, “oh, surely you had it. Your siblings all had it. We figured you just had a very mild case” — you probably didn’t have it and that means you could catch it tomorrow.
Varicella is a much less serious disease than the measles but is solidly in the “no fun: not recommended” category, and — like the measles — there’s a vaccine. You can go to the doctor and tell them that you do not recall having had the chicken pox, and they will give you the vaccine that day and not only will you never catch the chicken pox, you’ll never get shingles.
Anyway. A small number of people do lose their immunity to measles over time; if you’re very worried, you can have yourself tested, although for the most part the people who lose immunity are in the category of “this is why herd immunity is so important” — it’s a sufficiently rare occurrence that it doesn’t make sense to test and re-vaccinate everyone.
You can also wind up susceptible to measles if your immune system is suppressed (say, because you’re being given chemotherapy for cancer) and if you ever have a bone marrow transplant — FYI, those are rumored to be even less fun than measles but if you’re having one, it’s probably because you really need it — you’ll have to be re-vaccinated against everything that you can be re-vaccinated against.
One final note, since not everyone knows this: if you are too young or your immune system is too compromised for a regular vaccination, and you get exposed to the measles, there’s also the option of an immunoglobulin shot, where they essentially shoot you up with the antibodies to fight off the infection you’ve been exposed to. Getting the immunoglobulin is much less fun than a regular vaccination — think much larger needles, and a whole lot more of them — but still beats the hell out of measles.
The bottom line, though: if you were vaccinated, you’re very unlikely to get the measles, even if you fly across the country with a measles patient in the next seat. Isn’t that nice? Vaccination is awesome.
[Illustration via Shutterstock]