A thousand people with chickenpox
April 10, 2016 11:32 PM   Subscribe

I had chickenpox as a child, and so I'm immune. But what if I sat in a crowded room with a thousand people with chickenpox - could I get it again? Would the chance be higher?
posted by gorcha to Health & Fitness (16 answers total) 1 user marked this as a favorite
It would be very very unlikely for you to contract chicken pox again, but it might be possible. This is the NHS advice:
How might someone get chickenpox again?
There are several theories that could explain how someone might get chickenpox more than once. For example:

Many medical professionals believe that the person’s condition was misdiagnosed first time around, and that they had another condition with similar symptoms.

There may be a genetic link. In the US studies mentioned above, around half of the people who reported having chickenpox before said that other members of their family had also had chickenpox more than once.

There may be more than one strain of the chickenpox virus. If this is the case, it may be possible for someone to be infected by a different strain each time. However, there is no scientific evidence to support this theory.
posted by Catseye at 12:17 AM on April 11, 2016 [1 favorite]

It's possible for chickenpox to recur, but not specifically because you were exposed to a thousand people with chickenpox. Chickenpox is very contagious and it only takes inhaling a few particles of it to contract it, but once you have it, the varicella virus generally stays dormant in your body for the rest of your life. - so if you had the illness again, it would be more a problem with your immune system allowing the virus that's already in your body to reactivate than "catching it" again.
posted by treehorn+bunny at 12:44 AM on April 11, 2016 [2 favorites]

I know treehorn+bunny is a doctor, so I'm sure she's right that usually it would be due to reactivation of the virus, but I can tell you that I had chickenpox the first time as a child of about 4, and then caught it again when it was going through our school when I was 13. (I know it was a matter of it going around, because I was in a school theatre production that month, and about 10 of us were out with chickenpox, leaving a lot of very happy understudies.)

Of course, it's possible that it was misdiagnosed when I was four and wasn't actually chickenpox, but that's what my mother said the doctor diagnosed it as. And it was definitely chickenpox the second time around (although mine was fairly mild and the doctor that time said it might be milder because I had already had it.)
posted by lollusc at 1:03 AM on April 11, 2016

I think it would actually REDUCE your chance of getting shingles; now that immune adults are no longer routinely exposed to children with chicken pox (because kids get vaccinated), the incidence of shingles in adults has risen. Periodic exposure to the virus appears to help keep it suppressed, preventing an outbreak of shingles in the exposed individual. Pediatricians are substantially less likely to develop shingles than their peers, as they are still fairly routinely exposed to chicken pox in patients.

It appears as an interesting case in the medical ethics literature: by vaccinating for this common childhood disease we'll be increasing the incidence of a related disease in older adults because they won't have access to suppressive exposure if kids aren't sick. (The answer, eventually, is shingles boosters for adults. But you can see why it's an interesting ethics question to play with.)
posted by Eyebrows McGee at 3:28 AM on April 11, 2016 [2 favorites]

Data point, I had chicken pox twice, at three and seventeen. No idea how it happened, but it did, and it was unfortunate.
posted by roomthreeseventeen at 5:55 AM on April 11, 2016

I had chicken pox twice as a child, and my brother had it three times. All mild cases. I have had shingles as an adult (in a toxic stress situation). Most people have a lifelong immunity, but a few are just susceptible, I guess.
posted by Malla at 6:00 AM on April 11, 2016

So it's not the case that if I was to somehow suddenly expose myself to chickenpox at hundreds of times the level of a single case of chickenpox, that my immune system would be unable to cope or react fast enough?
posted by gorcha at 6:16 AM on April 11, 2016

Just to add to the anecdata, I, too, have had chicken pox twice—and bad cases both times. Once when I was 3 and once when I was 12. It was memorably awful both times.
posted by mothershock at 8:48 AM on April 11, 2016

I'm another who's had it twice. Age three the first time and somewhere around 11 or 12 the second time. I read somewhere that being very young when you first have it makes you more susceptible to getting it a second time, but of course I can't find a cite for that right now.
posted by MsMolly at 11:10 AM on April 11, 2016

Another twice bitten here. I have always so wondered if that means I am more likely to bet shingles.
posted by futz at 12:00 PM on April 11, 2016

"So it's not the case that if I was to somehow suddenly expose myself to chickenpox at hundreds of times the level of a single case of chickenpox, that my immune system would be unable to cope or react fast enough?"

No. If that's how the immune system worked, even immune doctors could not work in infectious disease wards. Or parents of large families whose kids all caught chicken pox at once would have been more likely to re-catch chicken pox themselves. They did not.
posted by Eyebrows McGee at 12:53 PM on April 11, 2016

My understanding is that if you have had chickenpox you still have chickenpox - the virus lies dormant in your nerve sheaves but never goes away. If it becomes active again later in live, you get shingles. So your immune system is constantly dealing with the chickenpox virus throughout your life.

Its a different story if you are vaccinated against chickenpox. The vaccine is about 98% effective, definitely good enough for public health herd immunity purposes , but not a sure thing for an individual. The Mumps vaccine is worse, about 88% effective, and a friend who had the vaccine caught the Mumps after working with several people who already had them.
posted by rtimmel at 1:49 PM on April 11, 2016

I've been vaccinated twice and still don't have immunity, per blood test. Not sure if that is a good thing or a bad thing...
posted by SakuraK at 8:13 PM on April 11, 2016

Sounds like a great premise for a social science fiction type novel / movie!

Sure, there are plenty of us who have had chickenpox twice / had chickenpox and then got shingles / had the vaccination and still contracted chickenpox. But that's not what you're asking...

You want to know whether there is a threshhold level beyond which any natural immunity (from vaccination or from having chickenpox the first time around) becomes irrelevant, and is effectively overrun by the sheer volume of virus?

(I don't know the answer, I'm just trying to reframe the question on your behalf. Please shut me down if I'm completely off track...)
posted by finding.perdita at 12:54 AM on April 12, 2016

More anecdotal fuel for the fire. I have had chicken pox twice. Both light cases. I've had shingles twice as well. Once was pretty uncomfortable but the second time was so light I didn't realize what it was until one of my coworkers who had never had chicken pox before, came down with it. He had no other exposure that he knew of so it seemed he got it from me. I felt terrible because his case was quite serious.
posted by WalkerWestridge at 12:48 PM on April 12, 2016

@finding.perdita yes that's it.
posted by gorcha at 5:16 AM on April 13, 2016

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