How likely is it that the MMR vaccine protects against COVID-19?
December 23, 2020 5:02 PM   Subscribe

Some recent studies have suggested that antibodies from the MMR vaccine may be protective against severe COVID-19 infection, see for example here for a correlative study. I would be interested in opinions from scientists more knowledgeable than I am about how legit this is likely to be.

Is this effect probably a coincidence or is there some solid reason why mumps antibodies could be protective against severe COVID-19? Is this result likely to be real enough that it could affect clinical practice? Is it worth it, for example, to talk to my doctor about possibly getting an MMR booster?
posted by medusa to Health & Fitness (9 answers total) 3 users marked this as a favorite
I have no medical opinion, but as someone who currently has Covid, and is the parent of a 22yo and an 18yo who have been almost as sick as I've been, and a grandparent of a 2yo that also had the same identifiable symptoms... I'm pretty darn skeptical. Every one of us is current on their MMR shots/boosters.

I'm also pretty darn skeptical of this "everybody young is asymptomatic" thing. Even the 2yo has been sick for a week and a half. We did have one - a 20yo - with no symptoms, but he's also the one that NEVER CATCHES ANYTHING. If such a high percentage of kids are being called asymptomatic, their parents aren't paying enough attention. It can be subtle, as many kid illnesses are, especially since the fever and other symptoms come and go, but it's definitely there.
posted by stormyteal at 5:40 PM on December 23, 2020 [4 favorites]

There were no significant correlations between mumps titers and severity in the comparison group, between mumps titers and age in the MMR II group, or between severity and measles or rubella titers in either group

Emphasis mine. I am a scientist with some training in modeling of infectious disease. I will also note the sample size of that study is 80 patients.. This is like studying the effects of a massive gulf coast hurricane based on 15 houses.

Color me skeptical. Conversely: if there was some notable effect, after millions of cases and millions of MMR vax recipients. We wouldn't be guessing right now, after a whole year of people striving for answers. We would probably know. Ymmv, etc.
posted by SaltySalticid at 6:17 PM on December 23, 2020 [10 favorites]

As a layperson, I think it's worth getting an MMR booster because it's important for adults to keep updated on these things, especially as things like mumps and measles make a comeback. Definitely do ask your doctor. Do you ever travel? I've gotten the MMR before international trips, though it's also spreading in my own community. Even Dr. Fauci is concerned.

I can't speak to the MMR and Covid, but there have been a few studies suggesting a correlation between the BCG vaccine for tuberculosis and lower incidence or severity of Covid, and other suggestions that maybe that's not true. But none of this is far enough long in research to suggest this is a way to prevent or minimize Covid.

But, yes, it's good to be updated on vaccines, for flu or measles, or whatever else is out there.
posted by bluedaisy at 6:51 PM on December 23, 2020 [1 favorite]

The simplest explanation for this result (and indeed any correlation between what seems like an unrelated preventative treatment and covid) is:

1. People who are able to take care of their health are on average richer. They are therefore less likely to catch covid in the first place because they are more likely have a job they can do from home and less likely to live in a high occupancy household.

2. People who are able to take care of their health are on average healthier (no kidding) and have access to better healthcare. They are therefore less likely to have severe cases of covid if they do get it.

In other words, in the absence of a much bigger study than N=80 (!) that is able to control for confounding variables such as demographics, this study shows that it's good to be rich.
posted by caek at 9:16 PM on December 23, 2020 [7 favorites]

Best answer: The paper is more than just the N=80 study. The second major portion of the study was analyzing all known COVID-19 cases in the U.S., ages 0-44, 1 Jan 2020 to 2 Sept 2020, broken down year by year.

The figure resulting from that analysis is really, really interesting. And it meshes rather exactly with the hypothesis they made in the first part of the study (people over a certain age didn't receive the innoculation that, they hypothesize, creates the positive results. And among those who DID receive the right innoculation, the antibodies from it start to wane by about age 14. And so...the results summarized in that figure match rather exactly what you would expect given that situation). So that is some really nice confirming evidence.

There is also a third important part, where they hypothesize a pretty precise mechanism that would cause all of this.

All in all, it seems to be a pretty cool paper and a great example of how science can and should proceed.

Given that, this is all still SUPER PRELIMINARY. They are in the stage of making and testing hypotheses here, and definitely not in the stage of having firm results and making firm recommendations.

Or in fact making ANY recommendations AT ALL to the public.

The study authors fully agree with this. In a Healthline article summarizing the research, two of the authors put it this way:
However, Goldenberg stopped short of recommending that adults start asking for booster MMR shots.

“Administering MMR vaccine to adults to decrease illness severity during a COVID infection should not be considered until randomized clinical trials demonstrate efficacy,” he told Healthline.

Gohil concurred.

“It’s important to be thoughtful about it. I don’t think you should be giving someone a booster just because there’s a potential link,” she said.

Gohil said there haven’t been studies on giving boosters to adults, and we don’t know what side effects there might be. More research would be required before making such a recommendation.
I'll confess reading this research made me think about getting and MMR booster. But that is about 95% because I got thinking about how long it's been since I had the MMR shot and how much my immunity must have waned by now. And--even more important--how many idiot anti-vax relatives I have.

We've literally had large contagious disease outbreaks at family gatherings because there are so many unvaccinated kids (and now, adults) around. And on top of that, immunity from immunizations does wane as the years go by. So one kid happens to have a measles case when they come to family reunion, pretty soon it's a measles fest thanks to the numerous unvaccinated kids around, and then some of the older adults (immunized 40-70 years ago) end up with a case, too.

For the kids the cases are invariably minor but the older adults typically have far more serious and long-lasting cases. This isn't hypothetical; my sister-in-law still suffers aftereffects from her lengthy bout of whooping cough about 15 years ago. chances of being exposed to measles, mumps, or rubella over the next say 15 years are actually rather high and the consequences not good at all. In that situation, I start to think that an MMR booster might make a lot of sense.

And the remaining 5%: maybe-maybe-maybe the MMR booster would help in case of exposure to Covid, too. But wouldn't even be going through my head at all right now if the Covid angle were the ONLY angle.
posted by flug at 12:32 AM on December 24, 2020 [8 favorites]

I'm a total lay person but I wonder if measles' ability to wipe out immune memory has anything to do with it? As in, if you get measles, your body is less protected from other things it's been exposed to (illness or vaccine) and you're more susceptible to future diseases. And someone without the booster is more likely to get measles if exposed.

This Podcast Will Kill You: Measles
Includes sources
posted by carrioncomfort at 4:57 AM on December 24, 2020

Best answer: As they point out, this wasn't a shot in the dark; there is structural similarity between the viruses that suggested it might help. The Gates Foundation actually funded a multinational randomized trial of an MMR booster to prevent severe covid (the trial is nominally a platform to study re-purposing multiple drugs, but I think the only one they are doing now is MMR). Disclosure: I know some of those investigators, and I participated in the trial. My reasoning was that even if the benefit was speculative, the potential risk was very low (and MMR titres start to wane with age anyway).
posted by a robot made out of meat at 6:20 AM on December 24, 2020 [2 favorites]

Here is some general info about who should get the MMR vaccine:
Who should get the MMR vaccine?

Children should get the first dose of MMR vaccine at 12-15 months of age, and the second dose at 4-6 years of age. Children can get the second dose at any age, as long as it is at least 28 days after the first dose.

Adults who have not been vaccinated nor had the diseases, or don't know if they've been vaccinated or had the diseases, and who meet any of the following criteria:

* Adults born after 1956
* Work in a medical facility
More info (from the University of Michigan, for incoming students), including why 1956 and 1971 are a key years:
If you were born after 1956, two doses of a combination measles-mumps-rubella vaccine (MMR) is recommended.

* Most people born in or before 1956 were infected with measles, mumps and rubella in childhood and are presumed to be immune.

* People born in the 1970's are less likely to have received two doses.

* MMR vaccine is a live, attenuated (weakened) vaccine. It was first licensed in the combined form in 1971 and contains the safest and most effective forms of each vaccine.

* The vaccine is 75-91% effective, even with two doses.
Also, interestingly, there was a version of the vaccine used on some patients 1963-67 that didn't work very well. So if you were immunized for measles during that period it might be a good idea to get re-immunized (again, for measles prevention purposes, nothing to do with Covid).
posted by flug at 9:33 AM on December 24, 2020 [1 favorite]

Best answer: Please don't read too much into these after-the-fact investigative studies that show possible correlation. Please trust that research immunologists and the entire scientific community would have encouraged you and everyone else on this planet to get an MMR booster if there were any evidence at all that this could be even a teeny tiny bit worthwhile.

It's a non-story, there is no clinical practice application. This is of interest to research scientists and surely will be for years but don't put your eggs into the same basket that just dumped out hydroxychloroquine.
posted by juniperesque at 10:45 AM on December 24, 2020 [2 favorites]

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