Late-to-detect vaccine side effects
December 19, 2020 5:24 AM   Subscribe

I am pro-vaccine and will get the COVID-19 vaccine when it's available to me. I also want to encourage my vaccine-hesitant friends to do so as well. One thing that concerns some of them is fear of long-term side effects that we haven't had time to see yet from the vaccine trials. Has that ever been an issue with other vaccinations?

As far as I know, side effects from other vaccines have consistently appeared near the time of vaccination; there is no evidence of undetected problems arising more than a couple months later that could logically be attributed to a vaccine. But I don't want to try to persuade people with that logic if it's not true.

(I am aware that rare side effects may be seen as more people are vaccinated but I see that as a separate issue; for this question I'm only curious about late-to-detect side effects.)
posted by metasarah to Health & Fitness (24 answers total) 14 users marked this as a favorite
 
As far as I can recall, the only claimed "long-term side effects" of any vaccines have been medically established to be mythological, not real. Clinical trials tend to focus on short-term reactions and side-effects, as well as on efficacy.

And from a public health perspective, the immediate benefit to all people who receive a vaccine, and to the population as a whole, would far outweigh the detriment to the very small number of people who would experience it. For that small population, we have the Federal vaccine compensation system.
posted by megatherium at 6:19 AM on December 19, 2020 [1 favorite]


Best answer: Honestly yes, but I got vaccinated anyway. Pandemrix (H1N1 flu vaccine) caused narcolepsy up to a year after administration. That’s the only one I know off the top of my head, though.
posted by Missense Mutation at 6:38 AM on December 19, 2020 [3 favorites]


Response by poster: Clarification that I'm well aware that the negative effects of getting COVID-19 are far worse than those from a vaccine, but I try to approach persuasion from every possible angle.
posted by metasarah at 7:07 AM on December 19, 2020 [2 favorites]


The 1976 swine flu vaccine is believed to have cause Guillaine-Barre syndrome in approximately 460 people. Article here. That’s pretty well known in the anti-vax community.
posted by FencingGal at 7:26 AM on December 19, 2020 [2 favorites]


The oral, but not injected, polio vaccine can cause polio in unvaccinated people via a process that takes at least a year:
A potential, adverse effect of the OPV is its known ability to recombine to a form that causes neurological infection and paralysis.[22] This genetic reversal of the pathogen to a virulent form takes a considerable time (at least 12 months) and does not affect the person who was originally vaccinated. The vaccine-derived attenuated virus is normally excreted from vaccinated people for a limited period. Thus, in areas with poor sanitation and low vaccination coverage, the spontaneous reversal of the vaccine-derived virus to a virulent form and its spreading in the environment can lead to unvaccinated people becoming infected.
posted by Mitheral at 7:44 AM on December 19, 2020 [3 favorites]


The first rotavirus vaccine (RotaShield) was taken off the market after about a year due to the vaccine increasing the risk of intussusception - bowel obstruction - in infants.
posted by saeculorum at 7:55 AM on December 19, 2020


That OPV one is, of course, a PSA for why vaccination needs to be broad-based; only unvaccinated people got polio via the excreta.
posted by chavenet at 8:32 AM on December 19, 2020 [5 favorites]


I think a significant thing to note here is that the Covid vaccine, unlike every other vaccine in history, uses mRNA instead of a weakened disease agent to train the immune system to produce antibodies. The situation with the polio vaccine cant happen, since there is no actual virus in the vaccine. There is no clear 'apples to apples' here, since this is the first mRNA vaccine to be approved.

However! Since the RNA dissolves after it makes the protein spike, and the spike dissolves after connecting with the immune response cells, there's nothing left in your system after a couple weeks except the antibodies.

One thing to keep in mind, though, if you are in the US, is that the vaccine is unlikely to be available to any of you for many, many months. By that time there will be a fairly sizable number of people from both the clinical trials as well as the first groups getting vaccinated now who will have had plenty of time to develop side effects (if any, which I doubt). So perhaps you might wait until then, since the most important data (does THIS vaccine have side effects that occur later) will actually be available to you.
posted by ananci at 8:33 AM on December 19, 2020 [39 favorites]


Best answer: Also worth noting Guillian-Barré would probably show up within the first six weeks or so. It probably wasn’t detected in the trial because it was too rare to detect a significant increase, not because it showed up too late. (GBS also famously happens in response to infectious disease, even as relatively benign as food poisoning.)

And the narcolepsy side effect is also seen in people who actually contract H1N1. The thought is that one of the viral proteins mimics a signaling molecule (orexin) that controls, among other things, sleep. So either vaccination or illness can lead to autoantibodies in rare cases that could cause narcolepsy. But it’s a literal “one in a million” side effect from the vaccine. For something like this to happen with the current vaccines, there would have to be some undiscovered molecular mimicry between the spike protein (since that’s the only coding sequence used) and a human protein or peptide, plus probably some genetic susceptibility to autoimmune disease. If the H1N1 story is any guide it would still be extremely rare, and moreover could still happen if you didn’t get vaccinated (because the virus itself can cause it).
posted by en forme de poire at 8:54 AM on December 19, 2020 [12 favorites]


Clarification that I'm well aware that the negative effects of getting COVID-19 are far worse than those from a vaccine ...

Not necessarily? GBS is pretty terrible; it can last for years and is potentially fatal.

Just in the interest of covering all angles, you should realize that the statement I quoted above is not strictly true.
posted by mr_roboto at 10:22 AM on December 19, 2020 [3 favorites]


GBS can also occur after COVID-19, though, so you would have to show that the risk was actually greater from being vaccinated. The opposite is actually true for influenza: the vaccine is less risky than infection.

Note that also a recent study found that in general, unlike influenza or Zika, COVID-19 does not appear to be a particularly high risk factor for GBS, so it would be pretty unusual if for some reason the vaccine was.
posted by en forme de poire at 10:50 AM on December 19, 2020 [3 favorites]


Risk of GBS is about four times higher after influenza infection than after influenza vaccination.

A study in Norway during the 2009 pandemic (H1N1) influenza showed a much higher GBS in influenza patients with a relative risk of 4.89 (95% CI: 1.7–20.36). The risk of incidence of GBS post influenza infection was also higher than the relative risk of 1.1 (95% CI: 0.51–2.43) reported for pH1N1 vaccination.[58] (The relative risk for the infamous 1976 vaccine was 1.4, so higher than modern vaccines but still far lower than actual flu.)

Note that the mRNA mechanisms for Pfizer and Moderna's covid vaccines don't even use typical antigens, so the risk of a molecular mimicry mishap (basically what GBS entails) is extremely low.
posted by basalganglia at 10:54 AM on December 19, 2020 [2 favorites]


(Right, although you are still causing your cells to express the spike protein so there would theoretically be that possibility if that protein resembled something human? But I think one of these links points out that based on computational analyses people have done, there’s nothing obvious there.)
posted by en forme de poire at 11:16 AM on December 19, 2020


Read up on the use of mRNA therapies for cancer. The Covid-19 vaccine is closely related to when the same tech is used to personalize cancer treatments. There is data out there. The tech is not brand new.

This is a quote from a site giving information about mRNA treatments for cancer patients: "mRNA is made up of four nucleic acids, abbreviated as the letters A, U, C and G. The order in which these are arranged is read by the cells like the ingredients in a recipe for making proteins. If the mRNA recipe cannot be read, it will have no effect and therefore also no side effects. However, if the opposite happens, the body will make only exactly the protein it needs—at the right time and in the right place."

Animal studies have been done as a precursor for using the therapy on humans.
posted by Jane the Brown at 11:58 AM on December 19, 2020 [1 favorite]


Something I would recommend on a personal level is asking them where they think the risk of vaccination falls in comparison to driving a car (or riding in, or walking near), chronic stress, accidental head/spine/joint injuries sufficient to alter lifestyle (doesn't take much), pregnancy/childbirth if they have done so/plan to do so/have or will cause it to happen, or family history of heart/diabetes/cancer.

I think the lack of control really drives a lot of these fears. All the rest feel like decisions (having blown my knee out this summer, I assure you that's an illusion; if you've ever had a car accident, you know how much of that is just physics) people are getting to make, and this doesn't. We like to pretend we're going to get to live lives entirely free of Bad Things because we choose to, and then something like this comes along and the potential bad outcome looms so much more large than the little choices we make every day. (And then some of us are still so certain Bad Things can't happen to us that we refuse to wear masks and demand the right to get our food spit on.)

The truth is that getting to and from the vaccination visits are way more dangerous, unless someone comes to your house to do it, and then it's falling in the shower beforehand that's more dangerous.

It's also entirely possible that the vaccinations we've all had over the years are actually having some kind of long-term effect on some or all people, and it's simply so diluted by additional factors and sheer numbers that we don't know, and it's such a slight difference from previous unvaccinated generations (or skewed because they had far worse fetal and developmental nutrition/food safety, higher childhood stress, etc) that it does not stand out as statistically significant. So we're all getting the bad thing, and nobody even knows it.

(We could all be getting a Good Thing we don't even know about, too. Our immune systems may in general be better at certain things than they used to, or really specific things that if you look at the numbers you might be like "oh, clean water" or "hand washing!" but maybe it's inside us too. Almost impossible to know in many cases, at least with the science at hand.)

I just think we need to address the very human instinctive fears here, in part because voicing them in a way that gets listened to with empathy is really powerful and also a critical part of decision-making processes for a lot of people. Saying it out loud helps. Replying to them with a combination of a few useful facts and some encouragement to talk it all the way through helps.
posted by Lyn Never at 12:16 PM on December 19, 2020 [9 favorites]


mRNA is still experimental in oncology--no approved drugs, and most entrants in early clinical trials. (See here for example; a DrugBank search also finds nothing approved except the vaccines under discussion. There's not the long term, large number of patient data to detect rare side effects.

I don't think there's any known reason to worry about mRNA therapies in this case--I certainly don't--but it is new technology (and I did have at least one spirited conversation with a colleague, a pro-vax scientist, who was hoping for a more traditional vaccine by the time his number came up.)
posted by mark k at 12:20 PM on December 19, 2020 [2 favorites]


Re: anaphylaxis following the mRNA vaccine from Pfizer - has it been determined what prompts this response? I plan to get the vaccine, but have concerns because I had anaphylaxis after a dose of oral moxifloxacin (Avelox), an antibiotic, and it was a very scary experience. No problems with any other vaccines, though I do have other med allergies (rash, no anaphylaxis, fortunately). I will, of course, discuss this with my doctor, but I'm wondering what the scientific hivemind thinks.
posted by citygirl at 2:26 PM on December 19, 2020 [1 favorite]


The question could be reframed as whether to get a mRNA or to wait for the AstraZeneca vaccine which works in a different way, more like older vaccines. I think that currently the mRNA vaccines seem more benign but the info that's out there is little better than gossip.
posted by SemiSalt at 5:00 PM on December 19, 2020


Frankly, antivax mentality is basically fear of the unknown. It's not logical, and you can't destroy it with logic. Most antivax propaganda focus on the yuck factor (dead babies!) and the fear factor (it can be linked to X Y and Z! -- Nope!)

Vaccine Safety Datalink has only POSITIVELY linked 33 confirmed cases of anaphylaxis triggered by vaccines... after 25 MILLION doses. That's about 1.31 per MILLION doses. It's not specific to gender, age, and so on. Most data is from flu vaccine, but then, that's the most administered vaccine. Similar data from Canada and UK.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783279/
posted by kschang at 5:08 PM on December 19, 2020


Best answer: Not a side effect per se, but the only late-to-detect negative effect of a vaccine I (a microbiologist/epidemiologist /vaccine researcher) am aware of is the dengue vaccine, which resulted in more severe disease in children in the Philippines
posted by emd3737 at 8:48 PM on December 19, 2020 [1 favorite]


Not a specific answer, but I think you'll like this xkcd.
posted by theora55 at 6:56 AM on December 20, 2020 [1 favorite]


@emd3737 -- well, if you want to count that, then yes, there are potential problems when vaccines cannot be administered as it is intended. There are some reports of polio vaccines being distributed in insufficient quantities in certain communities that may have contributed to rise of non-polio myelitis that lead to WHO to reformulate polio vaccine in recent years, from trivalent to bi-valent formula, IIRC.

But it's not a problem with the vaccine itself, but more of an unintended consequence.
posted by kschang at 5:35 PM on December 20, 2020


data point CDC confirms 6 cases of severe allergic reaction to Pfizer’s COVID vaccine — out of 272,000 shots given so far
posted by theora55 at 7:38 AM on December 21, 2020


Q. Don’t scientists need more time to study these vaccines to be sure they’re safe?
A. They watched these 64,000 people in these trials super carefully:
--They kept close track of the short-term reactions (sore arm, fatigue, etc) and saw they didn’t change over time and didn’t last.
--Some people got their shots in July and they have been followed ever since (five months) with no new side effects during that time.
--As a rule with viruses you just don’t see side effects or reactions more than few weeks after getting a vaccine
--The FDA didn’t even look at the data until an average of two months after the last dose was given
--It is possible there will be new reactions or allergic reactions seen when the vaccine is given to eight gajillion more people but so far it’s all been temporary and easily handled

Source: Dr. Robin Schoenthaler
posted by oceano at 8:01 PM on December 22, 2020


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