Here we are, finally on the cusp of our long-awaited Hot Vaxx Summer. About 112 million people in the U.S. have received at least one dose of a COVID-19 vaccine, and if you haven’t gotten one yet, chances are you will be able to soon: Starting April 19, the general public over 16 will become eligible. Among people who are enthusiastic about vaccination, there’s a mix of excitement—after more than a year of living through the pandemic, some light at the end of the tunnel!—along with some nervousness about side effects. Some who have been lucky enough to be vaccinated already have reported chills, fevers, fatigue, or even vomiting after receiving a vaccine dose. (Side effects are more common after the second dose of the Pfizer or Moderna vaccines.)
As a result, people are getting all sorts of advice about what to do—or not to do—in the hours leading up to and following a COVID-19 vaccination. Slate staffers report receiving general advice, like staying hydrated or avoiding alcohol. Meanwhile, my parents were advised to adhere to a very specific routine: Drink one glass of water before the shot with three days’ worth of Vitamin C supplements, then one glass of water after.
Other advice, especially around taking over-the-counter painkillers like ibuprofen or acetaminophen has been contradictory.* One friend told me the nurse who administered her shot told her to take ibuprofen afterward; meanwhile, on social media, people have posted about taking pain meds even before their vaccination appointment, in hopes it could head off soreness at the injection site or muscle aches. But others tell me they’ve heard to specifically avoid ibuprofen and use acetaminophen instead, or advised to avoid pain killers entirely. What does the science say?
To understand that, it’s worth reviewing what vaccines actually do. While the Pfizer and Moderna vaccines use a different method from Johnson & Johnson’s vaccine, the result is the same: The vaccine teaches your immune system to recognize coronavirus. In that process, your body recruits specific types of cells to identify and clean up invader cells. One type of cell, called helper T-cells, aids another, called B-cells, which release antibodies that target coronavirus. Essentially, the vaccines serve as a rehearsal for your immune system to practice how to spot and clear coronavirus cells, so that if it encounters the real thing, it’s ready.
A natural part of that process is inflammation, says Sujan Shresta, a viral immunologist at the La Jolla Institute for Immunology. “For proper development of the immune system, there needs to be the right balance of molecules called cytokines, which help the T cells and B cells be fully activated,” she says. Non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen, get rid of some inflammatory cytokines, which may reduce activation of immune cells and antibody responses. Though there is limited data, Shresta says, “most scientists and physicians will advocate for not taking anything if at all possible.”
That’s what Rachel Roper, associate professor of microbiology & immunology at East Carolina University, told me as well. Taking over-the-counter painkillers before the vaccine is definitely unnecessary—after all, you won’t know until after the shot if you’ll have any unpleasant response. “All these side effects you get are basically a reaction to your immune response turning on, so it doesn’t seem like a good idea to take something that blocks that,” says Roper. “If it’s two days after the vaccine and you’ve still got chills and high fever, then I think it might be reasonable to take it, because you’ve got an overreaction—but I wouldn’t take it before, and I wouldn’t take it a day after either, unless you’re really miserable.”
But if you do end up taking over-the-counter painkillers with your vaccine—or already did—it’s probably not a huge deal. The overall effect of NSAIDs is likely pretty small. Among the small body of existing studies looking at the effect of NSAIDs on post-vaccine antibody production in children, researchers did find some evidence of reduced antibody responses, but that did not affect the efficacy of vaccines. A 2009 paper examining the effect of OTC painkillers in mice and human cells in a lab found a similar result: Ibuprofen, but not acetaminophen, dampens antibody responses. But, of course, humans are not mice, and our cells may behave differently when they’re actually inside of us rather than in a petri dish. “This is not an FDA-sanctioned clinical trial that shows [NSAIDs] have an effect on vaccinations, which is what you really need to do,” says David Topham, a co-author of that study and a professor of microbiology and immunology at the University of Rochester. “I think if they did the trial, the effect would be modest.” Still, based on his results, Topham says that if he had a choice, he’d take acetaminophen and not ibuprofen. And, if it makes you feel any better, Shresta told me she actually caved and took some ibuprofen the day after her second vaccine dose. “I had a major deadline the next day and with the headache, there was no way that was going to happen,” she says. Life happens.
As for the other advice—staying hydrated, avoiding alcohol, or taking vitamin supplements—there simply isn’t good data on it yet. These vaccines are still quite new, and scientists have (rightfully) been focused on testing its overall efficacy, rather than examining the effect of these other variables. While there’s some data suggesting alcohol can inhibit immune responses, it’s unlikely that any single behavior is going to strongly affect your vaccine’s efficacy.
Rather, all this advice centers around putting your immune system’s best foot forward. Roper recommends getting a good night of sleep before getting vaccinated and not doing a super hard workout the day before or after. (This was the point in our phone call where I had a moment of panic that I’d done it wrong: I tried a hard running workout the day after my first dose, but Roper said it was probably fine.) Stay hydrated and eat well, of course, but there’s no need to go out of the way to drink a ton of water or vitamin C supplements; neither has any particular effect on your immune system. Perhaps one upside of prescribing this kind of routine to patients is a type of placebo effect—it makes people feel like they’re prepared, and can reduce anxiety about going to their appointment. Maybe, Roper said, my parents’ doctor told them this just to make them feel better.
The bottom line that all researchers stressed? Just go get the vaccine. Avoid over-the-counter painkillers and alcohol if you can, but at the end of the day, the best thing you can do for yourself—and our society, which is struggling to control the spread of COVID—is to get the shot when you’re able. “The world is really at a critical phase with these variants, and we need everyone to be vaccinated as quickly as possible,” says Shresta.
Correction, April 12, 2021: This article originally misidentified acetaminophen as a nonsteroidal anti-inflammatory drug. It is not.