Every day, nearly 3 million people in the United States are receiving the COVID-19 vaccine. And each new injection raises new questions about what to expect after vaccination.
Last week, I asked readers to send me their vaccine questions. Here are some answers.
P: I heard that the side effects of the COVID vaccine, especially after the second dose, can be very bad. Should I be worried?
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A: Short-term side effects, such as fatigue, headache, muscle pain and fever, are more common after the second dose of the Pfizer-BioNTech and Moderna vaccines, which require two injections each. (The Johnson & Johnson vaccine requires only a single injection.) Patients who experience unpleasant side effects after the second dose often describe the feeling of having a bad cold and use phrases like “she flattened me out” or “I was useless” for two days. ”During vaccine studies, patients were advised to schedule a few days off from work after the second dose if they needed to spend a day or two in bed.
The data collected from v-safe, the app that everyone is encouraged to use to track side effects after vaccination, also shows an increase in side effects reported after the second dose. For example, about 29% of people reported fatigue after the first injection of Pfizer-BioNTech, but it increased to 50% after the second dose. Muscle pain increased from 17% after the first injection to 42% after the second. Although only about 7% of people experienced chills and fever after the first dose, this increased to about 26% after the second dose.
The New York Times interviewed several dozen newly vaccinated in the following days. They reported a wide spectrum of responses, from no reaction to symptoms like uncontrolled tremors and “brain fog”. While these experiences are not pleasant, they are a sign that your own immune system is building a potent response to the vaccine.
P: Is it true that women are more likely to have worse side effects with the vaccine than men?
A: An analysis of the first 13.7 million doses of the COVID-19 vaccine administered to Americans found that side effects were more common in women. And although severe reactions to the COVID vaccine are rare, almost all cases of anaphylaxis, or life-threatening allergic reactions, have occurred in women.
The finding that women are more likely to report and experience unpleasant side effects with the COVID vaccine is consistent with other vaccines as well. Women and girls can produce up to twice as many antibodies after receiving flu and measles, mumps and rubella (MMR) and hepatitis A and B vaccines. One study found that in almost three decades, women accounted for 80% of all adult anaphylactic reactions to vaccines.
While it is true that women may be more likely to report side effects than men, the higher rate of side effects in women also has a biological explanation. Estrogen can stimulate an immune response, while testosterone can attenuate it. In addition, many genes related to the immune system are on the X chromosome, of which women have two copies and men only one. These differences may help explain why many more women than men suffer from autoimmune diseases, which occur when a robust immune response attacks healthy body tissue.
Q: I had no side effects. Does this mean that my immune system has not responded and the vaccine is not working?
A: Side effects get all the attention, but if you look at data from clinical vaccine tests and the real world, you will see that many people do not experience any side effects other than a sore arm. In the Pfizer vaccine tests, about 1 in 4 patients reported no side effects. In the Moderna tests, 57% of patients (64 or younger) reported side effects after the first dose – which increased to 82% after the second dose, meaning that almost 1 in 5 patients reported no reaction after the second dose. .
The lack of side effects does not mean that the vaccine is not working, said Dr. Paul Offit, a professor at the University of Pennsylvania and a member of the Food and Drug Administration’s vaccine advisory panel. Offit noted that, during the vaccine tests, a significant number of people did not report side effects, and yet the tests showed that about 95% of the people were protected. “It proves that you don’t have to have side effects to be protected,” he said.
No one really knows why some people have so many side effects and none at all. We know that younger people develop stronger immune responses to vaccines than older people, whose immune systems become weaker with age. Women generally have stronger immune responses than men. But, again, these differences do not mean that you are not protected if you do not feel much after receiving the injection.
Scientists are still unsure of the effectiveness of vaccines in people whose immune systems may be weakened by certain medical conditions, such as cancer treatments or HIV infection, or because they are taking immune-suppressing drugs. But most experts believe that vaccines still offer these patients some protection against COVID-19.
The end result is that, although individual immune responses may vary, the data collected so far shows that all three vaccines approved in the United States – Pfizer-BioNTech, Moderna and Johnson & Johnson – are effective against serious illness and death by COVID- 19.
P: I took Tylenol before taking my COVID vaccines and had very little reaction to the injections. Did I make a big mistake?
A: You should not try to avoid discomfort by taking a pain reliever before receiving the injection. The concern is that premedication with an analgesic like paracetamol (Tylenol) or ibuprofen (Advil, Motrin), which can prevent side effects such as arm pain, as well as fever or headache, can also decrease the immune response of your body.
While it is possible that taking a painkiller before injections may have lowered your body’s immune response, vaccine experts say you shouldn’t worry and shouldn’t try to take another round of substitute injections. Studies with other vaccines suggest that, although premedication may dull the body’s immune response to a vaccine, its immune system can still build up a defense strong enough to fight infection. A review of studies with more than 5,000 children compared the levels of antibodies in children who took painkillers before and after vaccination and those who did not. They found that painkillers did not have a significant impact on the immune response and that children in both groups generated adequate levels of antibodies after vaccines.
The high effectiveness of all COVID vaccines suggests that even if taking Tylenol before the injection has dampened your body’s immune response, there is some leeway and you are probably still well protected against COVID-19. “You must feel confident that you will have an immune response sufficient to be protected, especially for vaccines that are so good,” said Offit.
P: How about taking a painkiller after the injection?
A: “It’s okay to treat” side effects with a painkiller, said Offit, but if you really don’t need one, “don’t take it.”
Although most experts agree that it is safe to take a pain reliever to relieve discomfort after vaccination, they advise against taking it after the injection as a preventative or if the symptoms are manageable without it. The concern with taking an unnecessary pain reliever is that it can mitigate some of the vaccine’s effects. (In terms of the vaccine, there is no significant difference if you choose acetaminophen or ibuprofen.)
During the Moderna trial, about 26% of people took acetaminophen to relieve side effects, and the overall effectiveness of the vaccine was still 94%.
Q: Are the side effects worse if you have already taken COVID-19?
A: Research and anecdotal reports suggest that people with previously diagnosed COVID-19 infection may experience a stronger reaction and more side effects after the first dose of the vaccine compared to those who have never been infected with the virus. A strong reaction to your first dose of the vaccine can also be a sign that you have already been infected, even if you are not aware of it.
If you tested positive for COVID-19 previously or had a positive blood test for antibodies, be prepared for a stronger reaction to your first dose and consider scheduling a few days off from work to be sure. Not only will it be more comfortable to stay home and recover in bed; the side effects of the vaccine can be similar to the symptoms of COVID-19, and your coworkers won’t want to be around you anyway.
Q: I already had COVID-19. Does this mean that I can take just one dose?
A: Studies suggest that a dose may be appropriate for people who have a previously confirmed case of COVID-19, but so far, medical guidelines have not changed. If you have received the Pfizer-BioNTech or Moderna vaccines, you should plan to receive your second dose, even if you have taken COVID-19. Skipping the second dose can create problems if your employer or an airline asks to see proof of vaccination in the future. If you live in an area where a Johnson & Johnson single dose vaccine is available, you can be fully vaccinated after just one dose.
Q: Will vaccines work against new variants that have emerged around the world?
A: Vaccines appear to be effective against a new variant that originated in Britain and is rapidly becoming dominant in the United States. But some variants of the coronavirus, particularly one first identified in South Africa and one in Brazil, appear to be more adept at avoiding antibodies in vaccinated people.
Although it seems worrying, there are reasons to hope. Vaccinated people exposed to a more resistant variant still appear to be protected from serious illnesses. And scientists have a clear enough understanding of the variants that they are already working on developing reinforcement shots that will target the variants. The variants identified in South Africa and Brazil are not yet widespread in the United States.
Vaccinated people should still wear masks in public and comply with public health guidelines, but you shouldn’t live in fear of the variants, said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston. “If you get vaccinated, you should feel very confident about how you are protected,” said Hotez. “It is unlikely that you will go to a hospital or ICU with COVID-19. Over time, you will see a recommendation for reinforcement ”.
This article was originally published in The New York Times.
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