Les effets secondaires sont généralement plus prononcés chez les femmes et les jeunes adultes, en particulier après leur deuxième dose - à moins qu'ils n'aient déjà eu COVID-19. </p><div> <ul class="summary-list"><li>Les effets secondaires du vaccin COVID-19 peuvent varier en fonction de l'âge, du sexe ou de l'état de santé d'une personne.</li>
When Freedom Baird received her first dose of Moderna vaccine in February, she wasn’t sure what kind of side effects to anticipate.
Baird is a long-haul COVID-19 – she has had persistent shortness of breath and chest pain for about a year. Many people who have had an infection in the past develop more side effects in response to the first dose of vaccine than to the second. An average person, on the other hand, usually feels more run down after their second stroke.
Baird’s age complicated her expectations: She’s 56, and clinical trials have shown that people over 55 often develop fewer side effects from vaccines. In the end, she didn’t feel much.
“It was really just that first day of pain and flu,” Baird told Insider.
While doctors can’t predict exactly how a person will respond to a coronavirus vaccine, they have identified a few patterns based on a person’s age, sex, medical condition, and dose. Clinical trials suggest that side effects are generally more pronounced in women and young adults, especially after their second dose.
The second dose is usually accompanied by more serious side effects
The most common side effect for the three licensed U.S. vaccines is pain or swelling at the injection site: nearly 92% of Moderna clinical trial participants developed this side effect. in the Pfizer trial, 84% of participants reported this, as did 49% in Johnson & Johnson.
Other common side effects include fatigue, headaches, and muscle aches or pain. About 65% of those vaccinated in the Pfizer and Moderna trials, and 38% at Johnson & Johnson, developed fatigue.
For those who have never had COVID-19 before, side effects tend to be more numerous and more severe after the second dose.
About twice as many participants in the Pfizer trial developed chills and joint pain after their second dose than after the first. In Moderna’s trial, meanwhile, about five times as many participants developed chills after their second dose than their first. Fevers were also much more common in second dose recipients than in first dose recipients in both trials.
People who have had COVID-19 may develop more side effects after dose 1
A small study from the Icahn School of Medicine at Mount Sinai found that vaccine side effects such as fatigue, headaches and chills were more common in people with pre-existing coronavirus immunity than in people who didn’t. had never been infected before. About 73% of vaccinees who had previously had COVID-19 developed side effects after the first dose of Pfizer or Moderna’s vaccine, compared with 66% of vaccinees who had never been infected before.
“If you’ve ever had a COVID-19 infection, you’ve developed memory cells from that infection,” Baltimore-based doctor Vivek Cherian, Dr. Vivek Cherian, told Insider.
“If you were ever exposed to the infection again, your body would actually be able to respond quickly and more vigorously the second time around,” he added. “That’s why you tend to have stronger side effects with this initial vaccine. ”
Young adults may feel more run down after their injections than older people
Our immune systems gradually deteriorate as we age, which means that older people’s bodies don’t work as hard to defend them against foreign invaders – including the protein introduced into the body via a vaccine.
“Young individuals have a much more vigorous immune response, so it should make sense that they also have more side effects,” Cherian said.
After an injection dose of Moderna, 57% of people under 65 developed side effects, compared to 48% of those over 65. After the second dose, almost 82% of people in the younger group developed side effects, compared to almost 72% of older adults.
Pfizer broke down their data slightly differently: About 47% of people aged 18 to 55 developed fatigue after the first dose, while 34% of people aged 56 and older reported this side effect. After the second dose, the numbers jumped to 59% and 51%, respectively.
After Johnson & Johnson’s one-shot vaccine, nearly 62% of people aged 18 to 59 developed side effects, compared to 45% of people aged 60 and over.
Women can expect more side effects in general
The Centers for Disease Control and Prevention analyzed Americans’ reactions to nearly 14 million doses of Pfizer and Moderna injections from December through January. The results showed that about 79% of the cases of vaccine side effects reported to the CDC were from women, although only 61% of the doses were given to women overall.
Cherian said women also tend to respond more strongly to polio, flu, measles and mumps vaccines.
“All of these vaccines in general women tend to have more severe side effects,” he said. “They are even more pronounced for a pre-menopausal woman compared to a post-menopausal woman. ”
Scientists suspect the difference is related to estrogen levels.
“Testosterone tends to be an immunosuppressive hormone and estrogen tends to be an immune booster,” Cherian said. “So it’s more than likely to be the hormone estrogen – which is why women tend to have more side effects. ”
Most high risk medical conditions will not lead to stronger side effects
People with weakened immune systems are not a strong defense against viral infections in general, so they are particularly vulnerable to severe COVID-19. For this reason, the CDC recommends that these groups be vaccinated immediately.
But it is possible that people who are immunocompromised, such as cancer patients, also do not develop a strong immune response to the vaccine.
“Your immune response basically dictates your side effects, so if you’re immunocompromised you can’t necessarily have that many side effects, but you still absolutely have to get the vaccine,” Cherian said.
Vaccines should provide immunocompromised people with at least some protection against severe COVID-19, even if they don’t experience any side effects – although the effectiveness may be less than that of the average person.
Cherian said that for people with autoimmune diseases, the side effects are unlikely to be worse than for the average person.
“If you have these high risk factors, you really, really want to get the vaccine,” he said. “Dealing with a few side effects of certain diarrhea or muscle pain is a lot better than some of these serious and life-threatening side effects of COVID-19 infection. ”