What side effects (mild) can the COVID-19 vaccine cause depending on your age, gender and dose?

With the spread of vaccination around the world and the prospect of getting herd immunity back to normal is still a distant possibility, much has been speculated about the effects vaccines cause in people who receive them.

Although these effects are temporary and vary from person to person, no risk factor significant enough has been identified so far for someone to choose not to get the vaccine and remain exposed to it. virus that has caused millions of deaths around the world.

What the scientists were able to determine are some models depending on a person’s age, sex, state of health and the dose they are receiving to get an idea of ​​what these possible side effects may be.

For example, clinical trials suggest that side effects are generally more pronounced in women and young adultsespecially after the second dose.

1-The second dose usually has stronger side effects

The most common side effect of the three licensed US 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 said this, as did 49% in the Johnson & Johnson trial.

Other common side effects include fatigue, headaches, and muscle aches or pain.. About 65% of those who received the vaccine in the Pfizer and Moderna trials, and 38% in the Johnson & Johnson trials, developed fatigue.

For those who have never had COVID-19 before, side effects tend to be more numerous and more serious after the second dose.

About twice as many Pfizer trial participants they developed chills and joint pain after the second dose than after the first. Meanwhile, in Moderna’s trial, about five times as many participants developed chills after the second dose than the first.

Fever was also much more common in those who received the second dose than in those who received the first dose in both trials.

2- People who have already had COVID-19 may develop more side effects after the first dose

A small study from the Icahn School of Medicine on Mount Sinai found that the side effects of the vaccine, like fatigue, headaches, and chills, were more common in people with pre-existing immunity coronavirus than among people who have never been infected before.

About 73% of vaccinees who had previously had COVID-19 developed side effects after a dose of Pfizer or Moderna, compared to 66% of vaccinees who had never been infected before.

“If you have ever had a COVID-19 infection, you have developed memory cells from that infection”, Dr Vivek Cherian, an internal medicine doctor from Baltimore, told Insider.

“If you were ever exposed to the infection again, your body would essentially be able to respond faster and more vigorously this second time around. That’s why he tends to have stronger side effects with this initial vaccine, ”he added.

3- Young adults may feel more exhausted after being vaccinated 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 proteins introduced into the body through a vaccine.

“Young people have a much stronger immune response, so it should make sense that they also have more side effects.Said Cherian.

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, nearly 82 percent of people in the younger age group developed side effects, compared to almost 72 percent 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 increased to 59 percent and 51 percent, respectively.

After Johnson & Johnson’s single-shot vaccine, nearly 62% of people aged 18 to 59 developed side effects, compared to 45% of people 60 and older.

4- 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 these vaccines in general, women tend to have more serious side effects”, He said. “They are even more pronounced for a premenopausal woman compared to a postmenopausal 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. So it’s probably the hormone estrogen, which is why women tend to have more side effects ”, Said Cherian.

5- Most high risk medical conditions will not lead to stronger side effects

People with weakened immune systems do not have a strong defense against viral infections in general, making them particularly vulnerable to severe COVID-19. For this reason, the CDC recommends that these groups be vaccinated immediately.

But immunocompromised people, such as cancer patients, may not induce a strong immune response to the vaccine either.

“Your immune response basically dictates your side effects, so if you’re immunocompromised you won’t necessarily have that many side effects, but you still need to get the vaccine.” Said Cherian.

Vaccines should give immunocompromised people 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.

“Treating some side effects of certain diarrhea or muscle pain is much better than some of these serious and life-threatening side effects of COVID-19 infection,” concluded.

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