- Moderna clinical trials found that the most commonly reported symptoms after injection were injection site pain, fatigue, headache, and soreness.
- Millions of people got the vaccine out of the trial, and the top side effects included pain at the injection site with chills, headache, and fever.
- In general, older adults are less likely to experience side effects after vaccination.
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More than 47 million doses of the Moderna vaccine have been given to adults in the US since FDA approved emergency use on December 18, 2020.
Moderna clinical trials found that the most commonly reported symptoms after injection were injection site pain, fatigue, headache, and soreness.
Now, with so many doses of the vaccine being given, we can have a clearer picture of the side effects of the Moderna vaccine.
As with participants in clinical trials, people often report pain at the injection site with chills, headache, and fever.
There have also been some reports of “COVID arms” after vaccination with Moderna, rashes appearing on the skin that may have been caused by ingredients in the vaccine.
Reactions are usually more intense after the second dose and in people who have had COVID-19 before.
Infectious disease doctors say these reactions are possible, as they show that the immune system is working to learn to recognize and fight the coronavirus.
The most common side effects after injection of Moderna
Pain at the injection site, chills, headache, and fever are the most common symptoms people experience after getting the Moderna vaccine.
All of these reactions are temporary and not dangerous, but show that the vaccine is doing its thing. These reactions usually resolve within a few days.
“Because vaccines ‘train’ the immune system to start making antibodies,” said Dr. Shobha Swaminathan, an associate professor at Rutgers University School of Medicine in New Jersey and clinical trial leader for the Rutgers Moderna trial. body, so pain is a sign of inflammation, which happens as part of this process.”
As with other vaccines, each person’s response may be slightly different.
In general, older people are less likely to experience side effects after getting the vaccine.
Recent data suggest that women tend to experience more adverse events following vaccination.
It’s not clear exactly why side effects may vary between sexes. Some health professionals suspect that women are more likely to report side effects, while others believe there is a biological component at play.
Some people have also reported a skin rash at the injection site on the arm – known as the COVID arm.
“This is a fairly common side effect and is probably related to ingredients in vaccines that teach the immune system that something is wrong,” explains Anne Liu, an infectious disease physician at Stanford Health Care. danger is being introduced”.
Anaphylaxis is a rare and serious allergic reaction. Anaphylaxis is also more common in women.
More severe reactions after the second dose and in people with COVID-19
Moderna is a messenger RNA (mRNA) vaccine that teaches our cells the structure of a SARS-CoV-2 protein fragment and induces an immune response against it.
That way, if a person is exposed to the coronavirus, their body will know how to fight it and prevent serious illness.
According to Swaminathan, the first injection is considered the “main dose” and trains your body to recognize the virus.
“Since it is the first exposure, reactions tend to be mild,” says Swaminathan.
The second dose, the “booster dose,” further strengthens the immune response.
“Since the patients ‘received’ the vaccine from the first shot, the second booster shot is an exaggerated response to the same vaccine,” says Swaminathan.
The study also showed more intense reactions in people who had previously had COVID-19 because they likely had some degree of pre-existing immunity.
How do Moderna’s reactions compare to other injections?
Reactions to Moderna vaccine were similar to those reported following administration of Pfizer vaccine, also an mRNA vaccine.
People who received both the Moderna and Pfizer mRNA vaccines often reported injection site pain and redness after the first dose, along with fatigue and joint pain after the second dose.
“Reactions to mRNA vaccines are not so different, certainly not to the extent that an individual should choose one or the other based on side effects,” says Liu.
In clinical trials, Johnson & Johnson injections were associated with milder side effects than mRNA injections.
“Since Moderna and Pfizer require two shots and most of the side effects are from the second shot, the J&J vaccine may have slightly fewer side effects,” Swaminathan said.
With more than 47 million doses of Moderna vaccine administered in the US, we are getting a clearer picture of the types of side effects that can occur after vaccination.
Usually, people have injection site pain and redness after the first dose, along with fatigue and joint pain after the second dose.
Reactions tend to be more intense after the second dose and in people who have had COVID-19 before.
Reactions will be possible, and show that the vaccine is teaching the immune system how to recognize and fight the coronavirus.
Translated by: Vy Nguyen
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