- The Moderna
clinical trials found that pain, fatigue, headache, and injection site pain were commonly reported after vaccination. - Since millions of people have received the vaccine outside of the trials, the main side effects are injection site pain, chills, headache, and fever.
- In general, older adults are less likely to have side effects after vaccination.
More than 47 million doses of the Moderna vaccine have been administered to American adults since the FDA
The Moderna
Now that so many shots have been fired in the arms, we’ve been able to get an even clearer picture of the side effects the Moderna vaccine causes.
Like those involved in the clinical studies, people often reported injection site pain along with chills, headaches, and fever.
There have also been several reports of “COVID arm” after the Moderna vaccination, a harmless skin rash likely caused by the ingredients of the vaccine.
The reactions are usually more severe after the second dose and in people who have previously developed COVID-19.
Infectious disease doctors say these reactions are to be expected because they indicate that the immune system is doing its job by learning to recognize and fight the coronavirus.
Injection site pain, chills, headache, and fever are the symptoms
All of these responses – which are temporary and non-threatening – indicate that the vaccine is working. They usually disappear within a few days.
“Because the vaccine works to ‘train’ your immune system to develop antibodies, the pain is a sign of the inflammation that occurs as part of this process,” said Dr. Shobha Swaminathan, associate professor of medicine at Rutgers New Jersey Medical. Leader of school and clinical research for the Rutgers Moderna study.
As with other vaccines, each person’s response can be slightly different.
In general, older adults are less likely to have side effects after vaccination.
It’s unclear why side effects may differ between genders. Some health experts suspect that women are more likely to report side effects, while others believe there is a biological component.
Several people have also reported a rash on the arm where they received the injection – also known as COVID arm.
“This is a fairly common side effect and probably has to do with the ingredients in the vaccine that are designed to teach the immune system that something dangerous is being introduced,” explains Dr. Anne Liu, infectious diseases physician at Stanford Health Care.
Anaphylaxis, a severe allergic reaction, appears to be rare. Anaphylaxis also appears to be
The Moderna shot is a messenger RNA (mRNA) vaccine that teaches our cells to make a piece of SARS-CoV-2 protein and build an immune response against it.
That way, if a person were exposed to the coronavirus, their body would already know how to fight it and prevent serious illness.
The first dose is considered “the prime” and trains your body to recognize the virus, Swaminathan said.
“Since that’s the first exposure, the reactions are usually mild,” said Swaminathan.
The second dose, the “booster”, further enhances the immune response.
“Since the patients have ‘seen’ the vaccine from the first injection, the second booster is an exaggerated reaction to the same thing,” Swaminathan said.
Research also suggests that responses are more intense in people who have previously had COVID-19, as they likely have some level of pre-existing immunity.
Responses to the Moderna vaccine are similar to those reported after the Pfizer vaccine, which is also an mRNA vaccine.
Recipients of 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.
“The responses to the mRNA vaccines were not very different, certainly not to the extent that an individual would have to choose one or the other based on side effects,” said Liu.
In clinical studies, the Johnson & Johnson injection was associated with milder side effects compared to the mRNA shots.
“Since Moderna and Pfizer require two injections and most side effects were from the second injection, the J&J vaccine may have slightly fewer side effects,” Swaminathan said.
With more than 47 million doses of the Moderna vaccine given to Americans, we are getting a clearer picture of the types of side effects that can occur after vaccination.
Typically, people experience injection site pain and redness after the first dose, along with fatigue and joint pain after the second dose.
Reactions are usually more severe after the second dose and in people who have previously received COVID-19.
The responses are to be expected and indicate that the vaccine is doing its job by teaching the immune system to recognize and fight the coronavirus.