Key takeaways:
The most common side effects after receiving the COVID-19 vaccine are injection site reactions, fever, headache, chills, fatigue, muscle aches, and nausea.
Serious reactions are very rare but include anaphylaxis, thrombosis with thrombocytopenia syndrome, Guillain-Barré Syndrome (GBS), and myocarditis or pericarditis.
The vaccine’s potential benefits outweigh the potential risks in the vast majority of cases, and providers should recommend COVID-19 vaccination to most patients.
There are currently four COVID-19 vaccines available in the U.S.: Pfizer-BioNTech, Moderna, Janssen (by Johnson & Johnson), and Novavax.
Healthcare providers, or HCPs, are the main driver of the massive effort to distribute COVID-19 vaccinations. So it’s important for them to understand the possible side effects, allergic reactions, and anaphylactic reactions that patients may experience.
Side effects and adverse reactions
Here’s a rundown of the most common side effects and serious reactions patients may have.
Side effects
While side effects from all vaccines are common, not all vaccine recipients experience them. Most side effects of COVID-19 vaccines show up within 1 to 2 days and last for 1 to 2 days. Patients who have mild side effects for more than 1 or 2 days may need a COVID-19 test to rule out infection.
When discussing anticipated side effects with patients, emphasize that side effects may be more intense after the second shot.
Typical side effects of the COVID-19 vaccine include:
Pain, redness, and swelling at the injection site
Fever
Headache
Chills
Fatigue
Muscle aches
Nausea
Adverse reactions
Patients who experience a severe allergic reaction to the COVID-19 vaccine (meaning they need epinephrine), should not receive the same type of COVID-19 vaccine in the future. But they may be able to receive another type of COVID-19 vaccine.
Adverse reactions are extremely rare and usually happen in the first 6 weeks. However, it’s sometimes difficult to establish a link between the vaccine and the reported adverse reaction.
Adverse reactions include:
Thrombosis with thrombocytopenia syndrome: This reaction has occurred in about 4 out of every 1 million doses of the Johnson & Johnson vaccine that were administered.
Guillain-Barré Syndrome (GBS): This reaction is very rare. But the rate of GBS is significantly higher with the Johnson & Johnson vaccine than it is with Pfizer-BioNTech or Moderna. There appears to be no risk of developing GBS with those vaccines.
Myocarditis and pericarditis: This is also a very rare reaction. It has been reported mostly in young males after receiving the Pfizer-BioNTech or Moderna vaccines.
While death has been reported after COVID-19 vaccine administration, it is extremely rare. And there is no established link between COVID-19 vaccination and death. Out of over 600 million doses administered, there have been about 15,800 preliminary reports of death. That is a rate of 0.0026%.
Anaphylaxis
While anaphylactic reactions might have made headlines on the news, they are also exceedingly rare.
Moderna had 10 total cases of anaphylaxis from the more than 4 million first doses of the vaccine, while Pfizer had 21 cases out of nearly 1.9 million first doses of the vaccine.
The onset of anaphylactic symptoms typically occurs within 15 to 30 minutes of vaccination but can also occur up to a few hours afterwards.
Although this response is rare, HCPs should be aware of the commonalities between patients who have had anaphylaxis as a result of receiving the vaccine.
Of the patients who received the Pfizer vaccine, 81% of those who experienced an anaphylactic reaction had a history of the condition or allergic reactions. Moderna had similar findings, with 50% of patients who experienced the anaphylactic reactions having a history of anaphylaxis. At this time, there have been no reports of vaccine-related deaths due to an anaphylactic reaction.
Important administration information
The CDC offers screening tools and other helpful information, including “What to Expect After Getting the Vaccine?” These can serve as educational resources for patients. The CDC also has a pre-screening tool for determining potential contraindications and risks for allergic reactions. You can access their full list of resources here.
In addition, the CDC recommends:
Screening recipients for contraindications and precautions
Making sure HCPs are ready to respond to any allergic reactions or anaphylaxis
Having established post-vaccination periods to monitor for reactions
Vaccine supplies
In addition to the supplies needed to give the shot, the following items must be available at all times:
Epinephrine (at least 3 doses)
H1 antihistamine
Blood pressure monitor
Timing device for pulse assessments
Extra items that are not required, but should be available if possible, include:
Pulse oximeter
Oxygen
Bronchodilator
H2 antihistamine
Intravenous fluid
Intubation kit
CPR mask for adults and children
Post-vaccination monitoring
The time period for post-vaccination monitoring will vary by patient history. While the CDC recommends a 15-minute observation period for most people, they recommend a 30-minute observation window for those who:
Have a contraindication to a different COVID-19 vaccine than the one being administered
Had a non-severe, immediate allergic reaction to a previous COVID-19 vaccine
Have a history of an allergic reaction to any other vaccine or injectable
Have any history of anaphylaxis, regardless of the cause
Anyone administering COVID-19 vaccines is required to report administration errors, cases of multisystem inflammatory syndrome, serious adverse events, and cases of COVID-19 that result in hospitalization or death to the Vaccine Adverse Event Reporting System, or VAERS. Anyone else, including patients, can also voluntarily submit a report.
The bottom line
Why trust our experts?
Serious COVID-19 vaccine side effects and adverse reactions are rare. And most side effects are similar to those reported with other types of immunizations. HCPs should be aware of potential side effects and serious adverse reactions and prepare to manage them, as well as educate patients. However, the COVID-19 vaccine is still highly recommended for most people, especially those at high risk of serious complications from the disease.
