Report Finds Low Adverse Event Rate From COVID-19 Vaccine
CDC Updates Guidance on Vaccines, Management of Anaphylaxis
January 8, 2021, 1:38 pm Michael Devitt — Of nearly 1.9 million first doses of the Pfizer-BioNTech COVID-19 vaccine administered in the United States in the first 10 days after it received an emergency use authorization from the FDA, fewer than 4,400 adverse event reports were submitted to the Vaccine Adverse Event Reporting System, and fewer than two dozen of those reports were determined to be anaphylaxis.
Those are the main findings from an analysis of VAERS case reports published as a Morbidity and Mortality Weekly Report Early Release on Jan. 6. The report serves to remind family physicians and other health care professionals of the importance of recognizing the signs and symptoms of anaphylaxis in patients who are vaccinated against COVID-19, and also to ensure that clinicians have sufficient amounts of the supplies necessary to manage allergic reactions to vaccination in the clinic or office setting.
Sarah Coles, M.D., chair of the AAFP’s Commission on Health of the Public and Science, told AAFP News in an email that for family physicians, the take-home message from the report is that the vaccine is safe and effective, and that anaphylaxis is a rare complication.
“There was nothing in this report that was particularly concerning but (it) was a good reminder that family physicians must be prepared to recognize early signs of anaphylaxis and be prepared to treat,” Coles said.
Methods and Analysis
Authors examined 4,393 adverse event reports following administration of the Pfizer-BioNTech vaccine that were submitted to VAERS between Dec. 14-23, 2020. Of those, 175 were initially identified as possible cases of severe allergic reaction.
Story Highlights
Further review determined that
- 21 were anaphylaxis,
- 86 were non-anaphylaxis allergic reactions,
- 61 were non-allergic adverse events and
- seven were still under investigation at the time the report was published.
The overall adverse event rate was slightly more than 0.02%, and the estimated anaphylaxis rate was about 11 cases per million doses administered.
Anaphylaxis Case Reports
Of the 21 individuals in whom anaphylaxis occurred, 19 were women; the median age was 40. The most common signs and symptoms were a rash and/or hives. Most people who experienced anaphylaxis (86%) had onset within 30 minutes of receiving the vaccine, and 19 patients were treated with epinephrine as part of therapy.
The investigators also found that the majority of patients who experienced anaphylaxis after receiving the vaccine (81%) had a documented history of allergies or allergic reactions to drugs or other substances, and that one-third had experienced an episode of anaphylaxis in the past.
As to the seriousness of anaphylaxis, four people required hospitalization and the other 17 were treated in an emergency department. At the time of reporting to VAERS, 20 people had recovered or were discharged home after treatment. Perhaps most important, no deaths from anaphylaxis were reported after receiving the vaccine.
Authors’ Conclusions
The report’s authors stated that because the available data are limited, it would be difficult to compare the risks of anaphylaxis associated with the Pfizer-BioNTech vaccine with those of non-COVID-19 vaccines. Nevertheless, they said that anaphylaxis appears to be rare.
“Widespread vaccination against COVID-19 with highly effective vaccines represents an important tool in efforts to control the pandemic,” they wrote. “CDC and FDA will continue to monitor for adverse events, including anaphylaxis, after receipt of COVID-19 vaccines and will regularly assess the benefits and risks of vaccination in the context of the evolving epidemiology of the pandemic.”
Family Physician Perspective
Coles told AAFP News that while allergic reactions to the Pfizer vaccine appear more common than for other vaccines, they are still quite rare. She also said that she did not have concerns about receiving the vaccine or administering it to patients, and noted that she had already received the first dose of the vaccine herself.
“I am scheduled to receive my second dose soon, and nothing in this report gave me any pause about getting my next shot,” said Coles.
“I feel very comfortable recommending and giving the vaccine to patients,” Coles added. “The risks from COVID-19 to the patient as well as to our communities at large are significantly higher than the risk of the vaccine. The vaccine is an important step in ending the pandemic and saving lives.”
When asked about patients who are hesitant about getting vaccinated, Coles said it was understandable for people to feel nervous, and that each conversation should focus on that patient’s specific questions or concerns.
“Generally, I would focus on the safety and efficacy of the vaccine, the risks of COVID-19 infection, and the robust safety monitoring system that is in place. I encourage folks to lead with empathy, address misinformation head-on, and validate the very real fears that people are experiencing,” said Coles, adding, “Of course, these conversations are best had in the context of a trusted physician-patient relationship.”
People who are pregnant are among the patient populations that appear to be at increased risk of developing severe illness from COVID-19. Coles offered suggestions for discussing vaccination with those who are pregnant or considering pregnancy.
“There is not a lot of data on the safety of COVID-19 vaccines in pregnant persons, but the vaccine is unlikely to pose a significant risk of the pregnant person or the fetus,” Coles said. “Pregnant individuals should discuss with their family physician the risks of catching COVID-19 and what that means for their health and pregnancy, and then weigh the side effects of vaccination and the lack of data about vaccines when making their decision. All pregnant persons should be offered the vaccine when it is their turn. There is no indication to delay pregnancy after vaccination.”
Coles also recommended that FPs take specific steps to reduce the risk of anaphylaxis or other types of adverse reactions.
“Prior to vaccination, family physicians should assess their patients for a history of severe or immediate allergic reaction to a previous dose of an mRNA COVID-19 vaccine, any of its components or polysorbate,” Coles said. “These would be contraindications to vaccination. Family physicians should also be prepared to recognize early signs of anaphylaxis and be prepared to treat the patient on site.”
CDC Updates Guidance
Along with the findings from the MMWR report, the CDC on Dec. 30, 2020, issued updated interim clinical considerations for use of mRNA COVID-19 vaccines currently authorized in the United States, as well as interim considerations on preparing for the potential management of anaphylaxis following vaccination. This guidance clearly outlines the updated contraindications for individuals with known allergies to polyethylene glycol and polysorbate.
The next day, the agency updated its COVID-19 Vaccines and Allergic Reactions page with additional guidance for individuals who experience an allergic reaction after getting a COVID-19 vaccination.
Whereas the MMWR report focused only on the Pfizer-BioNTech vaccine, the updated considerations and guidance pertain to both the Pfizer-BioNTech and Moderna vaccines for COVID-19.
Recipients of the vaccine are also encouraged to enroll in V-safe, a system designed to aid in reporting symptoms, reactions, and impacts on aspects of daily life and work.