Recent Findings Highlighted on Management of Allergic Reactions to COVID-19 Vaccines

Credit: Institute of Coaching

An analysis of the management of allergic reactions related to COVID-19 vaccination has been conducted, with findings highlighting several important points related to risk, guidelines, and recommendations.¹

The new analysis of COVID-19 vaccine-related reactions were summarized by a team led by Mary Johnson, from the department of environmental health at Harvard T. H. Chan School of Public Health.

Following COVID-19 vaccine rollouts of recent years, new challenges necessitating efficient and successful clinical management have become necessary. Rates of anaphylaxis induced by COVID-19 rate are noted as 10.67 cases/million vaccine doses and similar to rates of traditional vaccines.²

“Early reports of anaphylaxis reactions led to a risk management strategy that stratified patients based on their prior history of potential reactions to excipients of or existing mRNA vaccines,” Johnson and colleagues wrote. “As the vaccine roll out continued, findings suggested that severe allergic reactions are much rarer than initially reported.”¹

Analysis of Recent Findings

The research team noted that revisions to guidelines have recently been released for the purposes of aligning with current evidence. In June 2023, the US Food and Drug Administration (FDA) withdrew the Emergency Use Authorization for the Janssen vaccine, which had been advised previously for those with allergies to poly(ethylene) glycol (PEG) or polysorbate 80 (PS80).

In the initial vaccine rollout, information on anaphylactic reactions led to a patient stratification strategy during which individuals were categorized based upon prior reactions to vaccine ingredients or mRNA vaccines. Over time, these investigators highlighted that severe allergic reactions had been less common than initially suggested.

An 8-week-long analysis which had monitored subjects pre-identified as being at a high level risk involved 429 individuals who were observed for 2 hours following their vaccinations. It was reported that 2.1% of these subjects experienced immediate reactions, with the team adding that most had been mild and only 3 reported anaphylaxis. These 3 had their condition resolved with epinephrine without any hospitalization necessary.

In an analysis in Spain, 7,088 healthcare workers had been analyzed and 139 reported allergic reactions. These were noted as being predominantly among females with a history of allergies, with reactions having been 51% local and 49% systemic. Later dose-associated reactions were largely less severe.

Additionally, findings from a study out of Kaiser Permanente Southern California involving 391,123 subjects suggested that 0.028% had reactions following their first dose, with only 2 cases having been classified as anaphylaxis. These allergic reactions were also shown to be more common following the beginning dose, with the research team noting that risk rose if subjects were given different mRNA vaccines.

Assessment of PS80 and PEG allergies continues to be urged for those with known allergic reactions to drugs containing such substances, although its usefulness has been debated. An analysis assessing PEG and PS80 by using skin testing led to positive findings among 12.7% of those evaluated, with no major distinctions noted between those who had been tested prior to and following vaccination (10.6% versus 17.1%).

In a different analysis, positive results following skin testing were reported among a small portion of those who were both pre-vaccination (0.02%) and those who were post-vaccination (7.1%). Reactions such as immediate allergies and anaphylaxis were shown to have taken place mainly post-vaccination.

In a Spanish healthcare worker study, only a single subject had a positive patch test for PEG. This led to the conclusion that although testing for PEG and PS80 can be helpful, the application of such tests may need limits to situations in which there is a clinical basis for a suspected allergy.

Additional Conclusions

Organizations like the FDA, CDC, and European Medicines Agency have, since 2021, updated their available recommendations for the handling of COVID-19 vaccine-associated allergic reactions based upon the emerging data. While certain factors may raise the likelihood of anaphylaxis with mRNA vaccines, it was highlighted that no definitive risk factors have been established.

Additionally, one’s allergy history does not necessarily warrant split-dosing, premedication, or additional precautions before one’s vaccination.

“Severe allergic reactions to COVID-19 vaccines remain exceedingly rare, and the mechanism of these reactions requires further investigation,” they concluded. “All vaccine sites should continue to observe all individuals regardless of their risk and have staff trained in recognizing and managing anaphylaxis.”¹

References

1. ^{Johnson, M., Kline, O., Torres Jaen, M.J. and Nadeau, K.C. (2024), Algorithms in allergy: Management of allergic reactions to COVID-19 vaccines. Allergy. https://doi.org/10.1111/all.16358.}
2. ^{Maltezou HC, Anastassopoulou C, Hatziantoniou S, Poland GA, Tsakris A. Anaphylaxis rates associated with COVID-19 vaccines are comparable to those of other vaccines. Vaccine. 2022; 40(2): 183-186.}