Addressing the Hesitancy: Looking at Allergic Reactions to COVID-19 Vaccines

Since the beginning of the COVID-19 pandemic, there have been over 29 million cases in the United States. The introduction of several effective vaccines has been a game changer in COVID-19 response. Currently, though, the challenge is along several fronts: vaccine hesitancy, equity, and the sheer logistics of vaccinating an entire country during a pandemic.

As of earlier this week, the United States had delivered over 135 million doses, administered over 107 million doses, and according to the US Centers for Disease Control and Prevention (CDC), 11.3% of the total population is fully vaccinated. Currently, 21% of the total U.S. population has received at least one dose and 35% of those 65 years or older have been fully vaccinated within the United States.

One of the hurdles in vaccinating an entire population is hesitancy and some of the most hard hit areas, like rural communities, are also areas where hesitancy can be prevalent and profoundly impacting. A KFF COVID-19 Vaccine Monitor study found that “rural residents are among the most vaccine hesitant groups, along with Republicans, individuals 30-49 years old, and Black adults. Individuals living in rural areas in the U.S. are significantly less likely to say they will get a COVID-19 vaccine that is deemed safe and available for free than individuals living in suburban and urban America. Three in ten (31%) people in rural areas say they will ‘definitely get’ the vaccine, compared to four in ten people in urban areas (42%) and suburban areas (43%). An additional one-third of people in rural areas say they will ‘probably get it’ while 35% say they will either ‘probably not get it’ (15%) or ‘definitely not get it’ (20%).”

There are many reasons for vaccine hesitancy and in the case of COVID-19, some include belief that the seriousness of virus has been exaggerated, the process was unsafely rushed, lack of concern for transmitting the virus, but also that there are adverse effects to getting vaccinated. This last concern is one in particular that a team of researchers sought to address in a new study.

In their publication within JAMA, they evaluated acute allergic reactions of mRNA COVID-19 vaccines by studying employees at Mass General Brigham who received their first dose of the vaccine, with a follow-up. Of the nearly 65,000 employees who received their first dose (of either Pfizer-BioNTech or Moderna), 81% completed at least one symptom survey.

The authors reported their findings from the survey. “Acute allergic reactions were reported by 1365 employees overall (2.10% [95% CI, 1.99%-2.22%]), more frequently with the Moderna vaccine compared with Pfizer-BioNTech (2.20% [95% CI, 2.06%-2.35%] vs 1.95% [95% CI, 1.79%-2.13%]; P = .03). Anaphylaxis was confirmed in 16 employees (0.025% [95% CI, 0.014%-0.040%]): 7 cases from the Pfizer-BioNTech vaccine (0.027% [95% CI, 0.011%-0.056%]) and 9 cases from the Moderna vaccine (0.023% [95% CI, 0.011%-0.044%]) (P = .76).”

Those individuals who experienced anaphylaxis had a mean age of 41 years and 94% were female, with 63% having a prior allergy history and 31% having an anaphylaxis history. The mean time to onset of anaphylaxis was 17 minutes, with one admitted to an intensive care unit and 56% receiving intramuscular epinephrine.

All who experienced anaphylaxis recovered and in fact, 3 did not seek care. The authors emphasized that 98% of those in their prospective cohort study did not have any symptoms of an allergic reaction after receiving their vaccine and that a majority of those who did, had a history of allergies.

Ultimately, this study demonstrates the very limited allergic reactions to COVID mRNA vaccines and while it would be beneficial to collect additional data after the second dose for many, this is helpful in aggressing the concerns about potential for reactions of these new vaccines.