High-Risk Allergy Associated with Allergic Reactions from COVID-19 Vaccine

Investigators noted that despite these self-reported allergic reactions, they were not an impediment for the completion of the 2-dose vaccination series.

A new cohort study found that self-reported history of high-risk allergy was associated with an increased risk of self-reported allergic reactions within 3 days of vaccination for the COVID-19 virus.

Despite this, reported allergy symptoms were not an impediment for the completion of the 2-dose vaccine protocol among a cohort of eligible health care employees, which supported the overall safety of the vaccine.

The cohort study, led by Rajesh I. Patel, MD, AtlantiCare Regional Medical Center, obtained demographic, medical, and vaccine administration data of employees of Mass general Brigham to assess the association between self-reported history of high-risk allergy and self-reported allergic reactions after mRNA COVID-19 vaccination.

The Methods

Home to 87,000 employees, Patel and colleagues only studied Mass General Brigham employees who received at least 1 dose of the COVID-19 vaccine and completed at least 1 post-vaccination symptom survey assessment.

A total of 52,998 health care employees were included, 51,706 of whom received 2 doses of the COVID-19 vaccine. A total of 474 employees reported a history of high-risk allergy.

The study period was from December 14, 2020, to February 1, 2021. A follow-up was conducted through March 1, 2021.

During the study, a pre-vaccination allergy risk assessment was performed through a screening questionnaire that employees completed either online, by telephone, or in person.

Employees were also directed to an existing COVID-19 symptom-check application to record any post-vaccination symptoms daily for 3 days after vaccination.

Additionally, exposure status was recorded before the initial administration from each employee’s completed questionnaire.

The primary outcome of the study was 1 or more self-reported allergy symptoms in the first 3 days after either dose 1 or dose 2 of the vaccine. The secondary outcome was self-reported severe allergy symptoms to the vaccine, which included hives, itching, rash, respiratory symptoms, angioedema, or both.

The Findings

Investigators reported that 97.6% of the cohort had successfully completed the recommended 2-dose COVID-19 vaccine series.

A total of 2516 employees (4.7%) reported 1 or more allergy symptoms in the 3 days after receiving either dose of the vaccine. Individuals with a history of high-risk allergy reported more allergic reactions than those without (11.6% vs. 4.7%, respectively).

Mild symptoms such as rash or itching were among the most commonly reported reactions in the cohort, followed by respiratory symptoms, hives, and angioedema.

The relative associations of high-risk allergy with risk of allergic reactions were consistent across all other strata of risk factors, and self-reported severe allergic reactions in the days after vaccination were uncommon.

In an adjusted model, a history of high-risk allergy was associated with an increased risk of allergic reactions (adjusted relative risk [aRR], 2.46; 95% CI, 1.92-3.16), with risk being highest for hives (aRR, 3.81; 95% CI, 2.33-6.22) and angioedema (aRR, 4.36; 95% CI, 2.52-7.54).

In their conclusion, Raji and colleagues proposed future studies with diverse populations be conducted to address ongoing questions regarding the safety of the COVID-19 vaccine. They believed studies could be used to better understand risk factors including sex for allergic reactions after vaccination.

Despite this, they were confident in their findings.

“This study not only highlighted that high-risk allergy history was associated with allergy symptoms after COVID-19 vaccination but also supported the overall safety of mRNA vaccines in all eligible individuals,” the team wrote.

The study, “Association of Self-reported High-Risk Allergy History With Allergy Symptoms After COVID-19 Vaccination,” was published online in JAMA Open Network,