This large, prospective study involved the Pfizer-BioNTech COVID-19 vaccine, one of three COVID-19 vaccines currently in use in the United States.
“We assume that these lessons will be generalizable to the Moderna and other mRNA vaccines with similar excipients and constructs,” Dr. Elizabeth J. Phillips, a professor in the department of medicine at Vanderbilt University Medical Center in Tennessee, said in an editorialTrusted Source that accompanied the study.
About The Study
The researchers gathered data from December 27, 2020 to February 22, 2021 at Sheba Medical Center in Israel.
More than 8,000 people with allergies went through risk assessment using an algorithm that included a detailed questionnaire.
Slightly more than 400 participants were defined as “highly allergic.” Of those, 71 percent were women.
This group received the vaccine under medical supervision. Following the first dose:
Almost 98 percent of participants had no allergic reaction.
Slightly more than 1 percent of participants developed a mild allergic response, such as skin eruptions, flushing, swelling of the tongue or uvula, or cough.
Less than 1 percent of participants had an anaphylactic reaction, a potentially life-threatening condition.
Anaphylactic reactions appeared within 10 to 20 minutes after vaccination. Treatment included adrenaline, antihistamines, and an inhaled bronchodilator. Symptoms resolved within 2 to 6 hours. None of the participants needed hospitalization.
The participants who had an anaphylactic reaction didn’t get a second dose in this study period.
Slightly more than half the group got their second dose during the study period. After the second dose, 98 percent of participants had no allergic reaction, while almost 2 percent experienced a mild reaction.
Study authors concluded that the rate of allergic reactions to the Pfizer-BioNTech COVID-19 vaccine is higher than for other commonly used vaccines, especially in people with a history of allergic reactions.
However, most people with a history of allergies can be safely immunized with use of an algorithm that includes risk assessment and medical supervision for those who are highly allergic.
The researchers acknowledge the need for more studies to define the exact risk factors for anaphylaxis among highly allergic people.
One of the researchers, Dr. Gili Regev-Yochay, disclosed receiving personal fees from Teva and grants from Pfizer outside the submitted work.
Dr. Jan K. Carney is the associate dean for public health and health policy and a professor of medicine at Larner College of Medicine at the University of Vermont.
Carney told Healthline the research was well-conducted.
“The study helps us identify (screen) patients for an especially high risk of severe allergy against COVID-19 and determine safe and practical vaccination approaches against this deadly virus,” she said.