2% reported mild reactions after Pfizer, Moderna jabs in US

Around 2 per cent of people who received the first dose of Pfizer-BioNTech and Moderna’s mRNA-based Covid-19 vaccines reported allergic reaction, finds a US-based study.

The study indicated that among those who were surveyed after they received their first dose of mRNA Covid-19 vaccine, 2 per cent experienced allergic reactions and anaphylaxis occurred at a rate of 2.47 per 10,000 individuals.

“The Covid-19 mRNA vaccines are the first vaccines of their kind, and they have remarkable efficacy and safety across all populations,” said lead author Kimberly Blumenthal from the Massachusetts General Hospital in the US.

“It is critical to have accurate information on allergic reactions to these vaccines, not only for our current situation, but also because this new vaccine platform is so important for future pandemic responses,” Blumenthal added.

For the study, published in the Journal of the American Medical Association (JAMA), the team surveyed 52,805 employees (including an estimated 4,000 with significant allergies to foods and medications).

The team carefully documented all allergic reactions, including anaphylaxis, once they began employee vaccinations at Mass General Brigham.

The team analyzed employee surveys to estimate the incidence of allergic reactions after mRNA vaccines and used multiple surveillance methods to identify the true incidence of anaphylaxis.

The investigators noted that although the incidence of anaphylaxis was higher than that estimated by the Centers for Disease Control and Prevention — which put the rate at 0.025 to 0.11 per 10,000 vaccinations — it is still exceedingly low and should provide reassurance, especially for individuals with a history of food or drug allergies.