LONDON—Two of the first people vaccinated in the U.K. on Tuesday with the Pfizer Inc. -BioNTech SE shot responded adversely to the injection, the country’s National Health Service said, prompting the regulator to issue new guidance warning those with a history of significant allergic reactions against having the inoculation.
“Both are recovering well,” said Professor Stephen Powis, national medical director for the NHS.
The two people are NHS workers, part of the first tranche to receive the vaccine in line with front-line staff having initial access. Each of them carried an adrenaline auto-injector to deal with their allergies.
The U.K. is the first Western country to authorize a Covid-19 vaccine and on Tuesday began its vaccination program with priority recipients including health-care staff, people over 80 years old and residents and staff in nursing homes.
The chief executive of the Medical and Health products Regulatory Agency, the body that last week gave the go-ahead for the Pfizer-BioNTech vaccination to be rolled out across the U.K., told lawmakers on Wednesday that on Tuesday evening it examined two cases of allergic reactions that hadn’t been a feature of the extensive clinical trials of the vaccine.
“Now that we’ve had this experience in the vulnerable populations—the groups who have been selected as a priority—we get that advice to the field immediately,” said Dr. June Raine.
The agency said that the vaccine, which is administered in two doses at least 21 days apart, had triggered an anaphylactoid reaction in the two people shortly after they received the shot. Such reactions are triggered sometimes by drugs such as aspirin, certain anti-inflammatory drugs and opiates.
“As is common with new vaccines, the MHRA have advised on a precautionary basis that people with a significant history of allergic reactions do not receive this vaccination,” Prof. Powis said.
The agency reminded health-care workers that vaccinations should only be carried out in facilities where resuscitation measures are available. It said it was seeking further information and would issue further advice following investigation.
Pfizer and BioNTech are supporting the MHRA in the investigation, Pfizer said.
“In the pivotal phase 3 clinical trial, this vaccine was generally well tolerated with no serious safety concerns reported by the independent Data Monitoring Committee. The trial has enrolled over 44,000 participants to date, over 42,000 of whom have received a second vaccination,” the company added.
BioNTech said that people with a history of severe allergic reactions to vaccines, medications or any component used in the trial were excluded from the process. The company advised that those with known allergies to vaccines should not receive the shot.
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