UK issues Pfizer vaccine anaphylaxis warning after adverse reactions
By Alistair Smout
LONDON (Reuters) – Britain’s medicines regulator has said anyone with a history of drug or food anaphylaxis should not receive the Pfizer-BioNTech COVID-19 vaccine, giving more comprehensive guidance on a warning to previous allergy concerning shooting.
Starting with the elderly and frontline workers, Britain on Tuesday began mass immunizing its population, as part of a global campaign that poses one of the biggest logistical challenges in the history of the peace.
The Medicines and Health Products Regulatory Agency (MHRA) said there had been two reports of anaphylaxis and one report of a possible allergic reaction since the start of the deployment.
“Anyone with a history of anaphylaxis to any vaccine, drug or food should not receive the Pfizer BioNTech vaccine,” MHRA chief executive June Raine said in a statement.
“Most people will not get anaphylaxis and the benefits of protecting people from COVID-19 outweigh the risks … You can be completely confident that this vaccine has met rigorous safety standards, quality and efficiency of the MHRA.
Anaphylaxis is an overreaction of the body’s immune system, which the National Health Service describes as serious and sometimes fatal.
The more comprehensive guidelines, stating that the main risk was specifically from anaphylaxis, were released after consultation with allergy experts. The MHRA initially advised anyone with a history of a “significant allergic reaction” not to take the vaccine.
Pfizer and BioNTech have said they support the MHRA’s investigation.
Last week, Britain’s MHRA became the first in the world to approve the vaccine, developed by Germans BioNTech and Pfizer, while the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) continue to evaluate the data.
A senior U.S. official said on Wednesday that Americans with known severe allergic reactions may not be candidates for Pfizer’s COVID-19 vaccine until more is known about what happened.
Canada’s Department of Health said it would review the adverse reactions reported in Britain, but said adverse events were to be expected and would not necessarily change the risk / benefit of the vaccine, once the country has approved the vaccine.
MHRA chief Raine told lawmakers such allergic reactions had not been a feature of Pfizer’s clinical trials.
Pfizer said people with a history of serious adverse allergic reactions to the candidate’s vaccines or ingredients have been excluded from their late-stage trials, which is reflected in the MHRA’s emergency approval protocol.
However, the allergic reactions may have been caused by a component of Pfizer’s vaccine called polyethylene glycol, or PEG, which helps stabilize the injection and is not found in other types of vaccines.
Paul Turner of Imperial College London, an expert in allergy and immunology who advised the MHRA on its revised guidelines, told Reuters: “As we have had more information, the initial concern that this may affect being all allergic people is not true. “
“Ingredients like PEG which we believe could be responsible for the reactions are unrelated to things that can cause a food allergy. Likewise, people with allergies to a single drug shouldn’t be at risk,” said Turner to Reuters.
The EMA said in an email that all quality, safety and efficacy data will be considered in the evaluation of the vaccine, including data generated outside the EU.
In the United States, the FDA released documents Tuesday in preparation for an advisory committee meeting on Thursday, saying that Pfizer’s vaccine efficacy and safety data met its expectations for clearance.
The background documents indicate that 0.63% of people in the vaccinated group and 0.51% in the placebo group reported possible allergic reactions in trials, which, according to Peter Openshaw, professor of experimental medicine at Imperial College London, is a very small number.
“The fact that we knew about these two allergic reactions so early and that the regulator acted accordingly to issue precautionary advice shows that this monitoring system is working well,” he said.
However, Gregory Poland, a virologist and vaccine researcher at the Mayo Clinic in Rochester, Minnesota, said the MHRA and NHS overreacted initially.
“I wouldn’t have widened as much as they did,” he said.
“It’s reasonable to let the world know about this, and to be aware of it in terms of people who have had reactions like this to vaccines. the limits of science. “
(Reporting by Alistair Smout; additional reporting by Josephine Mason, Ludwig Burger, Francesco Guarascio and Julie Steenhuysen; Editing by Paul Sandle, Alexandra Hudson, Gareth Jones and Cynthia Osterman)