Allergic reactions spark Covid-19 vaccine warning

Britain’s medicines regulator has advised people with a history of significant allergies not to get the Pfizer-BioNTech Covid-19 vaccine after two people reported adverse reactions on the first day of its rollout in the UK.

UK officials said there had been two reports of anaphylaxis and one report of a possible allergic reaction since the rollout began on Tuesday.

Anaphylaxis can cause throat swelling, breathing trouble and difficulty swallowing, according to the American Academy of Allergy, Asthma & Immunology.

Anaphylaxis is an overreaction of the body’s immune system, which the UK National Health Service describes as severe and sometimes life-threatening.

British regulators initially responded by saying anyone with a history of a significant allergic reaction to a vaccine, medicine or food should not take the shot.

An adviser to the group later said it was “tweaking” advice in part to say a food allergy was not a risk.

Late on Wednesday, the UK regulator said anyone with a history of anaphylaxis to a vaccine, medicine or food should not get the vaccine.

Pfizer had excluded people with a history of significant adverse reaction to vaccines or its vaccine’s ingredients from late-stage trials.

US regulators are expected to consider emergency authorisation of the Pfizer vaccine soon after a Thursday meeting of advisers.

Moncef Slaoui, who is spearheading the US government’s vaccine development efforts, said on Wednesday he expected the British allergic reactions would be considered in the US authorisation process and that people with known severe allergic reactions probably should not take the vaccine until more was understood.

Some doctors praised the UK regulators’ caution, while others said broad restrictions were not warranted by available evidence.

“For the general population, this does not mean that they would need to be anxious about receiving the vaccination,” London School of Hygiene & Tropical Medicine pharmacoepidemiology professor Stephen Evans said.

What would be wise, he said, would be “for anyone who has known severe allergic reaction such that they need to carry an EpiPen to delay having a vaccination until the reason for the allergic reaction has been clarified”.

Mayo Clinic virologist Gregory Poland, who has advised US regulators, described Britain’s early reaction as “overdoing it”, pointing to the initial response about food allergies, which he said had nothing to do with the reactions.

“I would have said, ‘If you’ve had anaphylactic-level reactions to vaccines, we want to know about that so we take extra care’," he said.

“That doesn’t mean I wouldn’t immunise you.

“But I would do it in a more controlled setting.”

Imperial College London professor of experimental medicine Peter Openshaw praised the way the reactions had been handled.

“The fact that we know so soon about these two allergic reactions and that the regulator has acted on this to issue precautionary advice shows that the monitoring system is working well,” he said.

Director of the division of allergy and immunology at Nationwide Children’s Hospital in Ohio, Mitchell Grayson, voiced concern over how the issue might reduce interest in vaccinations.

“I’m worried the whole event will cause millions of people to choose not to get vaccinated because of what they heard,” he said.

Queen Mary University of London immunology expert Louisa James said: “In the UK in 2012 there were around seven hospital admissions per 100,000 people for severe allergies.

“This included different triggers such as foods, drugs and insect stings.”

James said fatalities remained  rare and had not increased even as hospital admissions had risen in many countries. — Reuters