Coronavirus: Kiwi vaccinologist warns against jumping to conclusions over Pfizer vaccine warning

A top Kiwi vaccinologist says the public shouldn't jump to conclusions after the UK's medical regulator advised those with significant allergies not to get the Pfizer COVID-19 vaccine. 

Britain's Medicines and Healthcare products Regulatory Agency (MHRA) on Thursday issued advice on a "precautionary basis" that people with severe allergies don't get the Pfizer-BioNTech vaccine. 

"Any person with a history of a significant allergic reaction to a vaccine, medicine or food (such as previous history of anaphylactoid reaction or those who have been advised to carry an adrenaline autoinjector) should not receive the Pfizer BioNtech vaccine," it said.

It comes after the UK this week began a mass campaign of vaccinations against COVID-19 and two people with a history of allergies had an anaphylactic reaction to the shot. Both of them are recovering.

With COVID-19 vaccines being in hot demand and a vital tool in tackling the global pandemic, concern quickly arose about the safety of the jab and that people may be put off. 

However, vaccinologist and University of Auckland associate professor Dr Helen Petousis-Harris told Newshub everyone should take a big breath.

"Vaccines do have a rare potential for this, but we are talking about one-in-a-million generally. Knowing what is in the vaccine it seems quite unlikely to be given a greater risk than another vaccine to do this," she said.

Dr Petousis-Harris said that such incidents can occur when a mass campaign begins, mentioning that New Zealand has had issues with fainting.

"We have had experiences here where we have had people fainting and it being thought to be an anaphylactic reaction because they can present in a similar way. So I think we need to be really careful when these things happen that they are investigated properly and that we have good data on them."

MHRA chief executive June Raine is reported by Reuters as saying that during clinical trials of the vaccine an anaphylactic reaction wasn't "a feature". Pfizer also said that people with a history of severe adverse allergic reactions to vaccines are excluded from their late stage trials.

Dr Petousis-Harris said we can expect to "see all sorts of things like this start appearing in the news". 

"We are going to have to be really careful to allow them to be assessed and conclusions drawn without everyone jumping to conclusions right away and it's going to happen a lot.

"Most of them are not actually things caused by the vaccines. You need to step back and do the investigations to be sure."

The vaccine developers say they are working to understand the adverse reactions and their causes.