Covid-19 vaccines can cause strong allergic reactions in very rare cases.
However, rare or not, this is making many allergy sufferers around the world uneasy.
In Germany, allergy outpatient clinics are seeing an influx of people extremely worried about the vaccines, says Dr Ludger Klimek, president of the Medical Association of German Allergologists (AeDA).
”Many would like to be vaccinated and are looking forward to it, and then they read that a severe reaction is possible,” he remarks.
“This has raised a lot of uncertainty.”
So, how high exactly is the risk?
Since vaccinations started in England and the United States, there have been reports of some strong allergic reactions that occurred shortly after a vaccination and had to be treated.
Precise data on the frequency of such reactions after Covid-19 vaccinations aren’t currently available, however.
Based on existing preliminary data, Dr Klimek says, the new messenger ribonucleic acid (mRNA) vaccines by Pfizer/BioNTech and Moderna likely carry a somewhat higher risk than the other Covid-19 vaccines – around 2.5 to 4 times higher.
Nevertheless, he adds, the risk is still extremely low, namely “one case in every 100,000 vaccinations”.
Allergic reactions aren’t confined to Covid-19 vaccines, of course, but can occur after taking any medication.
No one becomes allergic to a substance by taking a Covid-19 vaccine, he says, explaining that an allergic reaction to an ingredient in the vaccine means you’ve already been previously sensitised to it.
As the injected dose of it is higher, the reaction can be stronger.
Also, not all allergy sufferers are affected equally.
“If you have hay fever, you’re not really at higher risk of side effects than someone without allergies,” says Dr Klimek.
But if you’ve ever had an allergic reaction to certain medications – a laxative or X-ray contrast agent, for example – you might also have one to the ingredients in the Covid-19 vaccines, he says, noting that known allergenic substances in medications include polyethylene glycol, polysorbate and ethylene oxide.
While completely eliminating a risk is hardly possible, Dr Klimek says, you’d do well to consult an allergist if you’ve had an allergic reaction to a medication.
If need be, the allergist can refer you to a specialised allergy centre that can make a specific recommendation based on your allergy and the ingredients in the various Covid-19 vaccines.
As for whether, say, the Pfizer/BioNTech vaccine would be a better choice than AstraZeneca/Oxford’s, or vice versa, he says: “(An assessment like) this is very complex and not affordable by every doctor’s surgery.”
In any event, health experts, such as those at Germany’s Federal Centre for Health Education (BZgA), have made it clear that if you know you’re allergic to an ingredient in a Covid-19 vaccine, you shouldn’t get that vaccine.
Before you’re vaccinated, it’s imperative that you accurately and thoroughly fill out your medical history questionnaire – and if in doubt, do so with the help of an allergist – so that personnel at the vaccination site know what to watch for and can further evaluate you if necessary.
After getting the jab, you have to remain on site for at least 15 minutes so that you can be monitored as a precaution.
The wait is 30 minutes if you’ve ever had an allergic reaction to a vaccine, the BZgA says.
The most serious kind of allergic reaction is anaphylaxis, in which your immune system releases a flood of chemicals that can cause you to go into shock.
“This is definitely life-threatening,” says Dr Klimek.
Less serious potential reactions include a skin rash, scratchy throat or itching.
According to the BZgA, vaccination sites and mobile vaccination teams are required to be equipped to treat any cases of anaphylaxis quickly. – By Tom Nebe/dpa
Information in this article was accurate at the time of its writing. Due to the fluid nature of the Covid-19 pandemic, scientific understanding, along with guidelines and recommendations, may have changed since the original publication date.