Two of the first people to be given the Pfizer vaccine had a reaction and are recovering. These two individuals are health care providers. Both carried epinephrine injectors for allergies.
The reactions were 'anaphylactoid' - a type of adverse reaction that is triggered by medications such as aspirin, non-steroidal anti-inflammatory agents (NSAIDs), and opiates.
In the U.K. the Medical and Health Products Regulatory Agency (MHRA) has advised, as a precaution, that people with a significant history or allergic reactions do not receive this vaccination. There was also the recommendation that the vaccination only be done in a facility that is equipped with resuscitation equipment.
A few points to ponder;
- We do not know what these 'severe allergies' were.
- Having epinephrine does not ALWAYS mean severe allergy- for the most part it does, but sometimes it is given for other reasons.
- The reactions were labeled anaphylactoid - that means anaphylaxis like, but no ability to detect an allergy antibody (IgE) to the product.
- There were 44,000 participants in the vaccine trial - what was the severe allergy story in that group?
- This is a very different type of vaccine - a messenger RNA vaccine and not the usual protein-type vaccine. Most of us have never had a vaccine of this type.
Going forward, we will keep you posted as to what was going on and if there are clues from these two individuals that can help us understand who may be at risk. What are the specific risk factors?We will need to define what a severe allergy is for our patients. There are a number of severity scores for asthma, allergic rhinitis, and atopic dermatitis- that gives the severity of the clinical condition. We have those who have anaphylaxis which is the most severe presentation of allergy. Within the world of anaphylaxis there are so many different triggers - for me, I had anaphylaxis from testing- a severe reaction, but I do not carry epinephrine because I am not allergy tested everyday.
Many patients have been told that they have severe allergies for a variety of reasons. We will need to dispel myths about severity - for example the size of an allergy skin test and/or the value on a blood test does not necessarily correlate with severity. I frequently equate severity to what happens in the field to the individual with the exposure.
Severity can vary with health status, amount of exposure, and concomitant medications- a few variables.
We will also need to sort out how can we protect with the COVID vaccine in someone who is at risk. Allergy affects up to 30% of the population. For a successful vaccine program to control a public health hazard, you can't have 30% of the population not vaccinated.
I hope we can get some answers soon.
Frederick E. Leickly, MD,MPH