News of the Covid vaccine and allergy has many allergic patients concerned. It was reported in the United Kingdom that two NHS staff had severe anaphylactoid (anaphylaxis-like) reactions after receiving the vaccine. Both patients had a significant history of allergy and carried epinephrine autoinjectors. Anaphylaxis is the most severe form of an allergic reaction and has been associated in the past with other vaccines. However, it is not known if these reactions were a direct result of the vaccines. One possible culprit is polyethylene glycol, or PEG, which helps to stabilize the vaccine. This ingredient is not found in other types of vaccines. There has been no link to food allergy. Data from Pfizer’s trial is reassuring, only a small number (0.63%) of participants who received the vaccine reported possible allergic reactions (compared to 0.51% who received a placebo). For reference, the Pfizer Covid vaccine contains no preservatives (i.e. thimerosal), food allergen (i.e. egg) and the vial stoppers are not made with natural rubber latex.
All treatments are associated with risk. An individual decision would weigh the risk with the potential benefits, which in this case may be substantial. Patients who have a history of severe allergic reactions to vaccines, multiple medications or the additives and preservatives used in medications should consider consulting an allergist prior to receiving the Pfizer COVID vaccine.
As allergists, we know there is a rare risk of anaphylaxis to vaccines. In fact, patients with a history of anaphylaxis tend to have other associated allergic conditions (i.e. insect allergy, food allergy, atopic dermatitis, etc.) But patients with a history of food allergy or latex does not increase the risk of anaphylaxis to the vaccine. It is very important for patients to be speak to their doctor if they:
- have any allergies
- have a fever
- have a bleeding disorder or on a blood thinner
- are immune compromised
- are pregnant or plan to become pregnant
- are breast feeding
- have received another Covid vaccine
Currently, there are over 200 vaccines that are being tested against Coronavirus, the virus that causes COVID-2. These have been found to be highly efficacious in preventing symptoms in patients with COVID. Usually, a true allergic reaction does not occur after 2 hours of receiving the vaccines.
You should not get the Pfizer Covid-19 vaccine if you:
- had a severe allergic reaction after a previous dose of this vaccine
- had a severe allergic reaction to any ingredient in this vaccine
WHAT ARE THE INGREDIENTS IN THE PFIZER-BIONTECH COVID-19 VACCINE? The Pfizer BioNTech COVID-19 Vaccine includes the following ingredients: mRNA, lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-Distearoyl-sn-glycero-3- phosphocholine, and cholesterol), potassium chloride, monobasic potassium phosphate, sodium chloride, dibasic sodium phosphate dihydrate, and sucrose. (Taken from: The Pfizer-BioNTech COVID-19 Vaccine Fact Sheet)
The Pfizer-BioNTech COVID-19 vaccine is not a live vaccine and can be administered to immunocompromised patients. Physicians and other providers should inform such immunocompromised patients of the possibility of a diminished immune response to the vaccine.
In conclusion, the risk of the covid vaccine and allergy are very low. Patients who have history of any allergy (except for the ingredients in the vaccine) are not currently excluded from receiving the Pfizer Covid vaccine.
Individuals with common allergies to medications, foods, inhalants, insects and latex are no more likely than the general public to have an allergic reaction to the Pfizer-BioNTech COVID-19 vaccine. Those patients should be informed of the benefits of the vaccine versus its risks. Although the UK recommended anyone with anaphylaxis to a food, medication or vaccine to avoid it, these recommendations are not given in the US.
I would like to thank Dr. Phil Hemmers and Dr. Yudy Persaud for their contribution to this blog post.