COVID-19 Vaccine and Allergic Reactions

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January 6, 2021

As COVID-19 vaccinations start, we hear a great deal in the press about allergic reactions. Serious reactions to the vaccine are very rare, despite what we hear in the news, but because this is all new, serious monitoring is being performed. It is necessary to remember that the risk of becoming gravely ill from COVID-19 is vastly higher than a serious adverse reaction to the vaccine.

Reactions to the COVID-19 vaccine can be divided into three main types: immediate allergic reactions, vasovagal reactions, and vaccine side effects.

Immediate allergic reactions (including anaphylaxis):

These usually occur within 15-30 minutes after vaccination and my include such symptoms as:
-feeling of impending doom
-feeling warm or cold
-fever, chills
-fatigue
-skin symptoms such as itching, hives, flushing, angioedema (swelling of lips, face or throat), pallor, sweating, clammy skin, or sensation of facial warmth
-neurologic symptoms such as confusion, disorientation, dizziness, lightheadedness, weakness or loss of consciousness
-respiratory symptoms such as shortness of breath, wheezing, stridor (high pitched sound with breathing), or low oxygen levels
-cardiovascular symptoms such as low blood pressure or rapid pulse
-gastrointestinal symptoms such as nausea, vomiting, abdominal cramps or diarrhea

Vasovagal symptoms

These usually occur within 15 minutes of vaccination. They include:
-feeling warm or cold
-skin symptoms such as pallor, sweating, clammy skin or sensation of facial warmth
-neurologic symptoms such as dizziness, lightheadedness, fainting, weakness, changes in vision (such as spots of flickering lights, tunnel vision), or changes in hearing
-respiratory symptoms such as rapid breathing may be present if there is anxiety
-sometimes nausea or vomiting

Vaccine side effects

These are similar to those from many other vaccines and may include pain, redness or swelling at the site of injection, fever, aches and pains, and fatigue. These usually resolve within 1-2 days and are very common.

People who get an anaphylactic reaction to a COVID vaccine should not get a second dose. People who have had an immediate reaction to other intramuscular, intravenous or subcutaneous medications or vaccines should discuss vaccination with their physician. Risks and benefits of COVID vaccination will need to be weighed. People who have had reactions to polyethylene glycol (PEG) or polysorbate should not get the vaccine without consulting with an allergist. Most people, however, will not know if they have an allergy to these compounds. 

People with a history of allergies to pets, foods, environment (like hayfever), latex, oral medications, eggs, venom/insect stings, or gelatin can safely get the COVID vaccine, as none of these are present in the vaccine. 

You can also get the vaccine if you have already had COVID-19, but should wait until 90 days after the infection. There is no increase in frequency of reactions in people who’ve had COVID. 

Anyone with a history of anaphylaxis to anything else (other than the above) can get the vaccine but should wait for 30 minutes after being vaccinated before leaving the clinical site. Everyone else should wait 15 minutes before leaving. Anyone with a history of vasovagal reactions or the common vaccine side effects can get the vaccine. Those with vasovagal reactions should probably lie down for their vaccination.

It is important that scientists and health authorities keep accurate accounts of side effects that people get to the vaccine. One very important way to do that is through “V-safe”. This is a self-referral site that provides personalized health check-ins after the COVID vaccine. It reminds you to get your second dose and offers you an opportunity to describe any reactions you may have, whether or not it’s clearly due to the vaccine. You need a smartphone to use this, and you can get it via www.cdc.gov/vsafe

The most important thing to know about this vaccine is that it’s safe and effective. Very few people need to avoid it for medical reasons. The only way to combat the pandemic is for 80% of the population to develop antibodies to the virus, know as herd immunity. However, after the vaccine, you may still get the virus: the vaccine reduces the likelihood of you getting very sick. That’s why we still need to wear face coverings and maintain social distancing. You can still infect another person. We do not yet know how much the vaccine limits transmissibility.  Until we have herd immunity, we will not get back to normal for a long time. So, please GET THE VACCINE! 

References: COVID-19 Vaccines: Update on Allergic Reactions, Contraindications, and Precautions. Webinar from CDC, December 30, 2020; and Interim Considerations: Preparing for the Potential Management of Anaphylaxis at COVID-19 Vaccination Sites, CDC

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