There are scattered media reports of extreme allergic reactions to Pfizer vaccine COVID-19. But, a thorough study shows that such cases are very rare. This only affects just 11 patients per million doses administered.
The CDC has found that episodes of extreme Allergic reactions to Pfizer Vaccine—called anaphylaxis—usually happened within minutes of receiving the shot. They were also rapidly resolved using epinephrine (such as the EpiPen).
Given the occurrence of Allergic reactions to Pfizer vaccines, the fact that we are in the middle of a pandemic and this vaccination is lifesaving still ensures a risk-benefit ratio on the vaccine side. It’s a lot.
Scientists at the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) reviewed the evidence of adverse reactions to the Pfizer-BioNTech vaccine in the United States shortly after the FDA approved its use December 11, 2020.
21 confirmed cases of anaphylaxis were reported between 14 and 23 December 2020.
About 1,893,360 individuals in the United States got their first dose of this vaccine over the same period. This is equal to 11.1 cases of anaphylaxis per million doses.
Out of the 21 people who had anaphylaxis, four needed hospitalization, and three needed intensive care. The emergency department carried out the treatment of the remaining 17 people.
When reporting to VAERS, 20 of the patients had either left or recovered from the hospital. There have been no reported deaths.
Of the 21 individuals, 17 (81 percent) had a documented history of allergies. And seven (33 percent) had anaphylaxis in the past.
Key Facts
- Researchers report a rate of 11.1 cases of anaphylaxis per million first doses of Pfizer-BioNTech COVID-19 vaccine.
- Anaphylaxis is a life-threatening allergic reaction that certain people experience after exposure to dangerous chemicals, such as a poison or a particular food or drug (including vaccines).
- Signs include trouble breathing and chewing, swelling of the face, and rapid heart rate.
Mild allergic reactions to Pfizer vaccine
The researchers noted 83 cases of milder Allergic reactions to Pfizer Vaccine. They did not meet the anaphylaxis requirements.
Symptoms of these reactions, commonly described, included:
- Pruritus (itchy skin)
- Rash
- An itchy and scratchy feeling in the throat
- Mild respiratory symptoms
Tom Shimabukuro of the CDC and Narayan Nair of the FDA reported their findings in the journal JAMA.
In their report, they highlight the advantages of vaccination against COVID-19:
The Pfizer vaccine is an mRNA vaccine. This includes genetic material that instructs the cells to make a harmless portion of the virus. This protein fragment cannot cause COVID-19. But it induces an immune reaction that protects against the disease.
The CDC has given general advice to health professionals on using mRNA COVID-19 vaccines. It also gave specific recommendations on treating anaphylaxis after vaccination with COVID-19. So, these guidelines require the screening of vaccine patients to identify anyone with contraindications to their ingredients.
The CDC also advises on the time of observation after administration. They prescribe 15 minutes for most patients but 30 minutes for someone who has a history of anaphylaxis.
What do we know about the anaphylaxis cases?
Of the 21 cases of extreme anaphylaxis associated with Pfizer-BioNTech, 19 were in women. Half were in individuals between the ages of 40 and 60. The other half are between 27 and 40 years of age. Seventeen of the cases were individuals with a history of allergic responses to:
- Food
- Medicines
- Other forms of vaccines
- Bee and wasp stings
Seven had a history of anaphylaxis in the past.
In 18 of the 21 reported cases, patients began to show signs of anaphylaxis within 30 minutes of receiving the dose. Almost all of them were treated urgently with epinephrine. It is a common anaphylaxis drug and the active ingredient in Epi-Pen. Only four people needed hospitalization. At least 20 of the 21 patients had completely recovered by December 23.
There is no geographic clustering of cases because they trace back to different lots of the vaccine. So, there is no evidence that the toxicity of the vaccine was a matter of concern. Case data is still early. The skew towards women may indicate a genuine biological phenomenon. It may represent that more women than men—62% of the 1.89 million—received the vaccine throughout the study period.
Is there a clear difference in risk between Pfizer-BioNTech and Moderna vaccines?
Right now, no. Raw totals resulted in more cases from the Pfizer-BioNTech vaccine than the Moderna vaccine. However, CDC officials believe this is likely because the Pfizer-BioNTech version was first approved. And more people received it during the study period.
Authority administrated 1,893,360 doses of Pfizer-BioNTech vaccine during the study period. This is nearly 8.5 times the 224,322 Moderna doses administered during the same period. Moreover, the rollout of Moderna’s vaccine did not start until the last three days of the study period, on December 21. Of such doses of Moderna, just one case of anaphylaxis has been reported to the CDC.
Should I get the vaccine?
In the meeting, Messonnier and Tom Clark, head of the CDC Vaccine Assessment Committee, stressed that, in general, people should get it.
Authority should observe individuals for 15 minutes after receiving the vaccine. Then they can ensure rapid response to the Pfizer vaccine’s unusual allergic reactions. They should monitor people with a history of anaphylaxis or immediate Allergic reactions to Pfizer Vaccine for 30 minutes.
Clark told who should not get a full two-dose Pfizer-BioNTech vaccine regimen. He stated, “If you have an immediate response to the first [COVID-19] dose, do not take a second. And if you have a reported allergy to components of the vaccine, it is advised that you should not get vaccinated at this time.” Are you unsure if you might be allergic to the vaccine ingredient? Then you should talk to your doctor before vaccination.
Epinephrine injections
In possible anaphylaxis cases, the CDC states that healthcare professionals should give an immediate shot of epinephrine.
Epinephrine, also known as adrenaline, is a hormone that counteracts the symptoms of anaphylaxis. People who have experienced such a response in the past should also carry a self-injector.
The Bottom Line
In response to Allergic reactions to Pfizer Vaccine, the CDC published updated recommendations on December 19. People who have serious allergic reactions to the Pfizer COVID-19 vaccine’s first dose should not receive the second dose. The Department also recommends people who have experienced serious allergic reactions to other vaccines contact a doctor before receiving the vaccine.
