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Allergic Reactions to COVID-19 Vaccine

Written By: Kaylee Zhou

The pharmaceutical companies, Pfizer and BioNTech, have partnered together and are officially starting to roll out their FDA-approved COVID vaccine. Pfizer launched the start of their Phase III clinical trial in July 2020, which had around 37,000 participating members. On November 18, 2020, the company reported that its vaccine had a 95% effectiveness rate (Grey, 2020). National Healthcare Administrations and Officials have praised both the companies and their vaccine by recognizing its potential towards the current pandemic crisis. 

During the clinical trials, there were no serious adverse events or side effects that were reported. However, common side effects involving vaccines and medications are inevitable. In this case, participants experienced reactions such as aches, fevers, chills, and headaches (CDC, 2020). Despite these common reactions, scientists were thrilled that the vaccine was successful regardless of a participant’s age, weight, and race (Weiland et al., 2020). 


The United Kingdom

The United Kingdom was the first country to approve the Pfizer vaccine on December 2, 2020, and they started their rollout to doctors, nurses, and medical staff on December 8. On December 9, two medical staff members reported symptoms of an anaphylactic reaction after receiving the vaccine a day before (Reynolds et al., 2020). An anaphylactic reaction occurs when the immune system mistakes a substance in one’s body as harmful and then releases chemicals that can cause allergic reactions. During the chemical release, the body can go into shock, which can be life-threatening since it causes drops in blood pressure, narrows airways, and results in difficulty breathing (Laguipo, 2019). It was also stated that the two staff members both had a history of severe allergic reactions and carried an adrenaline auto-injector with them (Reynolds et al., 2020). Due to these events and findings, the UK health officials released an announcement the following day stating that those with a history of severe allergic reactions to food and medicine or who suffer from anaphylaxis should avoid taking the vaccine (Kennedy, 2020). 


The United States

A little over a week after the United Kingdom, the United States approved the Pfizer vaccine on December 10 and started the official rollout on December 14. The United States Food and Drug Administration is now looking into five reported allergic reactions towards the vaccine. Dr. Peter Marks, the director of the FDA’s Center for Biologics Evaluation and Research, announced that the reports came from more than one state, and two of the five came from Alaska (Erman, 2020).  The two health workers from Alaska happened to work at the same hospital, and both experienced reactions approximately ten minutes after their injection. The first worker was a middle-aged woman who did not have a history of severe allergic reactions. She suffered from an anaphylactic reaction and exhibited symptoms, including a rash across her torso and face, shortness of breath, and an increasingly elevated heart rate. She was taken to an intensive care unit, where she was treated and discharged the following day. The second worker received his injection a day after the first woman; however, his symptoms were contrasting. His reaction was not considered anaphylaxis, but he suffered from lightheadedness, eye puffiness, and a scratchy throat. Luckily, he was able to be observed and released after an hour of treatment (Weiland, 2020). As a precaution, the FDA now requires appropriate medical treatment to be available where injections occur in case of anaphylactic reactions (Kennedy, 2020). 



Although there have been more reported reactions to the vaccine now than during clinical trials, this allows and assists scientists in learning more about human responses to ingredients in the vaccine. Similarly to the UK, the United States warns those who suffer from a history of severe allergic reactions to take precautions if and when taking the Pfizer vaccine. From the knowledge gathered during the clinical trials and the first phase of the mass rollout, the FDA plans to further research and consider allergies when approving future COVID-19 vaccines (Reynolds, 2020). While paying close attention to the responses this vaccine has caused, it is also important to acknowledge the successes it has brought, such as a possible opportunity for doctors and medical providers to stay safe while treating patients. 




References and Sources

Center for Disease Control and Prevention. (2020). What to Expect after Getting a COVID-19 Vaccine. Retrieved December 21, 2020, from

Erman, M. (2020, December 19). FDA investigating five allergic reactions after Pfizer shot in U.S. Retrieved December 21, 2020, from

Grey, H. (2020, December 16). What We Know About the Side Effects of Pfizer’s COVID-19 Vaccine. Retrieved December 21, 2020, from

Kennedy, D. (2020, December 19). FDA looking into allergic reactions reported after Pfizer COVID-19 shot. Retrieved December 21, 2020, from

Laguipo, A. (2019, February 27). What is an Adrenaline Auto Injector? Retrieved December 21, 2020, from

Reynolds, E., Braithwaite, S., & Cassidy, A. (2020, December 10). Allergy warning for Pfizer/BioNTech vaccine after UK health workers with allergy history suffer reaction. Retrieved December 21, 2020, from

Weiland, N., & Zimmer, C. (2020, December 08). Pfizer’s Vaccine Offers Strong Protection After First Dose. Retrieved December 21, 2020, from

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