ABSTRACT
Background: In December 2020, the vaccination campaign against COVID-19 virus started around the world. The Israel Ministry of Health decided to use vaccines for COVID-19 from Pfizer/Biontech. Early studies with Pfizer COVID-19 vaccines reported that there was a risk of allergic reactions in Britan and several in USA. The patients who had allergic reactions to the vaccine reported prior history of various allergies. Due to these reports Israel Ministry of Health issued warnings cautioning patients with allergies regarding receiving the vaccine. The leading hypothesis was that one of the components of the vaccine, PEG or polyethylene glycol, was the cause of allergic reactions. This substance if found in many other medications.Following these developments, there was a flood of inquiries from the allergic patients in Israel Method: We established a call center in Sheba Medical Center that provided preliminary screening for inquiries from the public. The patients were divided into 3 groups: 1. Patients at low/medium risk level -These patients were vaccinated in the local clinics. Example of patients in this category included patients with allergic rhinitis, well controlled asthma, food allergies, insect venom allergy and mild drug allergy;2. Patients at high risk -These were the patients with more serious drug allergies, not related to PEG. These patients received COVID-19 vaccination under supervision at the Sheba Medical Center;3. Patients at very high risk -These patients had anaphylaxis or severe allergic reactions to IV medications, prior vaccines or PEG. They had a full evaluation at our allergy department including a thorough history and physical and specific allergy testing for PEG and Pfizer COVID-19 vaccine. Result(s): There were 810 patients over the age of 16, who were in high-risk group, and received vaccination in the hospital under supervision of a medical team including allergy physicians and nurses. 217 of these patients were categorized as very high risk and had a full allergy evaluation prior to the vaccination. Out of the patients in the very high risk group, only 5/217 (2.3%) were found to be allergic due to positive skin tests to the vaccine or one of its components. Of all the high risk patients 794/810 (98%) were vaccinated with no immediate response to the vaccine. The 16 patients (2%) had immediate allergic reactions and out of this group 6 (0.7% of total) had an anaphylactic reaction. Conclusion(s): This project describes how an effective algorithm can be established to deal with an urgent need to vaccinate majority of the population.Our data show that the risk of allergic reactions to the Pfizer COVID-19 vaccine is small even within allergic population and that most of the patients can receive the vaccine safely.