Severe allergic reactions to the COVID-19 vaccine made by Pfizer and BioNTech were “rare” in the first ten days of its spread across the country, according to a new report from the Centers for Disease Control & Prevention.
A total of 21 cases of anaphylaxis, none of which were fatal, were confirmed among nearly 1.9 million doses administered, CDC researchers wrote in the weekly report on morbidity and mortality on Wednesday. This equates to 11.1 cases per 1 million doses.
Anaphylaxis is a severe allergic reaction that can be caused by a vaccine, as well as by food, medication, insect stings and latex. The reaction can be fatal if not treated immediately, usually with an injection of epinephrine into the airways in the lungs.
The reports of anaphylaxis and other side effects of the Pfizer-BioNTech vaccine have been submitted to the Vaccine Adverse Event Reporting System (VAERS), which is maintained by the CDC and the Food and Drug Administration to keep up with safety issues once a vaccine was made. available to the public.
Pfizer-BioNTech’s COVID-19 vaccine was the first to receive authorization for emergency use from U.S. regulators, and the first doses arrived in the arms of health care workers on Dec. 14. The new CDC report is based on 1,893,360 doses administered until December 23rd.
These doses resulted in 175 possible cases of severe allergic reactions. Investigators who reviewed the cases determined that 21 of them were anaphylaxis, and 86 other allergic reactions. Sixty-one cases were not allergic reactions at all, and seven are still being investigated.
Among the 21 people who had anaphylaxis, 17 had allergies, including seven people who had already had anaphylactic reactions.
Seventeen of the 21 patients were treated in emergencies and four patients were admitted to the hospital. Three of the patients admitted to the hospital required intensive care.
Twenty of the patients recovered when their cases were reported to the vaccination system. Details about the 21st patient were not known, but the CDC researchers noted that there were no reports of deaths related to anaphylaxis related to the Pfizer-BioNTech vaccine.
The 21 patients were between 27 and 60 years old, with an average age of 40. Nineteen of them – or 90% – were women. The authors of the report noted that among the cases where the gender of a vaccine recipient was known, 64% were women. They also pointed out that women are more likely to have an “immediate hypersensitivity” to the H1N1 flu vaccine during the 2009 flu pandemic.
After receiving the COVID-19 vaccine, the fastest anaphylactic reaction occurred after only two minutes, and the slowest appeared after 150 minutes. The vast majority of reactions came quickly, with 15 occurring within the first 15 minutes of injection, and another three between 15 and 30 minutes.
Nineteen of the patients were treated with epinephrine.
The 21 cases were not pooled in a single geographic area, and they were linked to doses from different parts of the vaccine.
Among the other cases of allergic reactions, more than four out of five were considered ‘nonsensical’. The most common reactions reported with VAERS were skin rash or itchy skin, an itchy or itchy throat and mild breathing symptoms. Half of these reactions occurred within 12 minutes of receiving the vaccine, and 90% of those who suffered from it were women.
Overall, VAERS received 4,393 reports of adverse events of any kind during the first ten days of the Pfizer-BioNTech vaccination, according to the report. This is a rate of 0.2%.
The CDC has already updated its guidelines for administering the vaccine and a similar one developed by Moderna and the National Institutes of Health, which received authorization for emergency use a week after the Pfizer-BioNTech product. This guide includes:
• Make sure epinephrine is on hand and ready to use on vaccination sites.
• Ask potential vaccine recipients about their history of allergic reactions to identify those at high risk.
• Keep people under observation for up to 30 minutes after receiving the vaccination so that cases of anaphylaxis can be treated quickly.
• Make sure healthcare providers who give the vaccine are trained to recognize the early signs of anaphylaxis.
• Immediately give an intramuscular injection of epinephrine if anaphylaxis is suspected.
The first doses of the Moderna vaccine were administered on December 21, and less than 225,000 doses were dispensed during the ten-day period of this study. A separate report on the side effects is in the works, CDC researchers said.