British health officials have warned that people with a history of “significant” allergic reactions to vaccines, medicines or food should not be given the Pfizer COVID-19 vaccine. Two people in the UK’s first group of COVID-19 vaccines, both health workers, experienced “adverse reactions” after taking it.
To date, only three cases of allergic reactions have been reported in the United States. A couple of health workers at an Alaska hospital experienced allergic reactions after getting the vaccine. One worker, who had no history of allergies, had a severe reaction, known as anaphylaxis, while the second suffered a less severe allergic reaction.
A second severe reaction was reported to a separate hospital in Alaska later this week. All three were treated and recovered quickly.
The Centers for Disease Control and Prevention and Recommendations recommend that people with “a history of severe allergic reactions, such as anaphylaxis to any vaccine or any injectable therapy,” should take “caution,” but should not avoid the one at all.
This guide is based on Pfizer’s clinical trials, in which about 22,000 people received the vaccine and far less than 1% had possible allergic reactions. “Among a subset of participants in phase 2/3 clinical trials, 0.63% of participants in the vaccinated group had hypersensitivity-related adverse events, possibly representing allergic reactions (compared with 0.51 % of the placebo group), ”says the CDC Interim Clinical Considerations on Pfizer Vaccine Use.
During the trials, “there were no cases of anaphylaxis,” Pfizer said. “Overall, no safety signs of concern were identified in our clinical trials, including any signs of serious allergic reactions associated with the vaccine,” a Pfizer spokesman told CBS News. “However, reports of adverse events outside of clinical trials are a very important component of our pharmacovigilance activities and we will review all available information on this case and all reports of adverse events after vaccination.”
“We do not yet have all the details of the Alaska report on a possible severe allergic reaction, but we are actively working with local health authorities to assess,” the spokesman said. “We will closely monitor all reports suggesting severe allergic reactions after vaccination and will update the labeling language if necessary.”
People who wanted to participate in the Pfizer phase 3 trial “were excluded if they had a history of a serious adverse reaction associated with a vaccine and / or a severe allergic reaction (eg, anaphylaxis) to any component of the research vaccine.” , according to the company. . Therefore, it is true that people with a history of severe allergic reactions get the vaccine for the first time when it is released to the public.
Dr. Mark Dykewicz, an allergy and immunology expert at St. Paul University Hospital. Louis and a member of the Food and Drug Administration’s Allergic Advisory Committee said he has been asking about the vaccine from patients with an anaphylactic history.
“I’m telling my patients that they should go ahead and get it,” he said.
According to Dykewicz, the risk is reduced by the presence of medical personnel at the time of injection, when the reaction is most frequent. CDC guidelines require vaccine providers to observe “patients with a history of anaphylaxis (for any reason) for 30 minutes after vaccination … to monitor for the presence of immediate adverse reactions” and to observe “all other people “. “for 15 minutes after vaccination”.
Dykewicz stressed that the advantage of protecting against COVID-19 outweighs the risk of a possibility of one billion serious allergic reactions to the vaccine. “By balancing the pros and cons of this, I would recommend that they achieve this,” he said.
“In general, the overall risk of anaphylaxis for vaccines (of all types) is approximately 1 [in] 1,000,000, “according to Dr. David Peden, an expert in allergy and pediatric immunology at the University of North Carolina at Chapel Hill Medical School and chair of the allergen products advisory committee.” That happens, but it’s extremely rare, ”he said.
Since allergic reactions to the Pfizer vaccine have not yet been formally studied, it is not yet known which component or components of the drug may cause a reaction. “It is not clear which element of the vaccine is responsible for the small amount of allergic emergencies associated with the vaccine,” Peden said.
According to Dykewicz, the Pfizer vaccine does not contain any of the “usual suspects,” such as gelatin, which is known to cause a reaction.
The part of a vaccine that attacks a virus: messenger RNA, in the case of Pfizer and Moderna, is just one component; they also contain small amounts of other ingredients, known as excipients. “Stabilizers,” usually sugars or gelatin, are excipients that help keep the vaccine potent during transport and storage, according to the CDC. The Pfizer vaccine, which is kept at 94 degrees below zero Fahrenheit to maintain effectiveness, does not contain gelatin. It also contains no preservatives.
“Most allergic / immunological doctors are more concerned about additives to stabilize the vaccine, rather than the actual vaccine antigen,” Peden said.
It is too early to know if any similar case can occur Modern vaccine, which the FDA authorized Friday. A representative of Moderna told members of the FDA Vaccine Advisory Panel that there was a report of anaphylaxis during the trials, but it occurred more than two months after vaccination and therefore was probably unrelated to the vaccine, STAT reports. Moderna’s chief medical officer also noted during the meeting that the lipid nanoparticles in the vaccine (small spheres of fatty material used to administer the mRNA) used in the vaccine are not the same lipid nanoparticles as Pfizer.
Dykewicz, however, said that without knowing which component of the Pfizer vaccine caused the reactions, it is impossible to know if Moderna’s vaccine has it in common. “The bottom line is that at this time we don’t know what component or components are leading to an allergic reaction,” he said.
Resetting the culprit will take a while, a time that will also help determine the frequency of these reactions in the general population. Dr. Amal Assa’ad, associate director of the Allergy and Immunology Division at Cincinnati Children’s Hospital and a member of the advisory committee, said that without a “denominator” it will be difficult to know if reactions occur in the · allergic to the expected rhythm.
And people who have never had allergic reactions may be at risk for a new substance, including vaccines. However, experts stress that the risk is very small and that even those with a history of allergic reactions should be immunized.
“The risk, while not nil, is extremely small and people without a history of vaccine anaphylaxis should not avoid vaccination on that basis,” Peden said. “… In general, even with a history of allergy (except for a specific history of anaphylactic reaction to another vaccine), people should be vaccinated against COVID-19, especially if they are in a high risk group “.