British health officials have warned that people with a history of “significant” allergic reactions to vaccines, medicines or food should not be given the COfID-19 Pfizer vaccine. Two people in the first group of COVID-19 vaccines in the UK, both health workers, experienced “side effects” after administration.
To date, only three cases of allergic reactions have been reported in the United States. A couple of medical workers at an Alaska hospital had allergic reactions after receiving 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 the second serious 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 recommends that people with a “history of severe allergic reactions, such as anaphylaxis to any vaccine or any injection therapy” take “precautions”, but should not avoid the vaccine altogether.
These guidelines are based on Pfizer clinical trials, in which approximately 22,000 people received the vaccine and less than 1% had possible allergic reactions to it. “Among a subgroup 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 to 0.51% in the placebo group).” shows in the CDC Interim Clinical considerations regarding the use of the Pfizer vaccine.
During the studies, “there were no cases of anaphylaxis,” Pfizer said. “In general, no safety signs have been identified that are of concern in our clinical trials, including any signs of severe allergic reactions associated with the vaccine,” a Pfizer spokesman told CBS News. However, adverse event reports outside of clinical trials are a very important component of our pharmacovigilance activities and we will analyze all available information about this case and all adverse event reports after vaccination.
“We do not yet have all the details of the Alaska report on a potential serious allergic reaction, but we are actively working with local health authorities to assess it,” the spokesman said. “We will closely monitor all reports suggesting severe allergic reactions after vaccination and update the labeling language if necessary.”
People who wanted to participate in the Pfizer Phase 3 study “were excluded if they had a history of severe vaccine-associated side effects and / or severe allergic reactions (eg, anaphylaxis) to any component of the investigational vaccine,” according to the company. . So, it is true that people with a history of severe allergic reactions will get the vaccine for the first time, as it is released to the public.
Dr. Mark Dykewicz, expert in allergies and immunology at St. John’s University Hospital. Louis, a member of the Food and Drug Administration’s Allergic Advisory Committee, said he had asked questions about the vaccine from patients with an anaphylactic history.
“I tell my patients that they should go ahead and get it,” he said.
According to Dykewicz, the risk is diminished by the presence of medical staff at the time of injection, when a reaction is most common. The CDC guidelines require vaccine providers to observe “patients with a history of anaphylaxis (for any reason) for 30 minutes after vaccination … to monitor for immediate adverse reactions” and to observe “all others”. “For 15 minutes after vaccination”.
Dykewicz pointed out that the advantage of protection against COVID-19 exceeds the risk of a 1 in 1 million severe allergic reaction to a vaccine. “Balancing the pros and cons of this, I would recommend getting them,” he said.
“In general, the overall risk of anaphylaxis for vaccines (of all types) is about 1 [in] 1,000,000, “according to Dr. David Peden, an expert in pediatric allergies and immunology at the University of North Carolina at Chapel Hill Medical School and chair of the allergen advisory committee.” It happens, but it is extremely rare, “he said.
Because allergic reactions to the Pfizer vaccine have not yet been formally studied, it is not yet known which component or components of the medicine may cause a reaction. “It is unclear which element of the vaccine is responsible for the small number of allergic emergencies associated with the vaccine,” Peden said.
According to Dykewicz, the Pfizer vaccine does not contain any of the “common suspicions”, such as gelatin, which is known to cause a reaction.
The part of a vaccine that attacks a virus – RNA messenger, 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 strong 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 does not contain preservatives.
“Most allergic / immunological doctors are most concerned about vaccine stabilization additives, rather than the actual vaccine antigen,” Peden said.
It is too early to know if similar cases may occur Modern vaccine, which the FDA approved on Friday. A representative for Moderna told members FDA Vaccine Advisory Committee that there was a report of anaphylaxis during the studies, but it appeared more than two months after vaccination and therefore was probably not related to the vaccine, reports STAT. The head of Dr. Moderna also mentioned during the hearing that the lipid nanoparticles of the vaccine – small spheres of fatty material used to provide mRNA – used in his vaccine are not the same lipid nanoparticles as Pfizer.
However, Dykewicz said that without knowing which component of the Pfizer vaccine caused the reactions, it is impossible to know if the Moderna vaccine has it in common. “The conclusion is that at this time we do not know which component or components are leading to an allergic reaction,” he said.
Reducing the culprit to zero will take time, which will also help determine how common such reactions are 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 would be difficult to say whether allergic reactions occur at the rate. anticipated.
And people who have never had an allergic reaction may still be at risk for one with any new substance, including vaccines. However, experts point out that the risk is very low and even those with a history of allergic reactions should be immunized.
“The risk, while not zero, is extremely low, and people without a history of vaccine anaphylaxis should not avoid vaccination on this basis,” Peden said. “… In general, even with a history of allergy (except for a specific history of anaphylactic reaction to another vaccine), people should proceed with COVID-19 immunization, especially if they are in a high-risk group. picked up.”