Vaccines can sometimes cause allergic reactions, but they are usually rare and short-lived. British regulators are investigating reports of allergic reactions in two people who received the new Pfizer COVID-19 vaccine on Tuesday, the first day of a vaccination program. Meanwhile, they are telling people to skip the vaccine if they have had a history of severe allergic reactions. A look at allergic reactions to vaccines:
HOW OFTEN DO THEY OCCUR?
Allergic reactions can occur with numerous vaccines, and experts say they are not unexpected. In the Pfizer-BioNTech study of 42,000 people, the rate was roughly the same in those who received the coronavirus vaccine compared to those who received a sham injection. Reviewers from the US Food and Drug Administration who examined the study’s safety data found that 137 (or 0.63%) of vaccine recipients reported symptoms suggesting an allergic reaction, compared with 111 (or 0.51%) in the placebo group.
A 2015 study in the US that examined the rate of anaphylaxis, a serious life-threatening allergic reaction, found that it occurs approximately once per million doses of vaccine. The study evaluated children and adults who received vaccinations against numerous diseases, including polio, measles and meningitis. “For the general population, this does not mean they should be eager to get the vaccine,” said Stephen Evans, a vaccine expert at the London School of Hygiene and Tropical Medicine. He noted that even common foods can cause severe allergic reactions.
WHY DO THESE REACTIONS HAPPEN?
Scientists say that people may be sensitive to ingredients in the shot, such as gelatin or egg protein, or to the vaccine itself. People with egg allergies are sometimes advised not to get the flu vaccine, as that vaccine is grown primarily from chicken eggs.
Common symptoms of an allergic reaction include a rash, skin irritation, cough, or trouble breathing.
The exact ingredients used in Pfizer’s new COVID-19 vaccine are proprietary and not publicly disclosed. The vaccine uses new technology and is coated in lipid nanoparticles, which have been used in drugs.
Some people react to almost any drug or vaccine, said Dr. Ashish Jha, dean of the School of Public Health at Brown University. The key is whether reactions to the vaccine are more common or more severe __ and that doesn’t seem to be the case so far, he said.
WHAT ARE OTHER SIDE EFFECTS?
Typical side effects of many vaccines include things like arm pain from the injection, fever, and muscle aches. In the Pfizer study, participants also reported fatigue, headache, and chills.
The most serious side effects are reported to regulators or health officials for further investigation. But it can often take time to determine if the vaccine caused the side effect or if the person was given the shot by coincidence before they got sick.
As for the COVID-19 vaccine, “it is so notorious that every little thing that happens all the time will be magnified,” Jha said.
“We should talk about it, we should be honest with people, but we should put it in context and help people understand,” he said. “There is a small proportion of people who have an allergic reaction to almost any drug.”
(This story was posted from a cable agency feed with no text changes. Only the title was changed.)
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