WASHINGTON – An Alaska health care worker had a severe allergic reaction after receiving Pfizer’s coronavirus vaccine Tuesday. These symptoms appeared within minutes and required an overnight stay in hospital.
The middle-aged worker had no history of allergy but had an anaphylactic reaction that started 10 minutes after receiving the vaccine at Bartlett Regional Hospital in Juneau, Alaska, a hospital official said. She had a rash over her face and trunk, shortness of breath, and an increased heart rate.
Dr. Lindy Jones, the hospital’s emergency room medical director, said the worker was first given a shot of adrenaline, a standard treatment for severe allergic reactions. Her symptoms subsided, but then came back and was treated with steroids and an adrenaline drop.
When doctors tried to stop the drip, her symptoms reappeared, so the woman was taken to the intensive care unit, which was observed throughout the night, and then taken off the drip early Wednesday morning, Dr. Jones. Dr. Jones said the woman is feeling fine, continues to be excited about the vaccine, and will be released later Wednesday.
Although the Pfizer vaccine was shown to be safe and 95 percent effective in a clinical study of 44,000 participants, the Alaska case is likely to heighten concerns about possible side effects. Experts described the woman’s symptoms as potentially life-threatening and said they may ask for stricter guidelines to ensure recipients are carefully monitored for side effects.
Dr. Paul A. Offit, a vaccine expert and a member of an outside advisory panel that recommended the Food and Drug Administration to approve Pfizer’s emergency vaccine, said appropriate precautions have already been taken. For example, requiring recipients to remain in place for 15 minutes after receiving the vaccine helped ensure that the woman was treated quickly.
“I don’t think this means we should stop vaccine distribution,” he said. “Not at all.” But he said the researchers need to find out “what component of the vaccine is causing this response”.
Millions of Americans are expected to be vaccinated with the Pfizer vaccine by the end of the year. As of Wednesday night, it was unclear how many Americans had received it so far. Alex M. Azar II, the secretary for health and human services, said his department would release these data “several days or maybe a week later.”
The Alaska woman’s response was thought to be similar to the anaphylactic reactions two health workers in the UK had after receiving the Pfizer BioNTech vaccine last week. How they both recovered.
These cases are likely to happen on Thursday when F.D.A. Scientists are scheduled to meet with an outside expert group to evaluate Moderna’s coronavirus vaccine, which uses the same technology as Pfizer’s.
Although the Moderna and Pfizer-BioNTech vaccines are similar in their ingredients, it is not clear whether an allergic reaction to one would occur with the other. Both are made up of genetic material called mRNA, which is trapped in a bubble of oily molecules called lipids.
Moderna and Pfizer use different combinations of lipids. Dr. However, Offit said that in both vaccines the bladders are coated with a stabilizing molecule called polyethylene glycol, which he views as a “leading contender” for causing an allergic reaction, although he stressed that further investigation is needed.
The Pfizer study did not identify serious adverse events from the vaccine, although many participants experienced pain, fever, and other side effects. The Alaskan woman’s response was thought to be related to the vaccine because it occurred so quickly after the shot.
A Pfizer spokeswoman, Jerica Pitts, said the company doesn’t have all the details of the case, but is working with local health officials. The vaccine includes a warning that medical treatment should be available in the event of a rare anaphylactic event, she said. “We will closely monitor any reports suggestive of serious post-vaccination allergic reactions and update the labeling language as necessary,” said Ms. Pitts.
After workers in the UK fell ill, authorities there warned against giving the vaccines to anyone with a history of severe allergic reactions. You later cleared their concerns, Changed the wording of “Severe Allergic Reactions” to stipulate that the vaccine should not be given to anyone who has ever had an anaphylactic reaction to a food, medicine or vaccine. That type of response to a vaccine is “very rare,” they said.
Pfizer officials said the two Britons who had the reaction had severe allergies in the past. A 49-year-old woman has had egg allergies in the past. The other, a 40-year-old woman, had a history of allergies to various drugs. Both wore EpiPen-like devices to inject adrenaline in the event of such a reaction.
Pfizer has said that its vaccine has no egg ingredients.
The UK update also said a third patient had a “possible allergic reaction” but did not describe it.
In the United States, federal regulators on Friday gave adults 16 years and older a full approval for the vaccine. Healthcare providers have been warned not to give the vaccine to anyone with a “known history of a severe allergic reaction” to any component of the vaccine. This is a standard warning for vaccines.
But because of the British cases, F.D.A. Officials said they would ask Pfizer to step up surveillance for anaphylaxis and provide data on it once the vaccine comes into use. Pfizer also said it is recommended that the vaccine be given in environments with access to anaphylaxis treatment equipment. Last weekend, the Centers for Disease Control and Prevention announced that people with severe allergies can be safely vaccinated, with close monitoring for 30 minutes after receiving the shot.
Anaphylaxis can be life-threatening, with difficulty breathing and drops in blood pressure that usually occur within minutes or even seconds of exposure to a food or drug, or even a substance such as latex, to which the person is allergic.
Carl Zimmer contributed to the reporting.