CDC: Anaphylaxis rate with COVID Vax 10 times higher than that of influenza vaccines

Although uncommon, the rate of anaphylaxis after COVID-19 mRNA vaccines appeared approximately ten times that documented for influenza vaccines, CDC officials said Wednesday.

Overall, 21 cases of anaphylaxis were reported after COVID vaccination of about 1.9 million doses given on December 23, according to a first report Weekly morbidity and mortality report release. That equates to 11.1 cases per million compared to an estimated 1.3 cases per million after the inactivated flu vaccine, agency officials said in a call to the media.

They noted that 29 confirmed cases of anaphylaxis are currently being reported with the Pfizer / BioNTech and Moderna vaccines. In addition, officials said, the MMWR The December 14-23 report focuses on the Pfizer vaccine, as the Modern vaccine was not available until December 21st. However, there is not enough data to see a difference in risk between vaccines.

So far no deaths have been seen from anaphylaxis.

Nancy Messonnier, MD, director of the National Center for Vaccination and Respiratory Disease at the CDC, noted that these events were rare and that the benefits of vaccination against COVID-19 outweighed the risks. Also, comparing them to the “don’t pass the time” flu figures when there are more than 2,000 deaths from COVID-19 every day in the US

“It’s still a good value proposition,” he said. “Even if the rate is higher than what we see after routine vaccinations, anaphylaxis is still scarce.”

Of the 21 cases reviewed a MMWR, 18 had documented allergies or allergic reactions to medications, medical products, food, or insect bites, and seven had experienced anaphylaxis in the past, including one after a rabies vaccine and one after a influenza A (H1N1) vaccine.

Messonnier acknowledged the millions of people who have food allergies or insect bites and stressed the difference between “someone who had a mild allergic reaction in their childhood and someone with a severe allergic reaction to next week”.

“A lot of people have a history of allergy to bee stings or food and the fact that people in this group have anaphylaxis … may not mean that allergic reactions put them at risk, but yes, ”he added.

Messonnier noted that CDC guidelines state that anyone with a history of anaphylaxis for any reason should talk to their doctor before vaccination and doctors should exercise their judgment.

CDC officials said anyone with a history of anaphylaxis receiving the vaccine should be observed for 30 minutes later, as people who previously had anaphylaxis were at risk of having it again.

The agency has recently updated its interim guidelines for clinicians on vaccine contraindications, adding that those with an immediate allergic reaction to the first vaccine should not receive a second dose.

Seventeen of the 21 cases were among those with a history of anaphylaxis and the median time from vaccination to onset of symptoms was 13 minutes, although about 70% of patients had onset of anaphylaxis. symptoms in 15 minutes. The mean age of the patients was 40 years and 19 were women.

He MMWR The report noted that female predominance had previously been seen for immediate hypersensitivity reactions to the influenza A (H1N1) vaccine. But the disproportion with COVID vaccination could simply be due to more women than men receiving the Pfizer / BioNTech vaccine, the authors said.

Nineteen patients were treated with epinephrine, 17 were treated in the emergency department and four were hospitalized, including three in intensive care. Among 20 with information available, all were discharged at home.

In addition, Messonnier briefly addressed reports from health workers choosing not to be vaccinated, saying she was “definitely concerned” about it.

“It is very important that we receive the right information from healthcare workers and quickly dispense with misinformation,” he said. “We need them not only to protect themselves, but to educate their patients so that everyone understands these vaccines … they have a good safety profile, they are working and they can help us end this pandemic.”