In the first week and a half of the U.S. Covid-19 vaccine effort, the CDC said there were 21 additional confirmed cases of severe allergic reactions known as anaphylaxis, giving the total cases at 29 out of 1.9 million doses .
By comparison, the rate of severe allergic reactions to the flu vaccine is 1.3 per 1 million doses.
“The anaphylaxis rate for Covid-19 vaccines may seem high compared to flu vaccines. But I want to assure you that it is still a rare outcome,” said Dr. Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, told a news conference.
The allergic reactions came within minutes of the vaccination, the CDC said. The CDC has information on 20 of the 21 patients and all have recovered.
Anaphylaxis is a serious allergic reaction, but with treatment it usually goes away quickly.
The CDC has so far seen no evidence of geographic group reactions and no hint that there were ‘bad’ lots. The vaccines given to people who have had reactions do not come from the same fate.
Of the people who had the severe allergic reaction, 17 had a documented history of allergies, Messonnier said, including drugs, medical products, food and insects.
People who have had an allergic reaction to the first dose should not receive the second dose for now.
“We have adjusted our recommendations as we learn more,” Messonnier said.
The CDC has said it will continue to monitor allergic reactions in people receiving the vaccine. The CDC team said that people may report more cases or allergic reactions than are usually reported.
“It is possible that media attention surrounding the national COVID-19 vaccination program and increased awareness of reports of anaphylaxis influenced the behavior and practices of the vaccine recipient and healthcare provider, including increased concern and anxiety, higher suspicion of anaphylaxis , and lower threshold for early treatment of suspected cases, leading to an increase in the diagnosis of suspected anaphylaxis and corresponding stimulated reporting above baseline to VAERS (the vaccine reporting system), the CDC team in the MMWR report written.
Risk versus benefit
“The known and potential benefits of current Covid-19 vaccines outweigh the known and potential risks that Covid-19 carries,” Messonnier said. “However, that does not mean we would not be able to see potentially serious health events in the future.”
The CDC also saw no other worrying serious reactions to the vaccines.
“We know that safety is one of the biggest concerns about Covid-19,” Messonnier said.
“Vaccine safety has been crucial during the development process, and the continued safety of these vaccines, as they are administered to the public, is of paramount importance to the federal government,” she added.
In clinical trials, the vaccines have been given to more than 70,000 people. But doctors know that more rare events can start to appear when given to millions of people. As of Tuesday, the vaccine has been administered to 4.8 million people in the U.S., the CDC said.
“Ensuring public knowledge and confidence in the safety of these vaccines, both initially and during long-term use, is an essential part of our successful national vaccine efforts,” Messonnier said.
Messonnier said she understands how people can be nervous about the vaccine.
“I can tell you that my parents, who are in their 80s, are also nervous,” Messonnier said. “We are studying these vaccines carefully and our systems that can look at unwanted incidents are incredibly strong. We are not seeing any alarming signals. The only thing we have seen is these severe allergic reactions.”
The CDC emphasizes that any website that provides coronavirus vaccines must be prepared to process a response immediately. People are asked to stay on site for at least 15 minutes after vaccination to make sure they can be treated quickly and correctly if they experience a reaction; people who have had an allergic reaction to a vaccine in the past are asked to stay for 30 minutes.
Messonnier said the risks of the vaccine are very acceptable.
“I still believe that the risk of Covid and the risk of poor outcomes, especially among senior citizens, is essential for people to continue to be vaccinated as soon as it is at their disposal,” she said.