A pharmacist dilutes the Pfizer COVID-19 vaccine as he prepares it to administer to the staff and residents of Goodwin House Bailey’s Crossroads, an elderly community in Falls Church, Virginia, on December 30, 2020.
Brendan Smialowski | AFP | Getty Images
The Covid-19 vaccine appears to cause severe allergic reactions at a significantly higher rate than other vaccines among the first wave of Americans to receive life-saving immunizations, the US Centers for Disease Control and Prevention said on Wednesday.
Although still rare, the CDC said there were 21 cases of anaphylaxis – a serious and life-threatening allergic reaction that rarely occurs after vaccination – among the nearly 1.9 million people who received their first injection of Covid-19 vaccine from Pfizer in mid – late December, according to a study published in the CDC’s Morbidity and Mortality Weekly Report on Wednesday.
That would mean that about 11 people in every million vaccinees are likely to experience anaphylaxis, according to CDC data – about 10 times more than the flu vaccine.
Dr. Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, told reporters on a conference call that inoculations were safe for public use and that serious allergic reactions – although major – were still considered rare.
“The rate of anaphylaxis for Covid-19 vaccines may seem high compared to flu vaccines, but I want to reassure them that this is still a rare result,” said Messonnier in the call before the study was launched. She added that the data applies to vaccines from Pfizer and Moderna, which use similar mRNA technology.
Of the 21 people who experienced severe allergic reactions, 17 of them had a documented history of allergies or allergic reactions. Seven of those people had a history of anaphylaxis, the study found.
Most people experienced the symptoms 15 minutes after applying the vaccine, although anaphylaxis can occur hours after someone is vaccinated, the CDC said. Among the 20 people with available follow-up information, all recovered or were discharged home, the study concluded.
Most people experienced the symptoms 15 minutes after applying the vaccine, although anaphylaxis can occur hours after someone is vaccinated, the CDC said. Among the 20 people with available follow-up information, all recovered or were discharged home, the study concluded.
“Of course, we would all expect any vaccine to have zero adverse events, but even with 11 cases per million doses administered, it is a very safe vaccine,” said Messonnier. She added that “tremendous efforts” are underway to try to determine exactly what is causing the serious allergic reactions.
The coronavirus is killing an average of 2,670 people in the U.S. every day, according to a CNBC analysis of data compiled by Johns Hopkins University, making the vaccine a “good value proposition,” said Messonnier.
According to the provisional guidance from the CDC’s Immunization Practices Advisory Committee, last updated in December, everyone should be observed for 15 minutes after vaccination to ensure that they do not develop symptoms. People with a history of anaphylaxis should be observed for 30 minutes, the committee advised.
The committee also suggested that people who developed anaphylaxis after the first dose should not receive a second dose, as both drugs require two injections with weeks apart for full effectiveness. The CDC study said that each vaccination site should have supplies like epinephrine ready to treat patients who may develop severe reactions.
“Fortunately, we know how to treat anaphylaxis and we have made arrangements to ensure that, at the immunization sites, people who give the vaccine are ready to treat anaphylaxis,” said Messonnier.