Covid-19 vaccines have triggered severe allergic reactions in 29 people in the United States to date

At least 29 people in the United States have developed severe allergic reactions to Covid-19 vaccines, federal health officials said on Wednesday.

The rate is much higher than for the seasonal flu vaccine, officials from the U.S. Centers for Disease Control and Prevention said. But serious reactions were rare and resulted in no deaths, and they encouraged the use of the injections.

The 29 cases date back to Jan. 5 and are out of more than 5.3 million doses that have been administered to date, the CDC said.

The rate of 5.5 cases of anaphylaxis, a potentially fatal allergic reaction, for every million doses of Covid-19 vaccine administered to date compares to the rate of 1.3 cases for every million doses of influenza vaccine , according to the CDC.

Still, cases of anaphylaxis are “extremely rare,” said Nancy Messonnier, director of the CDC’s National Vaccination and Respiratory Disease Center, which leads the agency’s Covid-19 vaccination efforts.