Washington (AFP)
Cases of a severe allergic reaction to Moderna's Covid-19 vaccine are "rare", and affected only 10 people out of more than 4 million first doses administered in the United States, health authorities said on Friday.
None of these ten cases resulted in death.
"Based on these preliminary checks, anaphylactic shock (severe allergic reaction, editor's note) after injection of Moderna's vaccine against Covid-19 is a rare event," wrote the Centers for Disease Prevention and Control (CDC ).
The main federal public health agency in the country studied, over the period from December 21 to January 10, 108 possible reported cases of allergic reaction out of 4,041,396 first doses injected.
Only ten cases actually turned out to be anaphylactic shock, six of which required hospitalizations (the other four were treated in an emergency department).
This represents 2.5 anaphylactic shocks for a million injections.
That rate was 11.1 shocks per million injections with Pfizer's vaccine, according to a previous CDC study.
Of the ten cases, nine people had a known history of allergic reactions, for example to certain drugs or foods, but not after injection of a vaccine.
Symptoms began within 15 minutes of the injection for nine of them, and beyond 30 minutes in one.
Notable fact: the 10 people involved, who were between 31 and 63 years old, were all women.
Such a predominance was also observed for allergic reactions to Pfizer's vaccine, but could be influenced by the fact that a greater proportion of women received a dose of the vaccine (about two thirds to one third of men).
The infrastructure where vaccinations are carried out must be equipped to treat severe allergic reactions, and be able to transport patients to hospital if necessary, the CDC said.
© 2021 AFP