Serious allergic reactions to the Moderna COVID-19 vaccine are rare – with about 1 in 400,000 recipients suffering anaphylaxis after receiving the vaccine, according to the Centers for Disease Control and Prevention.
Ten people – all women – experienced a potentially deadly allergic reaction after receiving the first dose of the vaccine, with nine cases reported within 15 minutes after vaccination.
That statistic was more than 4 million doses administered between December 21 and January 10 and is equivalent to 2.5 cases per million doses administered, or 1 case per 400,000 doses, the agency said.
Nine of those who fell ill had a history of allergy or allergic reactions, including five who had a previous history of anaphylaxis.
Among the eight people with available follow-up information, all had recovered or been discharged.
No anaphylaxis-related deaths have been reported.
More women than men received their first dose of Moderna – which could explain the unusual finding that all 10 patients who had an anaphylactic reaction were women, explained the CDC.
The reaction requires immediate treatment, usually an injection of epinephrine. If left untreated, it can be deadly.
A total of 1,266 patients who received their first dose of Moderna experienced “adverse events” such as skin rashes or breathing problems, the agency said.
In December, a healthcare professional in Alaska was hospitalized after receiving the Pfizer / BioNTech coronavirus vaccine and experiencing an anaphylactic reaction – which has also been reported in the UK.
“There is a strong female predominance of anaphylaxis case reports for both vaccines,” noted the CDC in its Friday report.
“Finally, many people who experienced anaphylaxis after receiving any of the vaccines had a history of allergies or allergic reactions, with several having experienced an episode of anaphylaxis in the past.”