Compared to the problems encountered by makers of adenovirus COVID-19 vaccines, it’s been a relative cakewalk for the overwhelmingly successful mRNA vaccines produced by Pfizer-BioNTech and Moderna.
The European Medicines Agency is trying to determine if the mRNA shots can trigger an allergic skin reaction called erythema multiforme or two kidney disorders. It has requested additional data from Pfizer, BioNTech and Moderna.
"We take adverse events that are potentially associated with our COVID-19 vaccine, BNT162b2, very seriously," Pfizer said in a statement. "We closely monitor all such events and collect relevant information to share with global regulatory authorities."
Hundreds of millions of people have received Pfizer's vaccine, the company's spokesperson pointed out.
"Serious adverse events that are unrelated to the vaccine are unfortunately likely to occur at a similar rate as they would in the general population," the company representative said.
Moderna did not immediately respond to a request for comment.
Since the mRNA shots started winning authorizations back in December, it’s been generally smooth sailing for the programs. In June, the FDA required Pfizer-BioNTech and Moderna to put a warning on their labels about rare cases of heart inflammation. In July, the EMA also studied a possible link. Both watchdogs still concluded that the benefits of the vaccines far outweigh the risks.
The European regulator did not reveal how many people had developed the new possible side effects. More than 330 million doses of the Pfizer-BioNTech vaccine have been administered in Europe, compared to more than 43 million doses of the Moderna shot.
In addition to production and supply problems, safety concerns have swirled around the adenovirus COVID-19 vaccines produced by AstraZeneca and Johnson & Johnson. In June, the European Commission revealed that it would not renew contracts with either vaccine provider.
Erythema multiforme causes round skin lesions which may also affect mucous membranes in internal body cavities. Nephrotic syndrome causes the kidneys to leak too much protein into the urine. Glomerulonephritis causes inflammation of the tiny filters in the kidneys. Symptoms of the kidney disorders are fatigue, bloody or foamy urine, and oedema, a swelling of the eyelids, feet or abdomen. Some of the patients under examination had pre-existing kidney ailments.
The EMA also is looking into menstrual side effects with all of the available adenovirus and mRNA COViD-19 vaccines.
Pfizer said that it and BioNTech are supporting the EMA's Pharmacovigilance Risk Assessment Committee investigation with data and analyses.