BERLIN—Swiss drugs regulator Swissmedic said on Wednesday it is examining potential risks in connection with bubbles that appeared in vials of COVID-19 vaccine boosters retooled to target the Omicron variant of the coronavirus.
Swissmedic said it had been informed by vaccination centers of the appearance of bubbles during the preparation of the updated vaccine from Pfizer and BioNTech targeting the original version of the coronavirus and the BA.1 Omicron variant that led to a record surge in cases last winter.
“Vials of the batch concerned contained bubbles after being removed from the fridge,” said Swissmedic, adding that the phenomenon seems to be accentuated when the syringes were prepared several hours in advance.
Cantons and vaccination centers have been informed as a precaution, the regulator said. It added that it was looking into possible causes.
Swissmedic had temporarily approved the booster shot in early October, but said it was too early to approve the bivalent booster targeting the currently circulating BA.4 and BA.5 Omicron subvariants in addition to the original virus, which is being used in the United States despite less available data.
A BioNTech spokesperson said Pfizer was in charge of the supply chain and distribution in Switzerland and had no further immediate comment.
