According to Reuters, on the 24th local time, the United StatesPfizer IncAlbert Bourla, the company's chief executive, once again said he had tested positive for novel coronavirus. "I feel good and have no symptoms," Alberle said in a statement.

It is understood that this is the second time that Abel has infected COVID-19. On August 15, Alberle announced that he had tested positive for novel coronavirus. He said at the time that he was suffering from mild symptoms and was being quarantined and followed public health precautions. He had received four doses of COVID-19 vaccine developed by Pfizer Inc and its German partner BioNTech before the first infection.

"I haven't been vaccinated with a new bivalent vaccine because according to the guidelines of the Centers for Disease Control and Prevention (CDC), I need to wait three months after I first infected novel coronavirus in mid-August," Alberle said.

BioNTech and Moderna Inc's updated COVID-19 vaccine target both the original virus strain and Omicron BA.4 and BA.5 variants, so they are called bivalent vaccines. According to the latest data, these two subtypes account for 84.8% and 1.8% of all popular variants in the United States, respectively.