Pfizer chief says omicron seems milder, but could lead to more mutations

Pfizer chief Albert Bourla said on Tuesday that the omicron variant of the virus that causes Covid-1[ads1]9 appears to be milder than previous strains, but also appears to spread faster and could lead to more mutations in the future.

“I do not think it’s good news to have something that spreads fast,” Bourla told The Wall Street Journal during an interview at the newspaper’s CEO Council Summit. “Spreading fast means it will be in the billions of people and another mutation may come. You will not.”

White House Chief Medical Officer Dr. Anthony Fauci said this weekend’s reports from South Africa suggest that omicron is not as serious as first feared, while noting that more data is needed to fully assess the risk posed by the variant.

The South African Medical Research Council, in a report released on Saturday, said that most patients admitted to a hospital in Pretoria who had Covid did not need extra oxygen. The report also noted that many patients were admitted for other medical reasons and then found to have Covid.

Bourla warned that it is difficult to draw definitive conclusions from the wave of infections in South Africa right now. Only 5% of South Africans are over 60, and younger people usually have milder cases of Covid. However, many people in South Africa are also HIV-positive, which will probably lead to more serious Covid disease, he said.

The Pfizer chief said he expects the number of confirmed omicron cases to increase from dozens to millions over the next few weeks.

“We want a good understanding, let’s say before the end of the year about what it means for clinical manifestation,” Bourla said.

Pfizer may develop a vaccine targeting omicron by March 2022, Bourla said, but it is not yet clear if a new shot is needed. It will take a few weeks to find out if the current vaccines provide enough protection against the variant, he said.

Bourla said Pfizer is confident that its oral antiviral drug, Paxlovid, will fight omicron and all other variants of the virus that have appeared so far. The pill inhibits an enzyme the virus needs to replicate, known as a protease.

Most of the virus’ mutations have occurred on the spike protein so far, the mechanism it uses to attach to human cells, Bourla said. Vaccines and antibody treatments that target the nail protein may need updates when mutations occur on that part of the virus, he said.

However, it is much more difficult for the virus to mutate in a way that it can live without the protease enzyme that Paxlovid is targeting, he said.

“It is very difficult for the virus to create a strain that can live without this protease,” Bourla said. “It’s not impossible. It’s very difficult.”