Pfizer Chief Executive Albert Bourla said Monday that the company’s two-dose vaccine may not provide strong protection against infection with the omicron Covid variant, and that the original vaccine lost some of its efficacy in preventing hospitalizations.
In an interview at the JPMorgan Healthcare Conference, Bourla emphasized the importance of a third shot to strengthen people’s protections against omicron.
“These two doses are not enough for omicron,” Bourla said. “The current third dose provides good protection against death and decent protection against hospitalisation.”
Bourla said omicron is a harder target than previous variants. Omicron, with dozens of mutations, can evade some of the protection provided by Pfizer’s original two shots.
“We’ve seen very clearly that the first thing we lose with the second dose is protection from infection,” Bourla said. “But after two months, the intensity of hospitalizations in the past has also decreased. I think that’s a concern for everyone.”
Real data from the UK found that two doses of the vaccine were 52% effective at preventing hospitalisation 25 weeks after the second dose, according to the UK Health Security Agency.
According to UK data, a two-dose vaccine from Pfizer or Moderna is only about 10% effective at preventing omicron infection 20 weeks after the second dose.
On the other hand, booster doses are up to 75% effective in preventing symptomatic infections and 88% effective in preventing hospitalizations, according to the data.
However, Bourla said it was unclear how long the booster dose would provide protection against the new coronavirus. The UK Health Safety Agency also found that the booster was only 40 to 50 percent effective against infections 10 weeks after the injection.
“The question mark, how long will the protection from the third dose last,” Bourla said.
The Centers for Disease Control and Prevention now recommends that some people with compromised immune systems receive four shots, three primary doses, and one booster shot. Israel has launched a fourth dose of Pfizer for people over 60. Israel found a fourth dose boosted protective antibodies fivefold.
Bourla told CNBC earlier on Monday that Pfizer would have a vaccine specifically for omicron ready in March, but said it was unclear if such a vaccine would be needed.
Bourla also told CNBC that more testing is needed to determine if a fourth dose is needed.