Drugmakers are trying to develop new vaccines that target the omicron variant, a coronavirus strain that has mutations that suggest it could evade immunity provided by vaccination or natural infection.
Moderna Chief Medical Officer Dr. Paul Burton said in an interview on NBC News Now's Hallie Jackson Now that the company has already started working on a version of its vaccine to address the new variant. Pfizer and BioNTech said they could develop a omicron-specific vaccine within six weeks and ship initial batches within 100 days. Johnson said it will progress the vaccine as needed and that it is pursuing a modified vaccine.
It is not known if a new vaccine will be needed.
The existing vaccines proved to be highly effective or the strain in question just fizzled out, according to John Moore, professor of microbiology and immunology at Weill Cornell Medical College.
He said that the delta variant remains the most contagious version of the virus, but he said that the vaccines have still proven to offer protection against it.
When the delta variant became dominant in the summer, unvaccinated people were 4 times more likely to die, 10 times more likely to be hospitalized and 11 times more likely to die of Covid, according to a study by the Centers for Disease Control and Prevention.
The existing vaccines worked against the delta variant.
It wasn't necessary to manufacture and roll out a variant vaccine specific to delta at the time, Moore said. That is a huge investment when you have to go out and make new products and get it checked out by the FDA, even if it is under a fast track procedure, he said.
The beta variant, first identified in South Africa, was another strain that was thought to necessitate an updated version of the vaccine. The existing vaccines were significantly less protective against infection with beta, but the variant never spread widely in North America, Europe and other parts of the world, like delta did, he said. He added that it might have been necessary to develop a shot for beta but the variant didn't take off.
Moore said that was the key unknown for the omicron. Is omicron going to be like beta and not outcompete delta and just fade away or is it going to be a super version of delta and something that we need to be concerned about? He said that there are a large number of unknowns that will emerge in the next few weeks that will determine whether or not they will need to roll a new vaccine.
The World Health Organization said last week that preliminary evidence showed an increased risk of reinfection with this variant compared to other variants of concern. The new strain also has mutations that are associated with higher transmissibility and possibly reduced antibody protection, it said.
Jerica Pitts, a Pfizer spokesman, said none of the previous variants had escaped the protection of its vaccine in laboratory studies or real-world observations. The company said that it first needs to understand how it can neutralize the variant in lab studies to decide whether or not to ask the FDA to approve a new vaccine.
The company said it needed to see whether omicron can beat delta outside the current hot spot in South Africa or if it spreads quickly in the country. If health officials see a significant increase in the number of patients hospitalized with Covid, there would be a good reason to launch a variant-specific vaccine, according to Dr. Michel Nussenzweig, an immunologist at Rockefeller University in New York.
He wrote in an email, but that's not clear yet. There is no real data available, just speculation based on the rates of reporting the sequence, which is going up rather quickly, and the data on viruses with related mutations. Moore said that the chances of a variant blowing off all vaccine immunity are very, very, very, very slim even if the vaccines take a hit against omicron. If there is a worst-case scenario, you would expect to see more infections in vaccinated people, but you wouldn't expect to see a huge increase in deaths because there would still be protective immunity.