Experts: Omicron could overtake delta in weeks
Some experts are warning that although evidence is still emerging, the highly concerning omicron variant is expected to overtake delta within weeks.
“I do expect omicron to displace delta in the coming weeks,” said Stephen Kissler, a disease modeler at the Harvard T.H. Chan School of Public Health, in a briefing Tuesday. “Unfortunately, just in time for the new year, we’re going to see quite a lot of omicron spreading.”
“The time frame for that is going to vary quite a bit” across the country, Kissler said. “In places that have already seen an increase in transmission, in the next six to eight weeks is pretty reasonable. … By the time we’ve detected the omicron variant, it’s already been in circulation for quite awhile, so that may even eat into that eight-week period.”
Earlier Tuesday, Pfizer CEO Albert Bourla speculated at an event hosted by the Wall Street Journal’s CEO Council that omicron likely will lead to millions of COVID-19 cases.
“Right now, the cases are in the dozens. In a few weeks, it will be in the millions,” Bourla said. “We will have a good understanding before the year’s end as to what exactly that means as far as its clinical manifestation.”
White House Chief Medical Adviser Anthony Fauci said at an administration briefing Tuesday that early laboratory data is expected next week on the efficacy of vaccines against the omicron variant.
The data will come by midweek from tests on how well the blood of vaccinated people knocks back a pseudovirus approximation of the omicron variant. By later next week, data will emerge on the efficacy of the vaccines against a live virus.
Centers for Disease Control and Prevention Director Rochelle Walensky emphasized new CDC guidance updated Monday night recommending a rapid test before any indoor gatherings.
“When you’re gathering together, for example, for the holidays in a multigenerational household, in addition to doing those other prevention interventions — like vaccination and maskwearing in public — you might want to do a test,” she advised.
Currently, there are about 103,800 COVID-19 cases, 6,800 hospitalizations and 1,100 deaths from all strains per day, overwhelmingly driven by delta, Walensky said at the briefing with Fauci and other officials.
The omicron variant has been detected in 18 states, she said.
“We expect that number to increase,” Walensky said.
The suspicions that omicron will overtake delta within weeks are based on the variant’s trajectory in South Africa, although Fauci noted the country is less vaccinated than the United States and is believed to have a higher proportion of immunocompromised people.
Kissler said the large population of previously infected people in South Africa following a delta surge pointed to omicron evading prior immunity.
“Presumably if delta had been protective against omicron in a very large way, against the transmission of omicron, I don’t think we would have seen as rapid an increase in omicron cases as we have,” he said.
Bourla cautioned it could be a few more weeks before there is more clarity on whether the vaccines designed to combat the original Wuhan strain protect against the omicron variant.