By Ahmed Aboulenein and Alexandra Alper
WASHINGTON (Reuters) - COVID-19 deaths and hospitalizations are "comparatively" low as the highly infectious Omicron variant of the coronavirus spreads, Centers for Disease Control and Prevention (CDC) Director Rochelle Walensky said on Wednesday as cases in the United States reached a record high.
"In a few short weeks Omicron has rapidly increased across the country, and we expect will continue to circulate in the coming weeks. While cases have substantially increased from last week, hospitalizations and deaths remain comparatively low right now," she said, referring to overall cases.
The current seven-day daily average of cases is up 60% over the previous week to about 240,400 per day, she said. The average daily hospitalization rate for the same period is up 14% to about 9,000 per day and deaths are down about 7% at 1,100 per day, Walensky told reporters at a White House briefing.
The average number of daily confirmed coronavirus cases in the United States hit a record high on Wednesday.
Early U.S. data suggests Omicron will have a lower hospitalization-to-case ratio than the Delta variant, top U.S. infectious disease Anthony Fauci said at the briefing, but COVID-19 vaccine boosters will be critical in tackling it.
"All indications point to a lesser severity of Omicron versus Delta," he said. "Boosters are critical in getting our approach to Omicron to be optimal."
Both Fauci and Walensky cautioned that data on deaths and hospitalizations tend to lag case data by two weeks.
Fauci said it was possible a second booster shot might be needed, but that it was not possible to know without first determining the durability of the protection offered by an initial booster, for which there is currently no data.
"Before we start talking about a fourth shot, it will be very important for us to determine the durability of protection, particularly against severe disease for the third shot booster of an mRNA and the second shot of a J&J," he said.
"Right now we don't have that information. It is conceivable that in the future we might need an additional shot but right now we are hoping that we will get a greater degree of durability of protection from that booster shot."
The government expects a contract for 500 million antigen tests, promised by President Joe Biden, to help address the surge in cases to be complete late next week, said White House COVID-19 response coordinator Jeff Zients.
"The Department of Defense and HHS are executing (this) on an accelerated timeline," he said.
Disease experts have questioned recent CDC guidance rules that halve the isolation period for asymptomatic coronavirus, saying they lack safeguards that could result in even more infections as the United States faces a record surge in cases.
"Unvaccinated people take much longer to clear the virus and not be infectious," said Dr. Eric Topol, director of the Scripps Research Translational Institute. "Some people clear the virus in a day; others take a week or more."
Walensky said the decision was based on research showing that up to 90% of COVID-19 transmission occurred within five days of infection. She said the agency balanced that with evidence that only a small minority of people with COVID have been willing to isolate for a full 10 days so far during the pandemic.
"We, at CDC, are working to provide updated recommendations, using science to ease the burden of lengthy isolation and quarantine recommendations. However, these recommendations will only work if people follow them."
(Reporting by Ahmed Aboulenein and Alexandra Alper; Additional reporting by Caitlin Webber and Chris Gallagher; Editing by Chizu Nomiyama and Aurora Ellis)