Live updates: follow the latest news on Omicron
The US has passed a record number of Covid-19 hospital admissions set in January 2021, amid an uncontrolled spread of the highly contagious Omicron coronavirus variant.
More than 145,000 patients are in US hospitals with Covid-19 as of Tuesday, the US Department of Health and Human Services reported, higher than the record level in January 2021 when more than 142,000 were admitted.
The federal data marks a devastating milestone as healthcare systems are under dangerous levels of stress, after two years of the pandemic.
Doctors and nurses are struggling to meet greater demand than ever, while some staff members are infected, leading to staff shortages in some healthcare centres.
The US Centres for Disease Control and Prevention and some states are asking healthcare workers to shorten their isolation periods after they test positive, to help meet patient needs.
The Omicron variant accounts for more than 98 per cent of Covid-19 cases spreading in the US, the CDC estimates, and the country is seeing an enormous rise in known cases with a seven-day average of daily infections at more than 680,000.
"We are at a very, very different point in the pandemic than we were two years ago," Dr Jacob Lemieux, an infectious disease specialist at Massachusetts General Hospital in Boston, said on Tuesday.
"There's a very high numbers of hospitalisations, but there is light at the end of the tunnel. We're still in the tunnel, but the vaccines work."
An overwhelming majority of the cases are among unvaccinated people. But as people return to work and school after the holidays, demand for at-home rapid tests and PCR testing have grown dramatically.
"We've also learnt public health measures that work, like masking and distancing," Dr Lemieux said. "And we are about to see the rollout of medicines that are currently have limited availability, but that availably will increase."
While Omicron is perceived to be a milder variant, experiences with infection are not uniformly "mild" for everyone.
It has been suggested that three vaccine doses provide the best protection against the variant and only 36 per cent of the US population has had a third dose.
Widespread infections continue to endanger immunocompromised and unvaccinated people at higher risk of severe illness and death from Covid-19.
The US leads the world in known coronavirus infections at more than 61 million cases as of Tuesday, according to Johns Hopkins University data.
Because hospitalisations and deaths lag behind infections, it is expected that admittances will only rise from the record seen this week.
The World Health Organisation on Tuesday warned against treating the pandemic as an endemic illness, akin to the seasonal flu.
"Endemic means that there isn't an epidemic and very clearly, there is an epidemic going on right now, cases are surging," Dr Lemieux said.
"Will it continue the trend of losing virulence over time? We hope so. But we don't know for certain."
