An unrelenting US coronavirus surge pushed besieged hospitals further to the brink as the United States pressed on with its immunisation rollout and prepared to ship nearly 6 million doses of a new vaccine on the cusp of winning regulatory approval.

Covid-19 hospitalisations rose to record heights for a 19th straight day, with nearly 113,000 coronavirus patients counted in US medical facilities nationwide on Wednesday, while 3,580 more perished, the most yet in a single day.

The virus has claimed almost 308,000 lives in the United States to date, and health experts have warned of a deepening crisis this winter as intensive care units (ICUs) filled up and hospital beds overflowed into hallways, according to Reuters.

“We expect to have more dead bodies that we have spaces for them,” Los Angeles Mayor Eric Garcetti said at a briefing, adding that the country's second largest city had fully exhausted its ICU capacity.