With the US health care system already under immense strain due to high hospitalisation numbers, the country’s top infectious diseases expert Dr Anthony Fauci has warned of a likely sharp post-holiday spike in new coronavirus cases.

“We are really at a really critical point,” Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNN on Sunday, referring to the health care system.

On an average day, some 120,000 people were in hospital across the US with COVID-19 complications, he noted.

Despite warnings against travelling for Christmas, people had been packing airports and taking to the roads, Fauci said, prompting his concern about a “surge” in infections after the holiday season.

On Wednesday, the country set a single-day air travel record since the start of the pandemic, when nearly 1.2 million people took flights, according to federal government data.

Fauci continued to urge people to get vaccinated when they can, even as he acknowledged that the rollout started earlier this month had been slow.

Governors have complained of problems in the logistical chain that have delayed inoculation plans.

Fauci projected that the general population will start to get vaccinated by April and that the country could see a return to some kind of normality by autumn.

The Trump administration’s forecast for the vaccine roll-out is a bit brighter, with a prediction of mid-summer for the country to reach herd immunity.

COVID-19 has now killed one of every 1000 people in the United States, slightly more than 11 months since the first case was reported.

According to data compiled by Johns Hopkins University, there were 331,561 confirmed coronavirus fatalities in the nation as of Saturday afternoon.

The US Census Bureau estimates that the population is currently about 330,750,000.

Almost 19 million people have been infected with the deadly coronavirus in the US.

The number of infections in the United States is by far the highest in the world – more than the two countries with the second and third-highest rate, India and Brazil, combined.