NEW YORK (REUTERS) - Millions of Americans appeared to be shrugging off public health warnings and travelling ahead of this week's Thanksgiving holiday, likely fuelling an alarming surge in coronavirus infections before a series of promising new vaccines become widely available.

With US Covid-19 infections hitting a record 168,000 new cases per day on average, Americans were flocking to airports against the advice of the Centres for Disease Control and Prevention (CDC), the US surgeon general and Dr Anthony Fauci, the nation's top infectious disease expert.

For Americans, the long holiday weekend, which begins on Thursday (Nov 26), is traditionally the busiest travel period of the year, and 2020 may prove to be no exception.

Some 1 million passengers passed through airport security gates on Sunday, the highest number since March. It was the second time in three days US air travel screenings surpassed 1 million, though the numbers are down nearly 60 per cent from the same time last year, the US Transportation Security Administration said.

Likewise, the American Automobile Association has forecast that 45 million to 50 million people will take to the highways over the holiday, compared with 55 million in 2019.

Soaring rates of coronavirus infections, deaths and hospitalisations have continued unabated.

The seven-day rolling average number of US Covid-19 deaths climbed for a 12th straight day, reaching 1,500 as of Monday, according to a Reuters tally of official data, while coronavirus hospitalisations nationally have surged nearly 50 per cent over the past two weeks.

To date, the highly contagious respiratory virus has killed over 255,000 Americans, with over 12 million infected since the pandemic began.

State and local government officials have reimposed a host of restrictions on social and economic life in recent weeks to tamp down the spread, as medical experts warn the surge is straining the resources of the nation's healthcare system.

Pleading with residents to stay home and avoid gatherings during the holiday season, Governor Andrew Cuomo reminded New Yorkers of the grim early days of the pandemic when as many as 800 people died in a single day across the state.

Hospitals and hope

Hospitalisations have spiked 122 per cent in New York state over the last three weeks, Mr Cuomo said, prompting the re-opening of an emergency medical facility on Staten Island.

Health officials have urged Americans to resist temptations to let their guard down, noting help is on the way in the form of promising vaccines nearing initial US distribution.

The head of the US campaign to rapidly deploy a vaccine said the first shots could begin to be administered to healthcare workers and other high-priority recipients as early as mid-December, within a day or two of receiving regulatory consent.

A vaccine from Pfizer Inc and its German partner BioNTech is expected to win authorisation from the US Food and Drug Administration (FDA), with a second vaccine from Moderna Inc headed for FDA review before year's end.

Late-stage trials of both vaccines have been about 95 per cent effective in preventing infection. The British maker of a third vaccine, AstraZeneca, announced its candidate has proved to be 90 per cent effective without serious side effects, and 700 million doses could be ready globally by late in the first quarter of 2021.

Fear and determination

Still, the imperatives of family and fatigue with Covid-19 restrictions have left many Americans defying health advice that could save their lives.

"We are not going to let Covid scare us," said Mr Brian McDonough, 47, a construction worker and diligent mask wearer who plans to spend Thanksgiving with his sister not far from his home in Worth, Illinois. He will bring pies for dessert.

"We get tested, we are negative, so life goes on," he said."Thanksgiving is Thanksgiving. Christmas is Christmas. New Year's is New Year's. If people die it's going to happen, and there's nothing we can do about it until we get a vaccine."

Ms Edie Taylor, 29, a building design specialist in Oakland, California, was less sanguine as she prepared to board a flight to her hometown of Birmingham, Alabama, to attend a family gathering and then stay on through New Year's.

"It's terrifying," said Ms Taylor, who said she would have changed her plans in light of the worsening pandemic, but after giving up her apartment in Oakland "I didn't have anywhere to live. I just have to get on that plane."

To be sure, many Americans are exercising greater caution.

Ms Donnalie Hope, 78, of Petersburg, West Virginia, is planning to make fresh cranberries, mash potatoes and her famous corn pudding for Thanksgiving, which she will spend with her visiting daughter and a neighbour.

Ms Hope said they would try to social distance in her home, and she planned to have rubber gloves and hand sanitiser on hand.

She acknowledged her guests might take off their masks in the home.

"I'm trying very hard to comply with the regs because I want this country to get back to where it belongs," Ms Hope said.