US President-elect Joe Biden will get the coronavirus vaccine as soon as next week, transition officials said on Wednesday, as US authorities try to build public confidence in a measure that promises to stanch the deadly pandemic.

Vice-president Mike Pence will get the vaccine on Friday, the White House said.

Both men will receive the shot publicly in an effort to boost confidence in the safety of the vaccine, which will become widely available to the public next year.

“I don’t want to get ahead of the line but I want to make sure that we demonstrate to the American people that it is safe to take,” Biden said at an event earlier on Wednesday. Biden, 78, is in a high-risk category for the coronavirus because of his age.

Biden has vowed to make the fight against the virus his top priority when he takes office on January 20. President Donald Trump, who lost the November 3 election to Biden, has frequently downplayed the severity of the pandemic, which has killed 304,187 Americans so far, and feuded with his top public health officials.

Trump will get the vaccine himself as soon as his medical team determines it is best, White House press secretary Kayleigh McEnany said on Tuesday. The president was hospitalised after testing positive for Covid-19 this fall.

Initial doses of the vaccine, which became available in the US this week, have been set aside for doctors, nurses and other front-line medical workers, along with residents and staff of nursing homes and some US government officials.

US officials aim to get 2.9 million doses of the vaccine, developed by Pfizer Inc and German partner BioNTech SE, by week’s end.

One health worker in Alaska had a severe allergic reaction after receiving the vaccine, officials said on Wednesday in what is believed to be the only adverse reaction so far in the US.

A significant portion of the American public has shown disdain for basic public health recommendations, such as wearing a mask, and only 61% of respondents in a recent Reuters/Ipsos poll said they were open to getting vaccinated.

Scientists believe that “herd immunity” against the virus could be achieved once about 70% of the population has been exposed to it, either through natural infection or a vaccine.

Some 16.7 million Americans have been infected so far, equal to roughly 5% of the population.

Pence’s wife, Karen, and surgeon general Jerome Adams also will get the vaccine on Friday, the White House said.

Biden’s transition team did not say when vice president-elect Kamala Harris would get the vaccine.