Joe Biden announced new actions to combat the coronavirus in the US, including a nationwide campaign encouraging vaccine boosters, an expansion of at-home tests and tighter restrictions on international travel.

Buffeted by the emergence of the Omicron variant and a political backlash from Republicans, the US president visited the National Institutes of Health in Bethesda, Maryland, on Thursday and laid out a pandemic battle plan for the winter months.

“My plan pulls no punches,” Biden said “It is a plan that should unite us.”

Biden announced steps to ensure that the nearly 100 million eligible Americans who have not yet received their booster shot do so as soon as possible, the White House said. There is new urgency to the effort after the first US case of the Omicron variant of Covid-19 was identified in California on Wednesday and a second one in Minnesota on Thursday.

The president pledged to expand pharmacy availability during December while pharmacy partners send millions of texts, calls and emails to eligible customers with information on how to schedule an appointment or walk in for a booster shot.

There will also be a public education campaign to encourage adults to get boosters, with a particular focus on the elderly. It will feature paid advertising across multiple channels, engagement with community organisations and media campaigns.

The fight against the coronavirus in the US has politically divided the country with Republicans often seeking to undermine efforts to mandate public health policies around masks and vaccines.

Biden directly took on the politicization of health policy, calling it a “sad commentary” on the state of politics in the US. He said his new measures should appeal to all Americans. “This is a moment we can put the divisiveness behind us, I hope,” he said.

But, in addressing the threat from the Omicron variant, Biden threw a veiled punch at the often chaotic record of his predecessor, Donald Trump, whose efforts to combat the coronavirus were often marked by inconsistencies, quack cures and conspiracy theories. “We are going to fight this variant with science and speed, not chaos and confusion,” he said.

Anthony Fauci, chief medical adviser to Biden on Covid-19, told reporters at the White House on Wednesday that boosting was “very important”, particularly when considering the rise in antibodies following a third dose.

He added: “Even though we don’t have a lot of data on it, there’s every reason to believe that kind of increase that you get with the boost would be helpful at least in preventing severe disease of a variant like Omicron.”

The emergence of Omicron has demonstrated the tenacity of the virus, which continues to drag down Biden’s political fortunes. Voters are divided on his handling of the pandemic, with 47% approving and 49% disapproving, according to a recent Washington Post/ABC News poll.

But the White House defended his record, for example by pointing out that when he came into office more than half of schools were closed, where today 99% are fully open and in person. On Thursday, the president will unveil actions to get more children aged five and older vaccinated.

These include the launch of hundreds of family vaccination clinics across the country, offering a “one-stop shop” of first shots for parents, teenagers and children, and boosters for those eligible. There will be “family vaccination days” with hundreds of community health centres across the country hosting family vaccination clinics throughout December.

Biden also set out a plan to ensure that Americans have access to free at-home testing. More than 150 million people with private insurance will be able to get at-home tests reimbursed; for those not covered, at-home tests will be distributed through health centres and rural clinics.

With the threat posed by the Omicron variant still uncertain, early next week the US will tighten pre-departure testing protocols by requiring all inbound international travellers to test within one day of departure, regardless of nationality or vaccination status.

In a briefing call with reporters, a senior administration official said: “We have really strengthened our international travel system pretty dramatically over the last month or so.

“We believe that tightening that testing requirement for pre-departure will help catch more potential cases of people who may be positive when they fly into the country and so now is the right time to do it, and we can implement it very quickly.”

On domestic flights, the official added, “the masking requirement is in place already and in fact we will be extending that requirement from January all the way until mid-March”.

The pandemic has killed almost 780,000 people in the US. Nearly 60% of Americans are fully vaccinated. This week the Centers for Disease Control and Prevention (CDC) issued updated guidance recommending that every adult get a booster.