Coronavirus updates: Herd immunity by fall 'ambitious,' says surgeon general nominee

British Health Secretary Matt Hancock announced Tuesday that he will be self-isolating at home for the rest of the week.

Hancock said he was pinged by the U.K. National Health Service's COVID-19 app on Monday night, alerting him that he had been in "close contact" with someone who has tested positive.

"So that means I'll be self-isolating at home, not leaving the house at all until Sunday," Hancock said in a video statement posted on Twitter. "This self-isolation is perhaps the most important part of all the social distancing, because I know from the app that I've been in close contact with someone who has tested positive and this is how we break the chains of transmission."

"So you must follow these rules, like I'm going to," he continued. "I've got to work from home for the next six days and together, by doing this, by following this and all the other panoply of rules that we've had to put in place, we can get through this is and beat this virus."

Hancock recently came under fire by British tabloids after he was seen in a crowded park in north London on Saturday. The current lockdown restrictions in England bars people from leaving their homes except for a very limited set of exemptions, including to shop for basic necessities, outdoor exercise and to go to work if they cannot do so from home. A photograph of Hancock surfaced after British Boris Johnson had released a video urging people to "think twice" before leaving their homes this weekend.

Norway's national public health institute said Tuesday that there is currently no correlation between receiving the Pfizer/BioNTech vaccine and an increased risk of death among 23 people who died after getting the shot.

The deceased were "severely frail patients" who died within six days after vaccination in the Scandinavian country, and the incidents "do not imply a casual relationship between COVID-19 vaccination and death," according to Dr. Sara Viksmoen Watle, chief physician at the Norwegian Institute for Public Health.

"When we vaccinate the eldest and sickest who often have several underlying conditions we expect high mortality in this population. Hence, we also expect deaths following vaccination," Watle said in a statement Tuesday. "We do not yet know if these deaths are due to the vaccine or other causes, but we cannot exclude that common side effects may have led to a more severe course for some patients."

The Norwegian Medicines Agency and the Norwegian Institute of Public Health are investigating the deaths.

"So far, there are no statistical analyses that indicate that coronavirus vaccination has had an increased risk of death among those vaccinated," Watle said, after noting that the fatal incidents will be examined "in relation to the expected number of deaths among the nursing home population."

"In order to be able to interpret this information, it is important to see the full picture," she added. "Nursing home residents are at very high risk of a severe disease course or dying from COVID-19, and have therefore been prioritised for vaccination. A large proportion of those who live in nursing homes have severe underlying conditions or are in the last stages of life. Life expectancy in nursing homes is relatively short and on average, more than 300 people die in Norwegian nursing homes every week."

U.S. President-elect Joe Biden's pick to lead the Centers for Disease Control and Prevention said she will "hit the ground running" and suggested there might be more travel restrictions in store.

"We need to reset the stage here. We need to make sure the country, the people understand that this pandemic is now going to be addressed with science, with trust, with transparency, with communication of exactly where we are to the American people," Dr. Rochelle Walensky told ABC News chief anchor George Stephanopoulos in an interview Tuesday on "Good Morning America."

Walensky, the chief of infectious diseases at Massachusetts General Hospital in Boston and a professor of medicine at Harvard Medical School, will be sworn in Wednesday as director of the CDC -- an appointment that does not require Senate confirmation.

"I will be sworn in tomorrow, but the work has been happening since I was named," Walensky said, "and we've been working really hard to make sure we can come in and hit the ground running and make sure that we can get this country back to health."

Walensky said the incoming administration's plan to vaccinate 100 million people against COVID-19 within the first 100 days of Biden's presidency is "really ambitious but doable." The key is making sure there are enough people on the ground to administer the vaccines, understanding the supply and how many doses are going to which states, and making vaccines accessible to all people.

"All of that plan is underpinned with equity," Walensky said. "We need to make sure that we're equally and equitably getting the vaccine across this country."

In one of his last orders, outgoing President Donald Trump announced Monday night that he was rescinding entry bans imposed because of the coronavirus pandemic on most visitors from Brazil, the United Kingdom and much of Europe effective Jan. 26. However, Biden's incoming White House press secretary, Jen Psaki, said the new administration won't be lifting the bans.

Walensky agreed with the move to reject Trump's proclamation and said there may be more travel restrictions introduced.

"If you look at the fatalities of 400,000 that we're likely to hit today, if you look at our cases across this country, I don't think now is the time to encourage people to get on international fights, to encourage people to mobilize," Walensky said. "I think now is the time to really buckle down, double down our efforts. And so I don't expect that we'll be lifting travel restrictions and, if anything, I think we can expect that they might tighten, especially in the context of variants that we're hearing about."

Israel confirmed 10,222 new cases of COVID-19 on Monday, its highest daily tally since the pandemic began, suggesting the country's mass vaccination campaign hasn't kicked in yet.

The record figure translates to a nationwide positivity rate in COVID-19 tests of 10.2% However, one promising sign is that the number of critically ill patients hospitalized with COVID-19 across Israel has remained steady over the past few days.

Israel's cumulative totals now stand at 562,167 confirmed cases and 4,049 deaths from the disease, according to the latest data from the Israeli Ministry of Health.

Official figures show 25% of Israel's general population -- nearly 2.2 million people -- have received the first of two doses of a COVID-19 vaccine, while 5% -- more than 420,000 -- have received their second dose.

The Israeli government is expected to meet Tuesday afternoon to determine whether to extend the current lockdown, which has been in place since Jan. 8 and is slated to end Jan. 21.

ABC News' Bruno Nota contributed to this report.