Being vaccinated against COVID-19 will not be a requirement to compete in the upcoming Tokyo Olympics, organizers said Thursday.

The 2020 Summer Olympics were supposed to kick off in the Japanese capital last year on July 24. But in late March, amid mounting calls to delay or cancel the upcoming Games, the International Olympic Committee (IOC) and Japan’s prime minister announced that the event would be held a year later due to the coronavirus pandemic.

The Games are now scheduled to open in Tokyo this summer on July 23, but doubt has surfaced as Japan — and much of the world — grapples with a resurgence of COVID-19 infections. Moreover, Japan is not expected to begin administering its first round of COVID-19 vaccinations until the end of February.

During a press briefing Thursday following a call with the IOC's president, organizers were asked how Japan will safely host the Olympics as scheduled when the country's mass vaccination campaign is not expected to inoculate most of the population by that date.

"Since last year, we have been having thorough debates and discussions on that topic. We do not consider the vaccine as a prerequisite," Toshiro Muto, chief executive officer of the Tokyo 2020 organizing committee, told reporters. "Of course, it's desirable to have as many people as possible vaccinated, and that would bring about positive benefit. But even if vaccination is not done, we will be able to hold the Games."

Muto added that COVID-19 vaccinations would be administered to athletes but it wouldn't be an obligation.

As for vaccinating staff and volunteers, Muto said that decision will be made at the national government level.

Yoshiro Mori, president of the Tokyo 2020 organizing committee, said they are still considering holding the Games without spectators.

“One option among many would be to hold the games without spectators," he told reporters. "We don’t want to do this but we must take this scenario into consideration."

With less than six months left until the opening day, a recent poll by Japanese news agency Kyodo found that around 80% of people in Japan believe the Tokyo Olympics should not be held this summer. When asked by ABC News about that opinion, Mori said: "There is a balance. On one hand there is criticism, the other hand is support."

Mori noted that the IOC's president has "strongly backed up our efforts" to hold the Tokyo Olympics as planned.

"Nowhere did we hear objections or doubt," he told reporters. "Everyone wants to successful hold the games."

ABC News' Anthony Trotter and Karson Yiu contributed to this report.

British Prime Minister Boris Johnson has indicated that England's lockdown restrictions will remain in place until at least early March.

In a statement to lawmakers at the U.K. House of Commons on Wednesday, Johnson said officials "do not yet have enough data to know exactly how soon it will be safe to reopen our society and economy." But he expressed hope that schools could reopen from March 8, so long as his government meets its target of vaccinating everyone in the top four priority groups by mid-February.

The prime minister also announced new restrictions for travelers arriving in England from countries deemed to be high-risk. He said the United Kingdom remains in a "perilous situation" with more than 37,000 people hospitalized with COVID-19 -- almost double the amount during the previous peak in April.

During a press conference later Wednesday, Johnson told reporters that March 8 was the "earliest" date by which the government could "responsibly" allow schoolchildren to return to classrooms.

The comments come after the U.K. became the fifth country in the world to record more than 100,000 deaths from COVID-19.

England entered its third national lockdown of the coronavirus pandemic on Jan. 5.

Although Johnson is the prime minister of the U.K., his administration is only responsible for COVID-19 restrictions in England because public health legislation is devolved to national governments within the U.K., meaning that Scotland, Wales and Northern Ireland are responsible for their own coronavirus-related policies.

A new, more contagious variant of the novel coronavirus first identified in the United Kingdom has been detected in Alabama for the first time.

The Alabama Department of Public Health announced Wednesday that two cases of the variant were confirmed in Montgomery County residents and a third in a Jefferson County resident. Two of the patients are children under the age of 19.

"These are the first reported cases in Alabama of the variant which was first detected in the United Kingdom in late 2020," the department said in a statement. "This variant is associated with increased person-to-person transmission of COVID-19. ADPH is closely monitoring the emergence of this variant which has been detected in at least 24 other states."

The so-called B117 variant, which is believed to have emerged in England in September, has been detected in more than two dozen U.S. states.

The U.S. Centers for Disease Control and Prevention now projects that the country will have recorded up to 514,000 COVID-19 deaths by Feb. 20.

The CDC on Wednesday published its latest national ensemble forecast, which predicts that the country's COVID-19 death rate will likely decrease over the next four weeks and that 13,500 to 25,000 new fatalities from the disease will likely be reported in the week ending Feb. 20. A total of 479,000 to 514,000 COVID-19 deaths are projected to be reported nationwide by this date.

Last week’s national ensemble forecast predicted there would be a total of 465,000 to 508,000 COVID-19 deaths reported nationwide by Feb. 13.

ABC News' Ahmad Hemingway contributed to this report.