COVID-19 updates: US has 1st day since November with fewer than 100K new cases

Andrew Yang, who ran for president of the United States in 2020 and is currently running to be mayor of New York City, has tested positive for COVID-19.

"After testing negative as recently as this weekend, today I took a COVID rapid test and received a positive result," Yang said in a statement through his campaign Tuesday.

Yang said he has mild symptoms and that, as he self-quarantines at home, he'll "continue to attend as many virtual events as possible."

"Our team has begun the contact tracing process to notify anyone who may have been in close contact with me," he added.

Spanish professional soccer club Real Madrid announced Tuesday that its president has tested positive for COVID-19.

Florentino Perez, 73, returned a positive result during the Madrid-based club's routine testing. He is not showing any symptoms, the club said in a brief statement.

No additional details were provided by the club.

Results from a late-stage clinical trial of Russia's flagship coronavirus vaccine show the shot is not only safe but also 91.6% effective against symptomatic COVID-19, according to a study published Tuesday by the peer-reviewed medical journal The Lancet.

The randomized, double-blinded, placebo-controlled Phase 3 trial in Moscow involved 19,866 adult participants, of whom 14,964 received the vaccine, called Sputnik V, and 4,902 received a placebo. The two-dose vaccine was administered 21 days apart.

There were 62 confirmed cases of COVID-19 identified among the trial participants in the placebo group and 16 cases in the vaccine group, according to the study.

The study said there were no serious adverse effects related to the vaccine recorded during the trial and that 94% were mild, including flu-like symptoms, pain at the injection site and headaches.

A sub-analysis of 2,144 trial participants older than 60 showed the vaccine had a similar efficacy of 91.8%, according to the study.

"Our interim analysis of this phase 3 trial of Gam-COVID-Vac has shown promising results," the researchers wrote.

The publication of peer-reviewed data follows last year's criticism of Russia for registering the COVID-19 vaccine -- and declaring itself the first country in the world to do so -- before starting crucial Phase 3 trials.

"The development of the Sputnik V vaccine has been criticised for unseemly haste, corner cutting, and an absence of transparency," Ian Jones, a professor of virology at England's University of Reading, wrote in a comment piece published Tuesday by The Lancet alongside the study. "But the outcome reported here is clear and the scientific principle of vaccination is demonstrated, which means another vaccine can now join the fight to reduce the incidence of COVID-19."

Russia’s Direct Investment Fund (RDF), which funded the production of Sputnik V and is responsible for its worldwide marketing, hailed the study and noted that the COVID-19 vaccine is currently one of only three in the world with an efficacy above 90%. The vaccine, which is now registered in 16 countries, costs $10 per dose and can be stored and transported more easily because it can be kept at the temperature of a standard refrigerator, according to RDF.

"The data published by The Lancet proves that not only Sputnik V is the world’s first registered vaccine, but also one of the best," Kirill Dmitriev, CEO of RDF, said in a statement Tuesday.

ABC News' Patrick Reevell contributed to this report.

Japanese Prime Minister Yoshihide Suga has extended a state of emergency in Tokyo and nine surrounding prefectures for another month to further stem the spread of the novel coronavirus.

The declaration, however, was lifted in Tochigi prefecture, north of Tokyo, where the COVID-19 infection rate has eased.

"I regret that the declaration cannot be lifted across the nation at this time," Suga said Tuesday night in a televised address from his office in Tokyo.

The prime minister used a chart to show that Japan's daily number of newly diagnosed infections has declined from 7,721 on Jan. 7 to 1,783 on Feb. In Tokyo, that number has dropped from 2,447 on Jan. 7 to 393 on Feb. 1. According to the Japanese Ministry of Health, Labor and Welfare, there were 556 new cases of COVID-19 confirmed in the capital city on Tuesday.

Suga said the state of emergency could be lifted earlier than March 7 if the situation continues to improve. He noted that his government is hoping to begin a mass COVID-19 vaccination program as early as mid-February.

"Thanks to the cooperation of the people of Japan, we have seen a marked outcome," he said. "At this point in time, I need to ask the people to endure another round of the state of emergency so that positive outcomes can be solidified."

The move comes less than six months before the pandemic-delayed 2020 Summer Olympics are scheduled to open in Tokyo.

A state of emergency declaration gives the governors of those respective regions the authority to ask residents for cooperation in efforts to curb the spread of the virus. There are currently no legal ramifications for non-compliance.

Suga first declared a state of emergency in Tokyo and three neighboring prefectures on Jan. 7, before expanding the order to include more virus-hit areas.

Under the state of emergency, Suga said governors will ask residents to refrain from dining out and to stay home after 8 p.m. unless for essential reasons. They will also ask companies to decrease the number of employees commuting to work by 70%.

Suga said bars and restaurants will be asked to stop serving alcohol by 7 p.m. and to close by 8 p.m. Governors may disclose the name of the businesses that don't comply, while those that do will be given 1.8 million Japanese yen ($17,000) per month.

Spectator events will be limited to an audience of 5,000 people. Schools will not be asked to close, according to Suga.

Suga's predecessor, Shinzo Abe, declared a nationwide state of emergency relatively early in the pandemic in April, which lasted for a month. At that time, residents were asked to reduce person-to-person contact by 80% and to practice "jishuku," or "self-restraint," by staying at home and closing non-essential businesses.

As of Tuesday, the Japanese Ministry of Health, Labor and Welfare has confirmed 392,475 cases of COVID-19 since the start of the pandemic, including 5,846 deaths.

ABC News' Anthony Trotter contributed to this report.