Dr. Soumya Swaminathan, chief scientist at the World Health Organization, urged people to keep practicing public health measures like mask wearing and social distancing while COVID-19 vaccine production scales up enough to reach billions of people worldwide.

"So, we have to be here a little bit patient, the vaccines are going to come, they're going to go to all countries but meanwhile we mustn't forget there are measures that work," Swaminathan said.

People around the world will need to keep practicing fundamental public health measures at least "for the rest of this year at least," according to Swaminathan.

"Even as vaccines start protecting the most vulnerable, we're not going to achieve any levels of population immunity, or herd immunity in 2021," she added.

-ABC News' Christine Theodorou contributed to this report.

President-elect Joe Biden got his second dose of the two-dose Pfizer/BioNTech vaccine on Monday in Newark, Delaware.

After two doses, the Pfizer vaccine is 95% effective.

U.S. Rep. Bonnie Watson Coleman, D-N.J. announced Monday that she has received a positive result for COVID-19 from a rapid antigen test and is awaiting results from a polymerase chain reaction (PCR) test.

Coleman said she was forced to shelter in place with unmasked colleagues last week when a mob of President Donald Trump's supporters stormed the U.S. Capitol building in Washington, D.C.

"Following the events of Wednesday, including sheltering with several colleagues who refused to wear masks, I decided to take a Covid test," Coleman, 75, wrote on Twitter. "I have tested positive."

The congresswoman, who previously received one dose of the Pfizer/BioNTech vaccine, said she is experiencing mild, cold-like symptoms and is isolating at home.

-ABC News' Mariam Khan contributed to this report.

Japan has identified a new variant of COVID-19, Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, said during a Monday news conference.

Japanese health officials alerted the WHO of the new variant, which is different than COVID-19 variants first identified in the U.K. and in South Africa, over the weekend. High transmission of the virus in much of the world is giving it more chances to mutate and evolve into new variants.

"Most notably, transmissibility of some variants of the virus appears to be increasing," Tedros said. "This can drive a surge of cases and hospitalizations, which is highly problematic for health workers and hospitals already close to breaking point," he added.

"At present, the variants do not seem to show increased severity of disease," Tedros said.

-ABC News' Christine Theodorou contributed to this report.

Weeks after video emerged of mostly maskless partygoers at U.S. President Donald Trump's Mar-a-Lago Club in Palm Beach, county officials are cracking down.

Palm Beach County sent a letter this week, acquired by ABC News, warning the club and saying officials had met with representatives from the club about violations. Masks are mandatory in the county in all businesses or establishments, and anywhere in public social distancing cannot be maintained. The mandate is currently in place through Jan. 20 -- the same day the county's most famous resident will be exiting the White House.

"Thank you for meeting with us last week to discuss the concerning allegations regarding the Mar a Lago New Year's Eve party and lack of facial coverings being worn during evening activities," the county wrote in the letter addressed to Bernd Lembcke, executive vice president and managing director of Mar-a-Lago Club.

"We recount that you provided masks for all party goers who attended the party and that you provided additional masks for those that walked from the reception area to the main dining ballroom," the letter continued. "Although you provided these important steps, it seemed that based on the video evidence, there was a breakdown in enforcement of the mask orders that led to almost the entire room of guests being without masks during the later evening activities."

The letter also includes a confirmation of the violation, which is a first-time warning, that lays out a fine of up to $15,000 for each potential future violation.

Trump has consistently downplayed wearing masks over the course of the entire pandemic. Despite telling people to wear masks on occasion at official briefings, he also mocked others for wearing them, including President-elect Joe Biden. Many supporters have decried mandates and openly flouted rules, including maskless Trump supporters who stormed the Capitol last week.

ABC News' Will Gretsky contributed to this report.