Georgia has detected a case of the new coronavirus variant known B.1.1.7, which was first identified in the United Kingdom, state health officials announced Tuesday.

The patient is an 18-year-old man with no travel history, who is currently isolated at home.

"The emergence of this variant in our state should be a wake-up call for all Georgians," Dr. Katheen Toomey, commissioner of the Georgia Department of Public Health, said in a statement on Tuesday. "Even as we begin roll out of a COVID-19 vaccine, we must not let down our guard and ignore basic prevention measures -- wear a mask, social distance and wash your hands frequently."

While preliminary evidence suggests that the new variant is more contagious than the old one, it is not believed to cause more severe illness or to be more deadly. Cases of the new variant have also been detected in Colorado, California, Florida and New York.

-ABC News' Brian Hartman contributed to this report.

After the Food and Drug Administration issued a warning on Monday that COVID-19 tests produced by the company Curative carry the risk of "false negative results," attending physician of the U.S. Congress Dr. Brian Monahan sent a memo notifying Capitol Hill employees that the Capitol's testing system uses Curative tests.

In the Jan. 4 memo obtained by ABC News, Monahan described the Curative test as "the most accurate available" according to information he'd received to date and noted that the risk of a false negative "is a problem for all coronavirus tests."

"The FDA notice does not raise any doubts about the accuracy of a positive test result," Monahan added. "We expect to have additional information in the coming days from the FDA and our expert consultants with regard to any concerns about the ongoing use of this test for the Capitol community."

-ABC News' Mariam Khan and Anne Flaherty contributed to this report.

The Strategic Advisory Group of Experts (SAGE), an advisory group to the World Health Organization, updated its guidance for the Pfizer/BioNTech COVID-19 vaccine Tuesday.

SAGE's recommendations to the WHO director-general, who will ultimately decide whether to approve them, included recommending two doses of the Pfizer vaccine within 21-28 days, with provisions made for countries in extraordinary circumstances.

The group also recommended that that vaccine only be given in settings where allergic reactions can be treated. Since there's not yet enough safety data available on pregnant women, the group only recommends the vaccine for pregnant women in settings where benefits outweigh risks, such as for pregnant health care workers who are exposed to the virus.

People who have had COVID-19 and recovered should get vaccinated, according to SAGE.

"We are in a race to save lives right now," Dr. Tedros Adhanom Ghebreyesus, director-general of the World Health Organization, said Tuesday. "Caseloads are so high in several countries that hospitals and intensive care units are filling up to dangerous levels."

"New variants, which appear to be more transmissible, are exacerbating the situation," Tedros added.

-ABC News' Christine Theodorou contributed to this report.

A third of health workers in the New York City public hospital system declined COVID-19 vaccines, Mayor Bill de Blasio said Tuesday, as he tried to explain the city-run hospitals' lagging vaccination numbers.

"It's a real issue and we've got to look it in the eye," de Blasio said. "It's understandable that after all the pain of 2020 a lot of people are worried and in general folks have been through so much. We’ve got to understand. We’ve got to win trust for the vaccine."

The mayor also pushed back on Gov. Andrew Cuomo's threat to fine hospitals that fail to use their vaccine allotment within seven days.

"They don’t need the threat of fines," de Blasio said. "If the state of New York says, you get [a] $1 million fine if you move too quickly and [a] $100,000 fine if you move too slowly, that doesn’t get anyone anywhere."

-ABC News' Aaron Katersky contributed to this report.