NEW YORK, Dec. 19 (Xinhua) -- New York City's COVID-19 test positivity rate on a seven-day average went up to 6.22 percent, compared with 6.16 percent one day earlier, Mayor Bill de Blasio tweeted on Saturday.

There were 156 new hospitalizations and 2,700 new cases of the coronavirus in the city, said de Blasio, adding that "This weekend we need to double down on what works: practice social distancing, avoid large gatherings, and wear your masks."

On Friday, the mayor tweeted that "more than 11,000 #COVID19 vaccinations have been administered in New York City," while retweeting Health Commissioner Dave A. Chokshi's tweet which said that "NYC is making good progress in vaccinating our health care heroes. Despite the snowstorm, all 44 hospitals slated to receive the #COVID19 vaccine had it delivered and began administering it. So far, 11,152 people have received their first dose."

The same day, New York State's independent Clinical Advisory Task Force approved the American drugmaker Moderna's COVID-19 vaccine, and 346,000 doses of the Moderna vaccine are expected here next week.

Also on Friday, the U.S. Food and Drug Administration (FDA) authorized the Moderna vaccine for emergency use in the United States.

It is the second COVID-19 vaccine that has received FDA's emergency use authorization (EUA) in the country, following the first one developed by American drugmaker Pfizer in partnership with German company BioNTech.

As of Friday evening, coronavirus deaths added up to 24,652 and confirmed cases to 373,884 in NYC, according to The City, a project that tracks the spread of confirmed COVID-19 infections and fatalities in New York City, based on information provided by the New York City Department of Health and Mental Hygiene, the governor's office, The COVID Tracking Project and the Center for Systems Science and Engineering at Johns Hopkins University.