Pope Francis and his predecessor, Pope Emeritus Benedict XVI, have received their first dose of a COVID-19 vaccine, according to Vatican spokesman Matteo Bruni.

"I can confirm that as part of the Vatican City State vaccination program to date, the first dose of the COVID-19 vaccine has been administered to Pope Francis and the Pope Emeritus," Bruni said in a statement Thursday.

Francis, who turned 84 last month and had part of a lung removed when he was younger, reportedly received the shot Wednesday while Benedict, 93, reportedly got it Thursday.

Vatican City, an independent enclave surrounded by Rome that serves as the headquarters of the Roman Catholic Church, launched the immunization campaign on Wednesday, administering doses of a COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech.

The tiny city-state has a population of only around 800 people but employs more than 4,000. It's unclear how many doses of the Pfizer/BioNTech vaccine have been procured so far.

Vatican City citizens, along with employees and pensioners, will have the opportunity to receive the vaccine as well as family members who are entitled to use of the city-state's health care system. Priority is being given to health care workers, public safety personnel, the elderly and individuals who are most frequently in contact with the public, according to Bruni.

The vaccination campaign is voluntary and people under the age of 18 are being excluded for the time being, Bruni said.

Since the start of the pandemic, Vatican City has reported at least 27 confirmed cases of COVID-19, according to a real-time count kept by Johns Hopkins University.

ABC News' Phoebe Natanson contributed to this report.

There were 229,610 new cases of COVID-19 confirmed in the United States on Wednesday, according to a real-time count kept by Johns Hopkins University.

It's the ninth straight day that the country has reported more than 200,000 new cases. Wednesday's tally is less than the country's all-time high of 302,506 newly confirmed infections on Jan. 2, Johns Hopkins data shows.

An additional 3,959 new deaths from COVID-19 were registered nationwide on Wednesday, down from a peak of 4,327 fatalities logged the previous day, according to Johns Hopkins data.

COVID-19 data may be skewed due to possible lags in reporting over the holidays followed by a potentially very large backlog.

A total of 23,079,163 people in the U.S. have been diagnosed with COVID-19 since the pandemic began, and at least 384,794 have died, according to Johns Hopkins data. The cases include people from all 50 U.S. states, Washington, D.C., and other U.S. territories as well as repatriated citizens.

Much of the country was under lockdown by the end of March as the first wave of pandemic hit. By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up over the summer.

The numbers lingered around 40,000 to 50,000 from mid-August through early October before surging again to record levels, crossing 100,000 for the first time on Nov. 4, then reaching 200,000 on Nov. 27 before topping 300,000 on Jan. 2.

U.S. Rep. Adriano Espaillat, D-N.Y., announced Thursday that he has tested positive for COVID-19, one day after attending the impeachment vote on the House floor.

Espaillat said he is following guidance from his physician and is quarantining at home.

"I received the second dose of the #COVID19vaccine last week and understand the affects take time," Espaillat wrote on Twitter. "I have continued to be tested regularly, wear my mask and follow the recommended guidelines."

Eight lawmakers have tested positive for COVID-19 since the Jan. 6 siege on the U.S. Capitol building in Washington, D.C.

ABC News’ Ben Siegel contributed to this report.

An international team of 13 scientists researching the origins of COVID-19 arrived Thursday in Wuhan, China, where the novel coronavirus was first discovered, according to the World Health Organization.

"The experts will begin their work immediately during the 2 weeks quarantine protocol for international travelers," the WHO wrote on Twitter.

All team members had to be tested for COVID-19 again in Singapore before flying to China. The polymerase chain reaction (PCR) tests were all negative, but two IgM antibody tests returned positive results. Those two scientists remain in Singapore as they are retested, according to the WHO.