As the U.S. embarked on a historic mass immunization effort last week against the novel coronavirus with the recently authorized Pfizer-BioNTech COVID-19 vaccine, and now Moderna, a top White House official is urging recipients to continue mitigation measures.

Health and Human Services Secretary Alex Azar told Fox & Friends co-hosts Tuesday that scientists are still working to confirm whether individuals inoculated against COVID-19 still need to wear masks and keep up with social distancing after receiving the shot.

Health and Human Services Secretary Alex Azar speaks during a news conference in the briefing room at the White House in Washington, Friday, Nov. 20, 2020. (AP Photo/Susan Walsh)

Health and Human Services Secretary Alex Azar speaks during a news conference in the briefing room at the White House in Washington, Friday, Nov. 20, 2020. (AP Photo/Susan Walsh)

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"We’re still studying some fundamental scientific questions though, such as, once you’ve been vaccinated, do you still need to wear a mask to protect others, could you still be carrying the virus even though you’re protected from it?" he said.

Azar said the current consensus is to mask up and practice social distancing while the matter undergoes investigation.

"If you’re getting vaccinated right now, still social distance, still wear a mask, but all these have to be data and science-driven, so we’re working to generate the data there so that as we go forward, we’ll be able to advise people on a foundation of data," Azar continued.

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The initial wave of Pfizer’s COVID-19 vaccines that blanketed the U.S. last week went into the arms of at-risk, front-line medical workers, residents of nursing homes and some government officials. The first wave of the newly authorized Moderna COVID-19 vaccine began rollout this week, and vaccinations started Monday.

An independent advisory panel to the Centers for Disease Control and Prevention has voted to recommend the next wave of vaccines go to front-line, essential workers and people over the age of 75. 

Azar's comments came shortly before he joins Dr. Anthony Fauci, the nation's leading infectious disease expert, among others, to receive Moderna's COVID-19 vaccine Tuesday morning at 10 a.m. ET.

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Of note, the primary goal of Pfizer's and Moderna’s COVID-19 vaccines in clinical trials was to prevent COVID-19 disease, and it was not immediately clear what level of protection the vaccines offered against transmission or virus spread.

When the drug sponsors sought emergency authorization from the U.S. Food and Drug Administration, the agency deemed the products safe and effective but was careful to note limited data over the transmission of SARS-CoV-2, the virus causing COVID-19 disease, which necessitated further investigation.

Inoculated individuals aside, health officials continue to urge the public to wear masks, socially distance, avoid crowds and practice hand hygiene to slow virus spread amid persistent surges in cases, hospitalizations and deaths.