Empty Pfizer COVID-19 vaccine vials will be delivered on Jan.

Paul Hennessy | NurPhoto | Getty Images

The Food and Drug Administration is working to approve the Pfizer and BioNTech Covid-19 vaccine on Monday, the New York Times reported, citing sources.

The review process could go beyond that date, The Times said, as paperwork and negotiations with the company continue.

The move would make it the first vaccine to go from emergency approval to full FDA approval.

The FDA declined to comment on the Times report to CNBC.

U.S. companies have tightened vaccination regulations for employees as Covid cases have increased across the country in recent months, and some cited full FDA approval as part of the decision-making process.

Full FDA approval could also help convince people who are reluctant to get vaccinated until vaccination has been fully approved.

Pfizer and BioNTech began applying for their biologics license for the two-dose vaccine in May after receiving emergency clearance from the FDA last December. The FDA sets a six month target for approval of high priority drugs.

The companies announced Monday that they have begun the approval process for their third booster dose after submitting clinical trial data to the FDA.

If formally approved, Pfizer and BioNTech’s vaccine would remain available in the market after the pandemic ended, and the companies could also promote the vaccine directly to consumers. Pharmaceutical manufacturers with an EUA are banned from promoting their vaccines, CNBC previously reported.

Top health officials from agencies like the Centers for Disease Control and Prevention, the White House, and the FDA said in a statement Wednesday that the effectiveness of mRNA vaccines declines over time, especially for those with compromised immune systems or for everyone who who were vaccinated at the beginning of the vaccine introduction.

According to the CDC, more than 203 million doses of the vaccine have been administered by Pfizer and BioNTech nationwide, fully vaccinating over 91 million people in the United States.

Read the full New York Times report here.