The Food and Drug Administration’s independent advisory committee will meet in open session on Friday to review the most recent data submitted by Pfizer and discuss whether a booster dose is safe enough for widespread use and whether it is necessary and effective in improving COVID-19 protection levels.

Their vote will be non-binding; the FDA is not required to follow the recommendations of the Vaccines and Related Biological Products Advisory Committee (VRBPAC), but they usually do.

Following that vote, the FDA will decide whether to formally amend Pfizer’s current vaccine approval. Next week, the matter will be heard by the Centers for Disease Control and Prevention’s independent advisory panel (ACIP), which will decide who should get a booster shot and when. The director of the CDC will then formally approve whatever ACIP recommends.

The FDA will make an opening statement at 8:30 a.m. ET on Friday, followed by presentations from CDC representatives, a discussion about booster protection, and a presentation from Pfizer executives who will make the case for why boosters are appropriate.

The committee will debate the issue for about two hours after a public hearing portion in the afternoon and a question-and-answer session on both Pfizer’s and the FDA’s presentations. If everything goes as planned, the vote will take place around 4:45 p.m. ET.

The meeting on Friday comes amid a heated debate over the timeline for boosters, with some health experts claiming that the data and timing are still too early.

On Monday, two top FDA officials who are leaving the agency later this year publicly waded into the debate, separating from the agency and arguing in a scientific journal that it was too soon to give booster shots to the general public because the vaccines still offer strong protection against serious disease.

Both are expected to attend the discussion on Friday. One of them, the director of the FDA’s office of vaccine research and review, is supposed to provide an overview of the topic for the FDA at the start of the day. Dr. Sharon Alroy Preis, the head of Israel’s public health services, is also scheduled to present data on booster protection against COVID infection and severe disease at the meeting on Friday.

The FDA appeared unconvinced about the need for boosters in a review of Pfizer’s data, which was also released on Wednesday. The FDA stated that Pfizer’s efficacy data could be hampered by the limitations of studying boosters in real-world situations, which can introduce complicating factors.

“There are many potentially relevant studies,” the FDA wrote in its briefing. “However, FDA has not independently reviewed or verified the underlying data or their conclusions.”

Without naming anyone, but acknowledging those lingering concerns, Pfizer CEO Albert Bourla penned an open letter on Thursday arguing for booster shots.

“This week, we are approaching another critical juncture in our ongoing battle against the virus,” Bourla writes of Friday’s FDA advisory committee meeting. “Since the beginning of this pandemic, Pfizer and BioNTech have pledged to follow the science and keep the public updated on our progress in order to help put an end to this global health crisis. We have adhered to our commitment to full transparency by not cherry-picking data.”