Moderna should have enough data from its late-stage trial to know whether its coronavirus vaccine works in November, CEO Stephane Bancel said Thursday.
The company could have enough data by October, but that's unlikely, Bancel said during an interview on CNBC's "Squawk Box."
"If the infection rate in the country were to slow down in the next weeks, it could potentially be pushed out in a worst-case scenario in December," he added.
Moderna's experimental vaccine contains genetic material called messenger RNA, or mRNA, which scientists hope provokes the immune system to fight the virus. In July, the company released early-stage data that showed its potential vaccine generated a promising immune response in a small group of patients.
Bancel's comment came four days after the CEO of Pfizer said its vaccine could be distributed to Americans before the end of the year. CEO Albert Bourla told CBS' "Face the Nation" that the company should have key data from its late-stage trial for the Food and Drug Administration by the end of October. If the FDA approves the vaccine, the company is prepared to distribute "hundreds of thousands of doses," he said.
It also comes as infectious disease experts and scientists in recent weeks have said they have concerns that the White House may be pressuring the FDA to approve a vaccine before it's been adequately tested. On Wednesday, President Donald Trump said the U.S. government could start distributing a coronavirus vaccine as early as October, a much more optimistic estimate than his own health officials have publicly advised.
He said the U.S. has manufactured all of the necessary supplies and health officials will be able to distribute at least 100 million vaccine doses by the end of the year. The vaccine could be distributed starting in October or November, but he said "I don't think it's going to be too much later than that."
"We're very close to that vaccine as you know and I think much closer than I think most people want to say," Trump said during a White House press briefing. "We think we can start some time in October. So as soon as it's announced we'll be able to start. That will be from mid-October on. It may be a little bit later than that."
On Sept. 8, nine drug companies, including Moderna, released a letter pledging that they would prioritize safety and uphold " the integrity of the scientific process" in their efforts to develop coronavirus vaccines.
And on Thursday, Moderna released details on how its study will be evaluated.
"We believe this is unprecedented times. There's a lot of suffering from a public health standpoint," Bancel said Thursday. "If Moderna's vaccine were to get a good safety readout and a good efficacy readout and be approved by the agency, we care deeply that this vaccine is trusted."
Earlier this month, Moderna announced it was slowing enrollment slightly in its clinical trial to ensure it has sufficient representation of minorities most at risk for the disease.
The company so far has enrolled 25,296 people in the trial and expects to enroll up to 30,000 participants.