As COVID-19 infections rise worldwide, pharmaceutical companies working on coronavirus vaccines have floated promising — and sometimes aggressive — timelines for regulatory approval.

However, it’s highly unlikely that any treatment will see the light of day in 2020, given that the availability of those currently under development will be dedicated solely to emergency use.

Hopes for an effective treatment are building alongside expectations that more states can gradually relax the stay-at-home orders decimating the economy. Yet in a Senate hearing this week, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), reiterated his belief that a vaccine in time for the Fall school term is unlikely.

Back in March, Fauci said that, at best, the industry will find a “signal of efficacy” by the fall.

”And an efficacy signal means that even though you haven’t definitively proven that a vaccine works, you get enough information that if it were an emergency, you might be able to have an emergency use authorization for it,” Fauci said at a March 31 briefing.

On Friday, President Donald Trump on Friday unveiled Operation Warp Speed, an initiative to “finish developing, and then manufacture and distribute, a proven coronavirus vaccine” expeditiously, perhaps by year’s end.

Still, even with dozens of companies furiously at work on a vaccine, health care professionals say 2021 is the more reasonable timeframe — and that’s if everything goes perfectly.

“We’ve never seen everything go perfectly,” said Dr. Rick Bright, the whistle-blowing former BARDA director who was in charge of developing vaccines for the coronavirus.

“I think it’s going to take a lot longer than that,” he told a Congressional hearing on Wednesday. In addition, production remains a major concern.

“Normally it takes up to 10 years to make a vaccine. We’ve done it faster in emergency situations...when we had starting material in the freezer for Ebola,” Bright added. “But for a novel virus, it actually hasn’t been done quickly.”

‘No one company’ to produce billions of doses

The breakthrough success of Gilead Sciences’s (GILD) remdisivir, an experimental antiviral treatment that’s receiving emergency use authorization from the FDA, is an example of why expectations for an accelerated timeline for a vaccine are so problematic.

In Gilead’s case, there are only 1.5 million doses available, which the company has pledged to donate. However, the distribution plan has already run into trouble, with some states and hospitals left empty-handed amid a confusing prioritization method.