COVID-19 vaccine timelines hinge on how trials, FDA approvals work


With several potential COVID-19 vaccines in their final phase of study, the anticipation is building about when one could be approved and available.

Several frontrunners, including candidates from Moderna, Pfizer, AstraZeneca and Johnson & Johnson, are currently undergoing large-scale human trials with tens of thousands of subjects.

Health officials have been unable to say with certainty when the country could see a vaccine, though some have suggested it’s possible one could be ready by the end of the year.

But when the doses could become available to the public will hinge on approval from the Food and Drug Administration.

Here are some of the vaccines that could soon be ready to evaluated by the FDA and what that process would look like:

COVID-19 vaccine updates

These are some of the vaccines candidates making the most progress so far:


Moderna began Phase 3 of its trial on July 27, and then enrolled about 15,000 participants a month later.

The trial is designed for people to receive a second shot either three or four weeks later.

Moderna president Stephen Hoge said earlier this month that over 25,000 of the 30,000 planned participants have enrolled in the trial, CBS News reported.

But with two months of follow-ups factored into the study, it’s unlikely the company would have enough data before November.


Pfizer entered Phase 3 of trials on the same day as Moderna and has followed a nearly identical timeline.

The company announced earlier this month that it would expand its study from 30,000 to 44,000 people to include teenagers, as well as people with diseases such as HIV and hepatitis A, B or C.

But CEO Albert Bourla said the expansion occurred because the vaccine appeared extremely safe, and it’s not expected to impact the timeline for completion.

A report on the safety and effectiveness should available for regulators by the end of October.

Bourla said the company has already begun to manufacture doses so the vaccine “will be ready” once it gets approved by the FDA, USA Today reported.


AstraZeneca temporarily halted its global trial that it was running with Oxford University earlier this month after one participant suffered what may have been a serious adverse reaction.

The company resumed testing days later at other international sites, but the study remains on hold in the US as regulators probe safety concerns.

Johnson & Johnson

Johnson & Johnson began administering doses last week to up to 60,000 candidates in what’s expected to be the largest US trial.

Though the final-stage trials come months after competitors, the vaccine would only require one dose as opposed to two.

If enrollment goes as expected, results could come from the trial as soon as the end of the year, allowing the company to seek approval early next year, the company said.

When will a COVID-19 vaccine be ready in the US?

Though no one can say for sure, the Trump administration and leading health officials have offered their predictions on the vaccine’s timeline.

President Trump has said that a successful candidate could be ready as soon as October, saying that Americans “could have a very big surprise coming up.”