Advisers to the US Food and Drug Administration have voted overwhelmingly to recommend that the agency authorise Novavax's COVID-19 vaccine for use in adults,
The drugmaker hopes the vaccine will become the shot of choice among some American sceptics.
The panel of outside experts voted 21-0 with one abstention in favour of the Novavax dose for those 18 and older after discussing whether the shot's benefits outweigh risks, including rare occurrences of heart inflammation that may be associated with the vaccine.
If the FDA follows the recommendation and authorises the shot, it will be the fourth COVID-19 vaccine available for use in adults in the United States.
The FDA has approved previous shots within days of panel votes, with distribution quickly following.
The timeline for Novavax is not clear.
Novavax Chief Commercial Officer John Trizzino said the agency is still reviewing documents detailing its manufacturing processes submitted last week.
"We hopefully expect to have product in the US in our warehouse by the end of June," he said, adding the company plans to ship millions of doses made by its partner, the Serum Institute of India, soon after authorisation.
Novavax's shot, which is already available in more than 40 countries, including Australia, is a more traditional type of vaccine employing technology that has been used for decades to combat diseases like influenza.
Novavax is hoping to break through to the roughly 27 million US adults who are yet to be vaccinated, particularly those who do not want to receive a vaccine like the Pfizer or Moderna shots based on groundbreaking mRNA technology.
"We do have a problem with vaccine uptake that is very serious in the United States," FDA official Peter Marks told the panel.
"Anything we can do to get people more comfortable to be able to accept these potentially life-saving medical products is something that we feel we are compelled to do."
However, that demand has not materialised in Europe, where Novavax also said it could drive up vaccination among the hesitant.
Around 12.6 million doses of the vaccine have been distributed in the European Union, but only around 220,000 doses of the two-shot inoculation have been administered there since it was launched in December.
Before shots can be administered, the FDA must authorise the vaccine and the Centers for Disease Control and Prevention (CDC) needs to green light its use.
Novavax filed for US authorisation in late January, almost a year behind its original plan, following development and manufacturing problems.