Trial will include administering two doses of vaccine within 28 days to 3,000 children aged 12 to 17.
Moderna’s COVID-19 vaccine appeared to be set for regulatory authorisation this week after US Food and Drug Administration (FDA) staff members did not raise any major new concerns about it in documents released on Tuesday.
The FDA reviewers said a two-dose regimen of Moderna’s vaccine was highly effective in preventing confirmed cases of COVID-19 and did not raise any specific safety issues with using the vaccine in adults over the age of 18.
The comments were made in documents prepared for Thursday’s meeting of outside experts, who will discuss whether to endorse a US emergency use authorisation (EUA) for the Moderna shot.
The FDA typically follows the advice of the panel but is not required to do so.
Moderna’s is the second vaccine the FDA has considered, behind one from Pfizer and Germany’s BioNTech, which was authorised last week.
Hospitals began giving the Pfizer shots on Monday and the United States is counting on the Moderna vaccine to fulfil its promise to inoculate 20 million people this month.
Packed in dry ice to stay at ultra-frozen temperatures, shipments of Pfizer’s COVID-19 vaccine is expected to arrive at 400 additional hospitals and other distribution sites on Tuesday, one day after the nation’s death toll surpassed a staggering 300,000. The first three million shots are being strictly rationed to front-line healthcare workers and elder-care patients, with hundreds of millions more shots needed over the coming months to protect most Americans.
A second vaccine cannot come soon enough as the country’s daily death count continues to top 2,400 amid more than 210,000 new daily cases, based on weekly averages of data compiled by Johns Hopkins University. The devastating toll is only expected to grow in coming weeks, heightened by holiday travel, family gatherings and lax adherence to basic public health measures.
The first vaccine deliveries have provided a measure of encouragement to exhausted doctors, nurses and hospital staffers around the country.
The FDA said there appeared to be some protection for trial participants after the first dose of Moderna’s vaccine, which is given in two shots, with 28 days between inoculations, but there was not enough information on longer-term protection.
It said vaccine efficacy was 80.2 percent in participants who only received one dose at the time of the interim analysis, which was based on data collected as of November 7.
They said serious side effects in the trial of the vaccine represented medical events that occur in the general population at a similar frequency as observed in the study.
The FDA did flag the possibility that the vaccine was contributing to Bell’s palsy, a type of facial paralysis also reported by participants in the Pfizer trial.
Moderna reported four cases of Bell’s palsy, including three among people who had the vaccine and one in the placebo group. The company said three of the cases had resolved itself.
Although the FDA said the trial participants with Bell’s palsy had predisposing factors, the “potential contribution of the vaccine to the manifestations of these events of facial palsy cannot be ruled out”.
Pfizer reported six cases of Bell’s palsy, including four in the vaccine arm, which it said was a rate typical of the general population.