The first interim analysis of the vaccine’s efficacy will happen when 53 people in the entire study get symptomatic Covid-19, the report said.

“That first analysis is likely to occur in November, but it’s hard to predict exactly which week because it depends on the cases, the number of people getting sick,” the report quoted Bancel as saying.

Bancel had told Financial Times last month that Moderna would not be ready to apply for emergency use of its Covid-19 vaccine before Nov. 25 at the earliest.

Bancel also highlighted that a ramping up of production is a challenge. “If one ingredient is missing, we cannot make the vaccine,” as per the Journal’s report.