The Gaithersburg, Md., company also said it now intended to file for clearance of the vaccine with the U.S. Food and Drug Administration, as well as with U.K. and European regulators, in the third quarter.
And it said it would hit its production target of 150 million shots a month in the fourth quarter.
Reuters reported that Novavax had earlier said the vaccine could be authorized in the U.S. as early as May. And its previous goal for the output target was the third quarter, the news service said.
Delays in clinical-trial results coupled with manufacturing delays had slowed the process by which the company would seek FDA clearance, people briefed on the matter had told the Washington Post.
At last check Novavax shares were trading 12% lower at $140.50. They'd closed the regular Monday trading session down 8.8% at $160.50.
Novavax reported a first-quarter net loss of $223 million, or $3.05 a share, compared with a loss of $26 million, or 58 cents a share, in the year-earlier quarter.
The latest result was stronger than the FactSet consensus estimate of a GAAP loss of $3.60 a share.
Revenue jumped to $447 million from $3 million in the year-earlier period and exceeded the FactSet call of $233.9 million.
The revenue increase reflected the vaccine-development services Novavax provided under the U.S. government and Coalition for Epidemic Preparedness Innovations agreements, the company said.
"Novavax made great strides over the first quarter to pave the path for our COVID-19 vaccine candidate, NVX-CoV2373, notably achieving statistically significant efficacy across our Phase 3 U.K. and Phase 2b South Africa trials," President and Chief Executive Stanley C. Erck said in a statement.
The company said it had secured additional manufacturing and supply agreements, expanding its global supply chain to more than 10 countries.
"In the coming months, we look forward to delivering on critical milestones, including announcing final data from our Prevent-19 Phase 3 trial, completing our regulatory submissions, evaluating" the COVID-19 vaccine candidate "in younger populations and continuing to develop our booster strategy to address the evolving COVID-19 pandemic," added Erck.
Rolling reviews have been initiated with regulatory authorities in Canada, Australia and New Zealand, the company said.
At March 31, Novavax's cash, cash equivalents, marketable securities and restricted cash nearly tripled to $2 billion from $806 million at Dec. 31.