New York: Vaccine maker Novavax Inc said on Monday it has pushed back the start of a U.S.-based, late-stage trial for its experimental COVID-19 vaccine and now expects it to begin in the coming weeks instead of November.It is the second time that Novavax, which already has a late-stage UK trial underway, has rescheduled the Phase 3 trial after first flagging an October start, hampered by issues in scaling up its manufacturing.Shares of the U.S.-based company, which lags behind larger rivals Pfizer Inc and Moderna Inc in their COVID-19 vaccine development timelines, fell 6% on the latest delay.Novavax plans to use vaccine material produced at commercial scale for the trial in the United States and Mexico and has been working closely with the.