(Reuters) -Novavax Inc on Monday again delayed its timeline for ramping up COVID-19 vaccine production and said it now does not expect to seek regulatory authorization for the shot in the United States, Britain and Europe until the third quarter of 2021, sending its shares tumbling. The Maryland-based company has repeatedly pushed back production forecasts and has struggled to access raw materials and equipment needed to make its vaccine. Novavax shares fell more than 9% in extended trading after closing nearly 9% lower on Monday. Novavax said it does not expect to hit its production target of 150 million shots per month until the fourth quarter of 2021, later than its previous forecast of sometime in the third quarter. It had also previously said it could see U.S. regulatory authorization as soon as May. But on a call to discuss first-quarter results, Chief Executive Stanley Erck said major manufacturing hurdles have been cleared and that all of its facilities can now produce COVID-19 vaccine at commercial scale. “We know that we’re delayed from where we thought we’d be at this point,” Erck said. “Now we’re giving guidance that nearly all of the major challenges have been overcome and we can clearly see the light at the end of the tunnel.” He said Novavax currently has about 30 million to 40 million doses on the shelves and its factories are making more each week. While vaccine demand is declining in the United States, the Novavax shot is expected to play an important role in global inoculation efforts. Many countries such as India and much of South America still have low vaccination rates and are desperate for supplies. “Unmet demand outside of the United States has resulted in continued demand for Novavax’s vaccine,” said Chief Commercial Officer John Trizzino. The company has promised to supply 200 million shots to countries around the globe, in addition to the 1.1 billion doses it has committed to the COVAX international vaccine sharing program, Trizzino said. Novavax"s shot has yet to be authorized in any country, but the company reported late-stage data from a UK trial that showed it to be highly effective against the original version of the coronavirus and a newer, more contagious variant first found in Britain. (refini.tv/3bfL38D) Data from its pivotal U.S. and Mexico trial is expected to be released in the current quarter. Novavax reported a net loss for the first quarter of $223 million. It had $447 million in revenue, mostly payments from the U.S. government for its COVID-19 vaccine research, and spent $593 million on research and development. Reporting by Trisha Roy in Bengaluru and Carl O’Donnell in New York; Editing by Bill Berkrot Our Standards: The Thomson Reuters Trust Principles.