BETHESDA, Md. (AP) — President Joe Biden says the U.S. will have enough supply of the COVID-19 vaccine by the end of the summer to inoculate 300 million Americans. Biden on Thursday toured the Viral Pathogenesis Laboratory at the sprawling National Institutes of Health complex just outside Washington that created the COVID-19 vaccine now manufactured by Moderna. Biden says the U.S. had secured contractual commitments from Moderna and Pfizer to deliver the 600 million doses of vaccine by the end of July — more than a month earlier than initially anticipated.