LOS ANGELES - President Joe Biden said Tuesday during a COVID-19 briefing that he expects the U.S. to have enough vaccines available for all adults by the end of May, but amid the race to vaccinate as many Americans as possible, there have been reports across the country of thousands of doses of the coronavirus vaccine going to waste. RELATED: 4,400 doses of Moderna COVID-19 vaccine spoiled en route to Maine due to inadequate refrigerationHospital officials in Boston told the Associated Press on Jan.