President Joe Biden will announce later Tuesday that Merck & Co. /zigman2/quotes/209956077/composite MRK -1.60% will help make Johnson & Johnson's /zigman2/quotes/201724570/composite JNJ -0.85% one-shot COVID-19 vaccine in an unusual agreement between two competitors that could lead to a significant boost in supply, the Washington Post reported Tuesday, citing unnamed senior administration officials. The deal was brokered by the government as it works to expand manufacturing of the vaccine, which was granted emergency use authorization by the U.S. Food and Drug Administration on Saturday. Merck is one of the world's biggest vaccine makers and its own effort to develop an effective COVID vaccine failed. Merck will dedicate two facilities in the U.S. to the effort with one providing "fill-finish" services, putting vaccine in vials for distribution, while the other will make the vaccine itself, said the paper. That could double the supply compared with what J&J can achieve on its own, it said. The U.S. vaccine program has been hampered by a shortage of supply of vaccines. J&J shares were slightly higher premarket, but have gained 14% in the last 12 months, while the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.92% has gained 26%. Merck shares were up 0.4%, and have fallen 11% in the last 12 months.