The U.S. Food and Drug Administration has authorized use of a second COVID-19 vaccine for people age of 18 and over, a move that will trigger the shipment of millions more doses to hospitals and nursing homes within days.

Like its competitor Pfizer, the Moderna vaccine was believed to be both safe and highly effective. After tracking some 30,000 volunteers, Moderna estimated it as 94% effective in preventing COVID-19 illness with few serious side effects.

"With the availability of two vaccines now for the prevention of COVID-19, the FDA has taken another crucial step in the fight against this global pandemic that is causing vast numbers of hospitalizations and deaths in the United States each day," said FDA Commissioner Dr. Stephen M. Hahn.

The vaccine was developed with assistance from the National Institute of Allergy and Infectious Diseases, led by Dr. Anthony Fauci. He has said there is no real difference between the Moderna and Pfizer vaccines, which rely on similar technology.

"It is my hope that all Americans will protect themselves by getting vaccinated when the vaccine becomes available to them. That is how our country will begin to heal and move forward," he said in a statement.