The Food and Drug Administration moved Friday to grant an emergency use authorization to drugmaker Modernas coronavirus vaccine, the second one approved for use in the U.S.

The agencys decision came after a daylong meeting of a panel of experts on Thursday to discuss the vaccines safety, efficacy and side effects. Twenty panelists voted to formally recommend that the FDA approve the drug for use in Americans age 18 and older, while one abstained.

Through the FDAs open and transparent scientific review process, two COVID-19 vaccines have been authorized in an expedited timeframe while adhering to the rigorous standards for safety, effectiveness, and manufacturing quality needed to support emergency use authorization that the American people have come to expect from the FDA, the agencys commissioner, Stephen Hahn, said in a statement.

These standards and our review process, which are the same we have used in reviewing the first COVID-19 vaccine and intend to use for any other COVID-19 vaccines, included input from independent scientific and public health experts as well as a thorough analysis of the data by the agencys career staff, Hahn said.

As with the Pfizer-BioNTech vaccine, a committee within the Centers for Disease Control and Prevention will now issue a recommendation on who should be first to get the shots.

Moderna, a Massachusetts-based company, expects to produce around 20 million doses by the end of this year.

It was among the first companies to secure pledged funding from the U.S. government to help cover research and development of its vaccine. In return, the federal government is expected to receive 200 million doses, which it will distribute across the country, with the option to acquire an additional 300 million doses.

The Moderna vaccine is administered in two doses and has been found to be nearly 95% effective.

Its design is similar to the vaccine made by Pfizer, which secured approval late last week and started being administered to American patients on Monday.

Both drugs use mRNA, or messenger RNA, to teach the human body how to recognize the coronaviruss telltale spike protein, which is often shown in illustrations of the virus, in order to trigger a strong immune response when the virus is encountered for real. Neither drug involves injecting the coronavirus into the body just instructions for a small part, which are then quickly broken down.

There is one key difference between them: The Moderna vials do not need to be stored at the same super-low temperature as the Pfizer vials. Modernas drug can be kept in regular freezers, making it easier to distribute to facilities that may not have specialized equipment.

Pfizers drug is also recommended for a slightly wider range of use: The FDA cleared it for people aged 16 and up.

Evidence from Modernas clinical trials suggests that its vaccine protects people not only from getting sick with COVID-19 but also from the worst effects of the virus. Some of the most common side effects include pain at the site of injection, fatigue, headache and body aches, which dissipate after a day or two.

Never before in medical history have scientists been able to design, test and produce a vaccine for a novel disease in such a short time under one year for both Moderna and Pfizer. Many other vaccines are still in the pipeline.

The drugs emergency approval has come at a crucial time: The country has already passed 300,000 confirmed COVID-19 deaths and is now logging well over 3,000 deaths per day as the Christmas and New Years holidays approach. Those troubling trends can be expected to continue if Americans gather with friends and family in spite of public health guidelines urging people to stay home with those in their household.