Johnson & Johnson's COVID-19 vaccine is on track to become the third coronavirus vaccine available to US citizens.

Moderna and Pfizer's vaccines are currently the only two COVID-19 vaccinations authorized for use by the Food and Drug Administration (FDA), but according to a Friday (Jan. 29) report from Johnson & Johnson, that may soon change. 

According to ABC News, the company announced Friday that its one-dose vaccine is 66% effective at preventing symptomatic disease and 85% effective against preventing severe illness. 

Johnson & Johnson explained that the vaccine's level of protection varies by region, with the vaccine demonstrating 66% effectiveness overall, 72% in the United States, 66% in Latin America and 57% in South Africa after four weeks.

According to the company, the vaccine was 85% effective in preventing severe disease four weeks after vaccination in all adults. Johnson & Johnson also says its vaccine offered complete protection against COVID-related hospitalizations four weeks after vaccination.

“We’re proud to have reached this critical milestone and our commitment to address this global health crisis continues with urgency for everyone, everywhere,” CEO Alex Gorsky said in a statement.

The vaccine test results were based on 468 confirmed COVID-19 infections among the phase three trial’s more than 43,000 volunteers, Johnson & Johnson says. The company added that the trial includes those infected with B.1.351, which is a new, highly contagious strain found in South Africa.

Johnson and Johnson's vaccine differs from Pfizer’s and Moderna’s, which require two doses given about three to four weeks apart. Johnson & Johnson’s requires only one dose, and the company says it can be shipped at between 2 to 8 degrees Celsius/ 36 to 46 degrees Fahrenheit.

This is yet another difference as Pfizer’s vaccine needs to be stored in ultra cold freezers that keep it between negative 80 and negative 60 degrees Celsius, or between negative 112 and negative 76 degrees Fahrenheit. Moderna’s vaccines, likewise, must be shipped at between negative 25 and negative 15 degrees Celsius, or negative 13 and 5 degrees Fahrenheit.

The company is now planning studies in children and pregnant women to ensure the vaccine is also safe and effective for those groups.

If authorized, the Johnson & Johnson vaccine would help ease a strained vaccine supply.

The company said it's capable of delivering 100 million doses to the U.S. by June, if the FDA grants approval to do so.