The United States (US) has authorized the use of J&J's single-dose Covid-19 vaccine

 The United States (US) government gave permission to use the single-dose Covid-19 vaccine produced by Johnson & Johnson (J&J) on Saturday (27/2). This licensing of the J&J vaccine will allow millions more Americans to be vaccinated in the coming weeks and prepare them for additional approval worldwide.

The US Food and Drug Administration (FDA) announced the authorization of the emergency use of J&J's single-dose vaccine for adults 18 years and older following Friday's unanimous approval by an outside panel of experts. J&J vaccine deliveries are expected to start on Sunday or Monday.

US President Joe Biden praised the move, but warned Americans not to celebrate too soon. "Things are still likely to get even worse as new variants spread," he said in a statement. He urged people to continue to wash their hands, wear masks and maintain social distancing.

"There is a light at the end of the tunnel, but we cannot be caught off guard now or assume that victory is inevitable," Biden said.

In a global trial of the J&J vaccine involving 44,000 people, the vaccine was 66% effective at preventing moderate to severe Covid-19 four weeks after inoculation, and 100% effective in preventing hospitalizations and deaths from the virus.

There were very few serious side effects reported in the trial, which also offers some preliminary evidence that the J&J vaccine reduces asymptomatic infections.

The J&J vaccine is expected to be widely used worldwide because it can be shipped and stored at normal refrigerator temperatures, making distribution easier than the Pfizer Inc / BioNTech SE and Moderna Inc vaccines, which are shipped frozen.

"This has the potential to play a very important role if we have sufficient doses because this is only a single dose vaccine and that will make it attractive to hard-to-reach people," said Dr. William Schaffner, infectious disease specialist at Vanderbilt University.

Schaffner said the fact that the J&J vaccine could be stored at normal cooling temperatures would make it easier to distribute.

The US government, which has purchased 100 million doses of J&J vaccine, plans to distribute about 3 million to 4 million doses this week. That would be on top of the roughly 16 million doses of Pfizer / BioNTech and Moderna vaccines that are already planned to be shipped across the country.

"We are ready to launch," White House Senior Advisor Andy Slavitt wrote on Twitter following the authorization of the J&J vaccine.

J&J plans to deliver a total of 20 million doses by the end of March 2020, which together with a total of more than 220 million doses expected from Pfizer and Moderna will be sufficient to fully vaccinate 130 million people in the United States.

So far, the United States has distributed more than 90 million doses of the Covid-19 vaccine, some of which have been used for second shots. About 14% of Americans have received at least one dose, according to US government data.