Russian authorities on Saturday began distributing the country's coronavirus vaccine Sputnik V for people in high-risk groups at 70 medical facilities across Moscow.

The advanced trial of the vaccine is still ongoing, but the shots had already been offered to people from high-risk groups, such as medical workers and teachers.

According to Moscow Mayor Sergei Sobyanin, those working in education and medical facilities, along with municipal workers, can get the shots.

President Vladimir Putin on Wednesday ordered the government to start “large-scale” vaccination in Russia by the end of next week, with medical workers and teachers the first in line.

Russia touted Sputnik V as the world’s “first registered COVID-19 vaccine” after the government gave it regulatory approval in early August.

The vaccine received the go-ahead after having been tested on only several dozen people, which drew considerable criticism at home and abroad.

Health experts say the vaccine needs to complete advanced studies among tens of thousands of people to ensure their safety and effectiveness.

Health Minister Mikhail Murashko said on Wednesday that more than 100,000 people in Russia have been given the shots.