Russia has become the first country in the world to register a coronavirus vaccine for use. Making a formal announcement of Tuesday, Russian President Vladimir Putin said that the vaccine has proven efficient during tests, offering "sustainable immunity" against the coronavirus. "This morning, for the first time in the world, a vaccine against the new coronavirus was registered" in Russia, he said during a televised video conference call with government ministers. Putin claimed that the vaccine underwent the necessary tests. He added that one of his two daughters has received a shot of the vaccine and is feeling well. The move comes despite many scientists in Russia and abroad questioning the decision to make the vaccine available for use before Phase 3 trials, which normally last for months and involve thousands of people. Putin said that his daughter had a temperature of 38 degrees Celsius on the day of the first vaccine injection, and then it dropped to just over 37C on the following day. After the second shot she again had a slight increase in temperature. "She's feeling well and has a high number of antibodies," Putin added. He didn't specify which of his two daughters received the vaccine. The Health Ministry said in a statement on Tuesday that the vaccine is expected to provide immunity from the coronavirus for up to two years. Russian authorities have said that medical workers, teachers and other risk groups will be the first to be inoculated. Russia said 20 countries have pre-ordered a billion doses of vaccine named ‘Sputnik V' for foreign markets, a reference to the world's first satellite. Deputy Prime Minister Tatyana Golikova said that the vaccination of doctors could start as early as this month. Large-scale production of the vaccine will start in September, and mass vaccination may begin as early as October, officials said. — Agencies