The number of confirmed coronavirus cases worldwide has topped 20 million, more than half from the United States, India and Brazil, while Russia has become the first country to approve a COVID-19 vaccine.
Russian President Vladimir Putin said one of his two adult daughters had already been inoculated with the cleared vaccine, which he described as effective.
"She's feeling well and has a high number of antibodies," Putin said.
Russia has reported more than 890,000 cases, the fourth-highest total in the world, according to a Johns Hopkins University tally that also showed total confirmed cases globally surpassing 20 million on Tuesday.
It took roughly six months to get to 10 million cases after the virus first appeared in central China. It took just over six weeks to double.
An analysis of data through August 9 showed the US, India and Brazil accounted for nearly two-thirds of all reported infections since the world hit 15 million coronavirus cases on July 22.
Health officials believe the actual number of infected is much higher, given testing limitations and that as many as 40 per cent of those with the virus show no symptoms.
As a result, the race to develop and deliver a vaccine has topped the global health care and geopolitical agenda, even as the United Nations warns any vaccine must be safe and made available to all, not just the wealthy.
Putin said the Russian vaccine underwent necessary tests and offered lasting immunity.
But scientists have warned that rushing to start using the vaccine before Phase 3 trials - which normally last for months - could backfire.
"The point is not to be first with a vaccine," US Health and Human Services Secretary Alex Azar said on Tuesday.
"The point is to have a vaccine that is safe and effective for the American people and the people of the world."
The US has a half-dozen vaccine candidates under development, China has begun inoculations with an experimental vaccine and European countries have several trials underway.
In Europe, countries that appeared to have gotten their outbreaks under control during nationwide lockdowns and lifted many public restrictions worked to prevent a resurgence of the virus.
Finland joined France and Germany in announcing it would test travellers from at-risk countries upon arrival.
Spain, which along with Italy was hardest hit when the virus first exploded, now has the most confirmed cases in western Europe at nearly 323,000.
The number of new cases has risen steadily in Spain since its strict, three-month lockdown ended on June 21, reaching 1486 on Monday.
In Greece, which imposed strict lockdown measures early and kept its reported cases low during the height of the European epidemic, the government on Monday ordered bars, restaurants and cafes in several regions to shut between midnight and 7 am.
The number of new cases reported daily continues to rise in India, hitting a rolling seven-day average of 58,768.
In the US, which so far has more than 5 million confirmed cases, the daily average remains over 53,000.
In the 45 days it took reported coronavirus cases worldwide to double to 20 million, the number of reported virus deaths climbed to 736,191 from 499,506, an average of more than 5200 a day.
About one-fifth of reported deaths, or more than 163,000, have been in the US.
Australian Associated Press