Global coronavirus cases are expected to pass 30 million on Thursday, according to a Reuters tally, with the pandemic showing no signs of slowing.
Health experts stress that official data almost certainly under-reports both infections and deaths, particularly in countries with limited testing capacity.
The race to develop and bring to market a novel coronavirus vaccine has grown increasingly frenetic in recent weeks with about 200 candidates in development globally.
US President Donald Trump has said his country could have a vaccine ready for distribution before the US election on November 3, while a Chinese health official this week said China may have a vaccine ready for public use as early as November.
While the trajectory of the coronavirus still falls far short of the 1918 Spanish flu, which infected an estimated 500 million people, killing at least 10 percent of them, experts worry the available data is underplaying the true impact of the pandemic.