French drugmaker Sanofi SA said on Tuesday it expects to get approval for the potential COVID-19 vaccine it is developing with Britain's GlaxoSmithKline Plc by the first half of next year, faster than previously anticipated.

Sanofi, which is hosting a virtual research and development event, and GSK had said in April the vaccine, if successful, would be available in the second half of 2021.

"We are being guided by our dialogue with regulatory authorities," Sanofi research chief John Reed told reporters, when asked about the accelerated time frame.

There are currently no vaccines to prevent the coronavirus that has infected more than 9 million people and killed over 469,000 globally, and only a couple of medicines that have demonstrated benefit in hospitalized COVID-19 patients in clinical trials.

Many drugmakers have embarked in a race to come up with a safe and effective vaccine that can be produced at large scale.

Moderna Inc, the University of Oxford in collaboration with AstraZeneca Plc, and an alliance of BioNTech and Pfizer Inc grabbed headlines by moving to human trials as early as March.

Sanofi Chief Executive Paul Hudson said the firsts in the race now were not assured of securing victory.

"There are companies moving faster, but let us be brutally clear, speed has three downsides," he said of competition.

"They are using existing work, in many cases done for SARS; it is likely not to be as efficacious; and there is no guarantee on supply in large volumes," Hudson said.

The probability of success for Sanofi is "higher than anybody else," the CEO said.

The comments echoed those of GSK, whose chief medical officer for vaccines told Reuters on Friday the company was aiming at quality before speed.