"Have a look at influenza. We change the vaccine composition twice a year - for the northern and southern hemisphere - and we're able to issue vaccines very, very quickly to combat the predominant flu strains," Ryan said during a social media question and answer session.

"There's no reason, even down the line, if this virus evolves to a point where our vaccines begin to lose effectiveness, (why we should not be able to vaccinate against COVID-19). We can adapt those vaccines, and I believe we can adapt those vaccines quickly."

The University of Oxford expects efficacy data from a study of its COVID-19 vaccine against the UK variant of the coronavirus by next week, a lead scientist said on Wednesday at a virtual meeting of a US CDC advisory panel.

"Since the middle of December, that (UK) variant has been dominant and spread so rapidly. And so, we should be able to put together an analysis on efficacy against that probably by next week," said Andrew Pollard, director of the Oxford Vaccine Group.

Oxford University has developed the vaccine for the variant along with UK drug maker AstraZeneca.

They will also work on a vaccine version that will target the South African variant of the virus, according to a media report on Tuesday.

British scientists have said the UK variant that is behind a surge in COVID-19 infections in the country may be not only more transmissible but also more lethal - with a mortality risk about 30 per cent higher than other variants.

The Oxford-AstraZeneca duo, once frontrunners, have been left behind in the vaccine race by Pfizer Inc and Moderna Inc, which have both found their vaccines to be effective against the UK variant.

The UK Office for National Statistics (ONS) said on Wednesday people infected with the new UK variant are less likely to report a loss of taste and smell.

The ONS said they were more likely to report "classic" symptoms of the virus such as a cough and a fever.

Australian Associated Press