There are around 4,000 variants of the virus that causes COVID-19 around the world now so all vaccine manufacturers including Pfizer Inc and AstraZeneca Plc are trying to improve their vaccines, a British minister said.

Thousands of variants of the type of coronavirus that causes COVID-19 have been documented as the virus mutates, including the so-called British, South African and Brazilian variants which appear to spread more swiftly than others.

There are around 4,000 variants of the virus that causes COVID-19 around the world now so all vaccine manufacturers including Pfizer Inc and AstraZeneca Plc are trying to improve their vaccines, a British minister said.

Thousands of variants of the type of coronavirus that causes COVID-19 have been documented as the virus mutates, including the so-called British, South African and Brazilian variants which appear to spread more swiftly than others.

"All manufacturers, Pfizer-BioNTech, Moderna, Oxford-AstraZeneca and others are looking at how they can improve their vaccine to make sure that we are ready for any variant - there are about 4,000 variants around the world of COVID now."

While thousands of variants have arisen as the virus mutates on replication, only a very small minority are likely to be important and to change the virus in an appreciable way, according to the British Medical Journal.

"We have the largest genome sequencing industry - we have about 50% of the world's genome sequencing industry - and we are keeping a library of all the variants so that we are ready to respond - whether in the autumn or beyond - to any challenge that the virus may present and produce the next vaccine," Zahawi said.

The novel coronavirus - known by scientists as SARS-CoV-2 - has killed 2.268 million people worldwide since it emerged in China in late 2019, according to Johns Hopkins University of Medicine.

(With inputs from agencies)