KARACHI: Two more cases of the UK Covid-19 variant were detected on Thursday, raising the total number of patients carrying the potentially more contagious form of coronavirus to five in Sindh, health department sources told Dawn, citing preliminary laboratory results.

“Both men in their 20s are UK returnees and residents of Karachi. They are stable with no symptoms of the disease and under home isolation,” an official of the health department said.

So far, five UK returnees, including three women, had been detected with the new Covid-19 variant out of the 12 testing positive for coronavirus, he added.

Further tests of the patients carrying the UK Covid-19 variant are being done at the Aga Khan University Hospital while their houses are placed under police surveillance.

It may be recalled that the first case of the new variant of coronavirus (B.1.1.7) can be traced back to late September in the south of England. Since then, it has spread to over 50 countries.

According to experts, a certain strain of virus is considered a variant when it has enough mutations to change a minor portion of its genetic code. The most recent variant found in the UK, known as B.1.1.7, meets that benchmark.

All currently known variants of Covid-19, they say, belong to the Sars-CoV-2 strain and have not mutated enough to be classified as their own strain.

Some UK researchers believe that this variant is up to 70 per cent more transmissible because it has 22 coding changes to the virus genome.

However, there is no evidence to suggest that the variant is any deadlier than previously known strains of the coronavirus, or that it makes people any sicker or is resistant to the vaccines that have been developed.

Published in Dawn, January 1st, 2021