With 20 more people testing positive for the new UK variant of Sars-CoV-2, the virus that causes coronavirus disease (Covid-19), the total number of UK returnees having tested positive for the mutant virus in the country has reached 58.

The results are based on the genome sequencing of positive samples released by the Indian Sars-CoV-2 Genomics Consortium (Insacog) labs that the Centre has specifically created for the purpose of monitoring any kind of mutations in the virus.

The samples have so far been sequenced in six of the 10 designated labs across the country.

Among the sequenced samples, 10 samples tested positive in NIMHANS, Bengaluru, three in CCMB, Hyderabad, five in NIV, Pune, 11 in IGIB, Delhi, eight in NCDC, New Delhi, and one in NCBG, Kolkata.

NCBS, InSTEM, Bengaluru, CDFD Hyderabad, ILS Bhubaneswar, and NCCS Pune have so far found no traces of the UK variant among the samples that have been sequenced in their labs.

From November 25 to December 23, 2020, about 33,000 passengers disembarked at various Indian airports from UK.

All these passengers are being tracked and subjected by states to reverse transcription-polymerase chain reaction (RT-PCR) tests to detect Covid-19.

“All these persons have been kept in single-room isolation in designated health care facilities by respective state governments. Their close contacts have also been put under quarantine. Comprehensive contact tracing has been initiated for co-travellers, family contacts and others. Genome sequencing on other specimens is going on,” said the Union health ministry in a statement.

“The situation is under careful watch and regular advice is being provided to the states for enhanced surveillance, containment, testing and dispatch of samples to Insacog labs,” the statement further read.

The Indian government had suspended air travel from the United Kingdom December 23 onwards after a new variant of Sars-CoV-2 was found to be circulating in London and other parts of the country.

The new variant – which has 23 mutations, including one on the receptor binding protein on the spike used by the virus to enter the human cells – is thought to be 70% more transmissible, raising concerns of super-spreading events.

However, doctors monitoring these patients have not found severe illness because of the new variant.

The presence of the new UK variant has already been reported by Denmark, Netherlands, Australia, Italy, Sweden, France, Spain, Switzerland, Germany, Canada, Japan, Lebanon and Singapore, so far.