The first confirmed case of Omicron sub-variant BA.4 has prompted the National Centre for Disease Control (NCDC) to resume contact tracing after a gap of almost three months.An NCDC team has already tested 24-25 people who came in direct contact with the African national infected with the BA.4 sub variant, the first case in India detected in Hyderabad, said a government official on condition of anonymity.The Union health ministry and Indian SARS-CoV-2 Consortium on Genomics (INSACOG) called a meeting on Friday to firm up a surveillance strategy. Last week, the European Centre for Disease Prevention and Control (ECDC) had asked countries to be vigilant about the BA.4 and BA.5 variants after a spike in BA.5 infections in Portugal.“In February, the government stopped contact tracing. However, after a meeting by INSACOG and the Union health ministry, extensive contact tracing has been initiated for those who came in contact with the person. The report is likely to come by next week” the official said.On Thursday, Mint reported the African national landed in India for a business meeting but was found covid positive on his arrival at Hyderabad airport. His sample was sent for sequencing and was found to be BA.4. Queries to a health ministry spokespeople early on Friday did not elicit a response till press time.According to the World Health Organization, contact tracing is key to stop further transmission of SARS-CoV-2. Though ECDC said BA.4 and BA.5 are variants of concern, experts said that as of now it is difficult to predict public health concerns. “INASCOG is a platform for variant mapping. More variants will emerge, but only time will tell if a new variant is a public health concern. So, one should neither create panic nor lower vigil,” said Dr Samiran Panda, additional director general at the Indian Council of Medical Research.In the past 24 hours, 2,259 fresh covid cases were reported in India to take the tally of active cases to 15,044 with a weekly positivity rate at 0.53%. Delhi (2,377), Haryana (1,248), Uttar Pradesh (898), Kerala (3,579), Karnataka (1,726) and Maharashtra (1,720) have the maximum active cases. Approximately 2,614 patients have recovered from covid in the last 24 hours.Union health secretary Rajesh Bhushan has also asked states and Union Territories to accelerate vaccination, in view of a steady fall in vaccination numbers in some states.