Karnataka on Thursday confirmed 200 cases of Delta Covid-19 variant (B.1.617.2), taking the total number to 518 cases and 33 new cases of the Kappa variant (B.1.617.1), while cases of Delta Plus, the variant of concern, remained the same.
Members of the State genomic surveillance committee told DH that though the Delta variant was more infectious than the SARS-CoV-2, whether it caused more morbidity or mortality was yet to be investigated.
Prof Satyajit Mayor, Director, National Centre for Biological Sciences, and member of the State Genomic Surveillance Committee, told DH, "These cases may mostly be a backlog. What needs to be investigated is whether these cases have caused more harm in the state. It seems to be more infectious. Mortality data in this country is very sketchy. We don't have data on virulence and case fatality rate. Data from the UK says the Delta variant spreads faster. Covid cases seem to be on the decline and the Delta variant is replacing the variant of SARS-CoV-2, previously in circulation. If Delta variant reflects in the overall Covid surge, then it may be a cause of worry."
Dr Vishal Rao, Dean, Centre for Academic Research, HCG, another member of the State Genomic Surveillance Committee, told DH, "These cases seem to be at least three to four weeks old. Delta variant has been a predominant contributor to the second wave but it is showing up in numbers only now. This gives us a reaffirmation that it is a 'variant of concern'. The Kappa variant continues to be a variant of interest. But in the coming days, anything related to the sub-lineages of the B.1.617 are something we need to closely watch for."
Experts said there is a need to reduce the time lag in genomic sequencing. It takes about four weeks for completing the procedure on a batch, starting from sample collection, transportation of specimen and sequencing to the bio-informatic analysis.
Rao said if results are a month old, it is difficult to ascertain patient zero (index patient). "There is a need to trace back to patient zero and prospectively look at primary and secondary contacts. This is very essential to keep a track of the new variants. We're trying to create a heat map, if possible, district-wise, to get representation of cases.
"It's in discussion-stage but we need to move towards real-time monitoring rather than look at cases retrospectively. This data will now go to various districts and will be correlated with patient codes. Meta data analysis is yet to be done by the BBMP and other districts," Rao said.