BENGALURU: While the state war room’s daily bulletin on Covid-19 figures presents a reassuring picture, two sub-lineages of the SARSCoV- 2 Delta variant — the AY4 and AY12 — have been detected in samples from Bengaluru, raising concerns among experts about a changing virus and the possibility of it developing the capability to evade antibodies generated through vaccination.
Strand Life Sciences, which did the sequencing here, was given a mandate by the Covid Task Force in Karnataka to start genome sequencing to help detect trends in mutations in the state. The sequencing revealed 30 per cent mutation in the Delta AY4 variant while it was just 3 per cent in AY12. But a senior doctor, privy to the genome sequencing, explained to The New Indian Express, “However little the mutation, we cannot be complacent as no studies have been conducted as to what effects these can have.
A layman would think this is very less mutation than the Delta variant, so it is safe. But virologists globally say that’s not true, as it is changing its form. The mutation, even if little, may help the virus acquire some other mutation elsewhere. We still don’t know, but it is definitely changing and it needs closer examination.” The analysis said the virus was changing and Delta’s sub-lineages are spread across Bengaluru Urban and are also picking up new mutations.
According to a recent bulletin of Indian SARS-CoV-2 Genomics Consortium (INSACOG), the AY12 sub-lineage was the one driving the Covid-19 surge in Israel, despite 60 per cent of that country’s population covered by vaccination.
Many mutations yet to be reported on global databases
The new lineages are being monitored closely by the consortium. What is of concern is that many of the mutations are novel and not yet reported in global databases. The mutations that were found in the AY4 and AY12 Delta variants were N439K (present in 7 sequences), N440Y/ T/F (present in 8 sequences), L441Y/S/G/A/C/D/V/I (in 7 sequences), D442I/V/Y/F (in 9 sequences), S443E/V/Y/W/F (in 7 sequences), and K444F/N/V/T/S/ V(in 7 sequences).
According to earlier studies, variants with N439K mutation facilitate the fitness of the virus and enables it to evade antibody mediated immunity — which means these can change the behaviour of the virus. The report submitted to the State Government has sought monitoring of cases closely to see if there is any increase in the frequency of these mutations, especially because the effect of many other mutations on the virus has not been observed and “the presence of these mutations might signal for a new variant.