BENGALURU: A team of doctors conducted a feasibility study to sequence a batch of patients who tested positive for Covid-19 through RT-PCR test and found that of the 44 genomic samples sequenced, 41 of them were of the new double mutant variant sub-lineage B.1.617.2, also known as the Delta variant.
The Delta variant is said to be at least 50 per cent more transmissible than the Alpha variant, which was first seen in the UK and has replaced all the other variants UK and South Africa in many states, including Karnataka.
The study found that it is feasible to sequence batch-level processing in a quick manner so that one can identify variants quickly and prepare for the next wave.
Dr U S Vishal Rao, Dean, Centre for Academic Research, HCG Cancer Center and member of expert committee, Covid-19 task force, and his team, including Dr Vamsi Veeramachaneni, Chief Scientific Officer at Strand Life Sciences, and Rohan Pais, COO, Strand, met Deputy Chief Minister Dr C N Ashwanth Narayan and submitted a report stressing that it is important to carry out genomic surveillance to identify emerging strains early so that scientists can establish the transmissibility of the new strains, assess vaccine protectiveness, verify RT-PCR kit performance and study clinical presentation.
“We know that this strain is going to continue evolving and more and more questions will be asked. Is it more transmissible? Is the vaccine protectiveness compromised or not? Are the RT-PCR kits that I am using in my local lab going to work against these new mutations or not? We need a quick way of analysing the data and trends,” explained Dr Vamsi to The New Sunday Express.
He said that the study showed that infections that result in ICU admissions are particularly important to monitor and genomic sequencing of all Covid ICU admissions may shed valuable insights.
Speaking to The New Sunday Express, Dr Vishal Rao said, “Clinical correlation of genetic lineages is very important. It is now evident that in many states, the second wave was caused by the Delta variant.”
He said such a spread could be prevented and policy decision on lockdown, tracing, tracking etc., can be effective if they are based on genomic data.
“There is a time gap in defining the genome and acting of policy on this finding. This clinical bridging has to be done. We found a great increase in black fungus cases, but not all were oxygen related. So, we will have to study if this variant has tendency of activating fungus etc,” he said.
Dr Vamsi is confident that aggressive fungus genomic mapping will help track the aggressive course of spread as well as vaccine efficiency. He explained that this pilot study showed that genome surveys can be effectively and quickly done.
“As clinicians, we are saying that ICUs must be monitored and our governments should be more proactive than reactive. We should keep track of the ICUs, especially where the number of deaths are high. It can be noted that even now, with the cases coming down, we have 80 per cent of the ICUs still occupied. We must do genome focus on them. Airports and ICUs are the places where genome data can be monitored for new variants,” Dr Vishal Rao said.
What is the Delta variant of Covid-19
There are many SARS-CoV-2 variants circulating globally. In India, we have so far found 8,572 variants from 28 states. One of these is the B.1.617 lineage, which was found in India in December, 2020. It is now found that it’s sub-lineage B.1.617.2 labelled as Delta by the WHO is a variant of concern.
Why so dangerous?
60-70%......more transmissible than contemporary lineages.
It has spread to more than 58 countries.
International reports claim increased risk of hospitalisation. Though the second wave in India showed similar trends, it is still not proved it is due to this variant.
Delta variant is present in all states but has infected most in Delhi, Andhra Pradesh, Gujarat, Maharashtra, Odisha and Telangana, which were the worst hit in the second surge.
Decreased efficacy in some vaccines.