BENGALURU: The Technical Advisory Committee (TAC) has accepted a proposal from a team of researchers from the Indian Institute of Science (IISc) to conduct a study to optimally streamline testing procedures, in preparation of a possible third wave, and fears over the new viral variant, Omicron.
The study, which is planned to be conducted with virologists and experts from the genome sequencing committee, will include genome sequencing on all those found to be positive through RT-PCR tests, while reporting a CT value of less than 25.
During an RT-PCR test analysis, lab researchers keep an eye on the DNA strand of the COVID-19-causing virus, SARS-CoV-2, which goes through several polymerase chain reaction (PCR) cycles till it replicates itself, which is referred to as cycle threshold (CT) value.
The Indian Council of Medical Research (ICMR) has set CT value of 35 as the limit. If it is below 35, it is 'positive', and above that is 'negative'. A CT value of 25 would indicate stronger viral presence.
The team of IISc researchers and accompanying experts have proposed to conduct genome sequencing tests for those reporting positive with a lower CT value to accurately pick out those with higher viral load for immediate treatment to mitigate COVID-19 spread.
The proposal, which was put out as a presentation at a recently held TAC meeting also aims at conducting neutralisation studies using the stored serum (sera) from the serosurveys on the lab-grown Omicron virus culture.
According to a presentation made by Prof Siva Athreya and Prof R Sundaresan of IISc, while there are several reasons why such a study is required, the scientists felt that currently the sampling strategy for testing may be leading to a bias in estimation of active infection.
They have stated that the sampling designs used may not be reflecting the true infected population. For instance, individuals with strong symptoms are more likely to be tested than those with no symptoms, resulting in biased estimates of prevalence (too high).
"There is a need to design and implement a sampling strategy to reduce the bias," the experts stated in the proposal. The study will also use data from earlier sentinel surveys sites used for the already conducted sero surveys and collect swabs from those people and do RT-PCR testing.
"It (the study) will provide valuable information to the state and enable it in identifying breakthrough infection rate and help assess level of vulnerability to Omicron in the population," the proposal stated.
The members of TAC, after discussing the proposal in detail, recommended that the Department of Health and Family Welfare should provide necessary support and data requested after necessary approvals.Sources said, the study by IISc and experts is expected to begin in the next few weeks.