RT-PCR can predict Covid severity: IISc study

Nasal swab samples collected for RT-PCR testing are not just useful to diagnose if a patient is Covid-positive or negative but can also help in predicting the severity of the disease, according to researchers at the Indian Institute of Science (IISc), Bengaluru.

The findings were made by scientists following detailed big-data analysis and validation in nasal swab samples received at the institute’s Covid-19 Diagnostic Facility, which has processed over one lakh samples since it was started in May 2020.

Dr Shashank Tripathi of the Centre for Infectious Disease Research (CIDR) at IISc explained that the premise for the research began last year after scientists began to wonder what other pertinent information could be generated out of swab samples being sent to the diagnostic centre.

“Through meta-analysis we found that four host genes acted as prognostic markers of severe Covid-19. That is, their gene signature reveals the severity of infection in a patient, with a sensitivity of up to 93%,” said Dr Tripathi, corresponding author for the study, which was published in The Lancet’s EBioMedicine open-access medical journal.

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The four genes are members of the S100 family of genes, which have a broad range of intracellular and extracellular functions in the body. “By determining severity at the time of testing, the triaging system could decide well beforehand if a positive case is likely to be hospitalised,” Dr Tripathi said.

The researchers used 63 samples to validate their study. Thirty-one were from Covid-positive individuals and 32 from Covid-negative cases. Among the 31 positive samples, 16 were from seriously symptomatic individuals and 15 from mild or asymptomatic individuals.

Dr Tripathi added that the testing for the prognostic signature can be performed using standard RT-PCR methods and equipment, which is already being employed by Covid-19 diagnostic labs across India.

Currently, CT-scans, blood tests and X-rays are used to determine disease severity in an infected person.

New drug

Guided by their big-data analysis, IISc researchers said they also sought to check for potential new drugs to treat Covid-19. They found that an FDA-approved drug, Auranofin, which is used to treat patients with severe rheumatoid arthritis, showed promise.

This was subsequently verified when the drug was able to mitigate novel coronavirus replication in vitro and in animal studies.

“Human trials will be required for further evaluation,” Dr Tripathi said.