Kerala

‘Genome sequencing could help identify reason behind rise in COVID-19 cases in Kerala’

While Kerala has seen a recent rise in COVID-19 cases even as other States appear to have dodged a second surge so far, experts say that genome sequencing could help figure out the reasons for the growing figures.

Kerala has contributed to 43% of the new cases reported in India in the past one week, said Dr. Rijo John, health economist, who has been analysing the numbers. Testing stands at a seven-day average of around 55,000 per day, which is lower than the average figure of around 60,000 to 62,000 during the peak the State witnessed in October, he said.

“We already saw a peak in October of around 8,000 to 9,000 new cases daily. It appears as if we are approaching a new peak now, but testing has stagnated with no justification,” he said.

“The onset was delayed. Once transmission starts expanding, susceptible pools wherever they are, are at risk of getting the infection eventually,” said Dr. Giridhar R. Babu, Professor of Epidemiology at the Public Health Foundation of India.

“You could have had a fewer number of cases if testing was disproportionately distributed. In some States, more than 50% of the tests were concentrated in the State capitals and the rest distributed across the State. Kerala has wide distribution of tests across the State, so if there is an infection, you might pick it up anywhere,” he said.

“Most importantly, when the susceptible pool is readily available for infection, which variant of the virus has caused this sudden surge in cases is important to examine. Earlier, the outbreaks in the country were mostly associated with the initial variants spreading. Is it a possibility that the new peaks are because of the new variations?” asked Dr. Babu, adding that results of genomic sequencing associated with Kerala’s outbreaks would be crucial.

Growing caseloads

Ernakulam, Alappuzha and Pathanamthitta have seen rapidly growing caseloads in the past few weeks. The genome sequencing study that the State is undertaking might help identify reasons for a rise in cases in some pockets and determine if that can be attributed to variations in the strains of the virus, said an infectious diseases expert in the government sector who asked not to be identified. “The urban-rural divide does not really apply to Kerala since there is mobility across areas,” he said.

One hundred samples are being collected from each district every month for three months for genome sequencing, he said. Reverse quarantine measures in the State might have failed to some extent since the death audits point to a large number of deaths among people with comorbidities, he added.

‘Strange situation’

With the current slow pace of vaccination, it could take several years to attain some sort of vaccine-induced herd immunity, which makes it crucial to not drop our guard, Dr. John said.

“Kerala is the only State where the cases plateaued and began to rise again, which is a strange situation. Some States, where there is large-scale COVID-unfriendly behaviour but few cases, remain a mystery. It cannot be that every other State is under-reporting figures,” he said.

The infectious diseases expert agreed that the dip in the other States when compared to the increase in Kerala, was perplexing.

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Printable version | Mar 7, 2021 8:57:55 AM | https://www.thehindu.com/news/national/kerala/genome-sequencing-could-help-identify-reason-for-rise-in-cases/article33662917.ece

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