Four foreign-return in Cachar test negative for COVID; Omicron test “inconclusive”

On December 6, 2021, the Cachar District Health Department informed that four individuals who have returned from foreign countries have tested positive for COVID 19 after reaching Silchar. Three of them had returned from Saudi Arabia while one was from Finland. 

This came in as a cause of concern as Omicron, a new variant of Coronavirus started spreading fast in the other parts of the country. If the variant is Omicron or not is something that a routine RT-PCR test cannot determine. For the identification of the gene, genome sequencing of samples is essential.

Accordingly, samples of all four were sent to the National Institute of Biomedical Genomics, Kalyani, West Bengal for genome sequencing. The district health department informed that all four of them were kept in isolation and the process to trace those who came in their contact had begun.

Medical sources confirmed that all four of them have tested negative for COVID 19 and their condition is stable. The question that thousands in Cachar were waiting for, Omicron or not, is something that remains unanswered.

National Institute of Biomedical Genomics, Kalyani, West Bengal concluded the genome sequencing as “inconclusive”. Meaning, the genomic sequencing could not identify the genes properly to conclude if it is the Omicron variant or not. A professor in Microbiology explained the reason why it was concluded as inconclusive.

• The professor explained, “What we need to understand is the CT-Value. It is always advised that the samples sent for genomic sequencing must have a high viral load. This means the CT- Value should be 25 or lower. The lower the value the higher the viral load. At 35, it is considered to be COVID negative in India, in some countries it is 30. The samples collected from the four individuals had a CT-Value above 30 and so, the genomic sequencing could not confirm if the ‘S’ gene had dropped out. Therefore, it concluded as inconclusive, and so, Omicron and not cannot be confirmed.”

Sources in Silchar Medical College and Hospital also informed that the samples of SMCH-doctors who had tested positive have been sent for Genomic Sequencing. Those samples have a high viral load as most of them reported a CT-Value of less than 25. Their reports are awaited and SMCH is expecting to get a response only next year.