In order to ensure preparedness, the State’s COVID-19 Technical Advisory Committee (TAC) has sought help from experts at IISc and Indian Statistical Institute (ISI) to estimate using mathematical modelling, the burden of COVID-19 in Bengaluru and the entire State based on the emerging trajectory of BF.7.
At its 189th meeting held on December 25, Sunday, the TAC requested IISc professor Rajesh Sundaresan and ISI professor Siva Athreya to prepare an estimate of the expected caseload in January-February.
No reliable data
At the meeting, the experts made a presentation titled “Present COVID-19 immunity landscape in Karnataka and Bengaluru”. Quoting the presentation, TAC chairman M.K. Sudarshan told The Hindu that estimating the number of COVID-19 cases in the context of the emerging global trajectory, particularly with reference to China, is difficult at this point as no reliable and official data is available.
“However, it is generally believed that BF.7, a sub-variant of Omicron, may not trigger a wave as there is hybrid immunity (vaccine plus natural infection) in the population here. But stringent measures should be undertaken as a matter of precaution, and the evolution of the pandemic in the State has to be carefully studied for initiating further actions. We have requested these experts from IISc and ISI to study and give us a projection for the next two months in Karnataka,” Dr. Sudarshan said.
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“We have requested them to give us an estimate in a week as it will be helpful in pandemic management in terms of testing, beds, drugs and oxygen,” he said.
Minor XBB wave in Bengaluru
According to the TAC’s report, the experts in their presentation, said data and models suggested that there was a minor XBB wave in Bengaluru in November 2022. “Since the Omicron wave, case to infection ratios (CIR) have substantially increased worldwide, and the same is likely for Karnataka. The immunity landscape of Karnataka is that of a population with three doses plus infection either (BA.1/.2) in January-February 2022 or (BA.4/.5/2.75) in July-September 2022. These are perhaps the reasons for the low caseload and low severity,” according to their presentation.
“Data indicates that the immune escape of XBB is higher than that of other variants of concern BQ.1.1, BA.2.75.2, and BF.7. The variant BF.7 was detected in a few locations in July 2022 in India, but BA.5 and XBB variants still dominant. In Peru, Malaysia, Singapore, Indonesia, XBB overtook BQ.1, BA.5,” the presentation stated.
“The increased transmission in China and elsewhere will lead to the emergence of new variants. We should step up vaccination (for the newly eligible and for boosters) in the vulnerable districts, which could be identified from the paediatric serological survey. Clinical surveillance should also be intensified to track changes in symptoms apart from stepping up sequencing of severe cases at hospitals,” the experts advised.
They also suggested that a sentinel survey should be conducted — using the serosurvey protocol — for getting snapshots of infections and samples for sequencing. Neutralisation assay studies should also be done on sera sampled from the local population for precise understanding of the local immunity landscape, they said.