Hopes of Covid-19 herd immunity wane as surveillance systems collapse in Bengaluru

With Covid-19 cases surging in the state, hopes of herd immunity are waning even as fears of reinfection are growing. On top of this, the government's surveillance systems have collapsed.

On Tuesday, daily statewide numbers hit quadruple digits for the first time since December 25. One official blamed the surge in cases on the collapse of contact tracing and home isolation monitoring since the start of 2021. As per official data, in Bengaluru Urban, home isolation visits were done for only 53.3% of cases in the last seven days and no contacts were generated for 53.9% of new Covid-19 cases over the same period.

The noted epidemiologist Dr Giridhar Babu said this was due to personnel shortages prompted by the vaccine drive. “It has now been suggested to bring in personnel from all departments for the task,” he said.

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Another official stated that the Bruhat Bengaluru Mahanagara Palike (BBMP) was not entering the number of people traced in the central database while claiming that people had been traced.

"The problem is acute in Bengaluru," said Munish Moudgil, Director of the State Covid War Room.

“The simple reason is that people have stopped isolating patients. Once a person gets Covid-19 in a family, all in the family are getting Covid-19,” he said.

He rejected the notion that reinfections were also contributing to case increases.

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“The reality is that reinfections are negligible,” he said.

Hazy herd Immunity

Where does this leave the question of herd immunity? On the hazy ground, Health Minister Dr K Sudhakar said the results of the second seroprevalence study are still being tabulated.

“The preliminary results are expected only in one or two weeks. The second round will reveal if there has been a change in the pattern of the disease spread. We can also ascertain whether the districts with low prevalence then have seen the surge subsequently and if there is a need for further intervention to control the spread,” he said.

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As the survey’s principal investigator Dr Babu said it was too early to speak about herd immunity for Karnataka. To this, eminent virologist Dr T Jacob John, the former Professor of Clinical Virology, CMC Vellore, added that herd immunity is only possible if a community is isolated.

“If you have the free movement of people, no community immunity is possible,” he said.

He also disputed the extent of reinfections and their role in feeding the surge of cases.

“The disease has reached an endemic status in India and we are going to see periodic ups and downs in the number of cases. Reinfections are not causing these cases, it is the virus going through the vulnerable group of people who have not yet had the virus,” he said.