BENGALURU: While Karnataka grapples with the fear of an anticipated third wave of Covid-19, the State Government’s most important report on serosurveillance data — which helps the state predict the impact of the third wave — is lying in cold storage.
The reasons, according to sources, is that the seroprevalence in Karnataka is as low as 14 per cent, which is way lower than the first serosurveillance, which showed the seroprevalence at 27 per cent.
“The survey, which started towards January-end, was completed by March and analysed by April. They realised that seroprevalence in the state was less than what it was in the earlier survey. A sub-survey in May has also been analysed and the findings submitted to the government,” a senior doctor, who is part of the expert committee set up by the government to manage Covid- 19, said. Karnataka’s sero-survey data actually goes against the ICMR theory that states are showing good seroprevalence.
This could be one of the reasons the results of the survey have not yet been announced, the senior doctor said. However, another expert, who requested anonymity, said the report submitted to the State Government has added the findings of the two seroprevalence surveys to show an increase in presence of antibodies among a good section of the population in Karnataka.
No two sero surveys can be compared, says expert
“The data of the second survey is with the government. It is expected to release the data soon,” Dr V Ravi, renowned virologist and part of the technical advisory committee to the government, said.
On adding the seroprevalence data of the two surveys, he said: “Sero-surveys are additive because our design did not include population from the first round. This is over and above the first round. We have used the same kind of tests too.” But he did not comment on whether the report submitted to the government had done this kind of analysis.
On the other hand, Dr Tarun Bhatnagar, scientist at the Indian Council for Medical Research (ICMR), who was part of the recently released sero-survey report by ICMR, told The New Indian Express, “I haven’t seen the sero-report by Karnataka yet. But definitely we cannot add the two surveys. The thing is, depending on the gap between two surveys, there is natural waning of antibodies. So, even those who were antibody positive in the first survey, will show it waned. Even if the samples are of two different people, we cannot add it, as in general, antibodies would wane over time. We have to take whatever it is at that time as final.”
Dr Gagandeep Kang, renowned virolgist and Prof of Microbiology with CMC Vellore, in a recent interview with TNIE, had said, “A lot depends on the test. If you use a poor test, you will have lower seropositivity. If you use a test that shows false positivity, then you will have very high sero-positivity. But no two surveys are comparable with each other if they are not the same test.”
On the recent sero report by ICMR, Dr Ravi said the results are encouraging, but one should not be complacent. “Sero survey tells you that antibodies are present, but that is not directly equivalent to protection. Important attribution to protection is vaccination. Up to 60 per cent of the adult population is still not vaccinated. You can have antibodies, but if there is a new variant, it is dangerous. We must expect and prepare for any future waves.”
Considering that around 45 crore population is still vulnerable and that even if 80 per cent come down with infection it means around 35 crore people would be infected, he pointed out. “If 5 to 10 per cent of them develop severe infection, then imagine the mayhem that will be created. So, until 75-80 per cent vaccination coverage is reached, we cannot relax,” he stressed.
Health Minister Dr K Sudhakar could not be reached for comment despite several attempts. But Health Commissioner Dr K V Thrilok Chandra said the survey report will be released by this weekend or early next week, and that the details will be disclosed then.