‘Number of people in Hyderabad with Covid antibodies could be much more than Sero-Survey results,’ says CCMB Director

The study, the largest seroprevalence survey taken up in the country with a sample size of over 10,000 persons in one city, revealed that around 54 per cent of the city’s residents have developed antibodies against SARS-CoV-2

Against the backdrop of the latest seroprevalence survey, which revealed that more than half of Hyderabad’s population have antibodies against the novel coronavirus, Dr. Rakesh Mishra, the Director of CSIR-Center for Cellular and Molecular Biology (CCMB) stressed the importance of the ‘social vaccine’ — wearing masks, maintaining personal hygiene and social distancing.

The study, the largest seroprevalence survey taken up in the country with a sample size of over 10,000 persons in one city, revealed that around 54 per cent of the city’s residents have developed antibodies against SARS-CoV-2, indicating prior exposure to the coronavirus. It also found that more than 75 per cent of the seropositive population did not know they had contracted the infection in the past.

Speaking to indianexpress.com, Dr. Mishra said that the actual percentage of Hyderabad’s population that developed antibodies against the virus could be much more. “Our data shows 54 per cent of samples had antibodies against COVID-19. We also saw that 90 per cent of people who tested positive had antibodies, which means 10 per cent did not. It means that people who have gone through the infection could be higher than that because some antibodies may disappear after 6 or 8 months and some may not generate antibodies. So 10 to 15 per cent may be missing in this way and the actual number might be more than 54 per cent. Considering these factors, we can extrapolate it to over 60 per cent,” said Dr. Mishra.

The samples were collected from 30 of the 150 wards of Greater Hyderabad over 12 days in the second half of January 2021 by researchers at ICMR–National Institute of Nutrition (NIN) and analysed by the scientists of CSIR–Centre for Cellular and Molecular Biology (CCMB) over the next couple of weeks. Indigenous vaccine developer Bharat Biotech, too, was part of the study. Karwan, in the old city of Hyderabad, was found to be one of the municipal wards with the highest seropositivity of over 71 per cent whereas Kanchanbagh, a locality with lesser population density, showed seropositivity of just over 30 per cent. “Most of the places had more or less around 50 per cent,” he said.

While according to him, the seropositivity found across the city through the survey was on expected lines and placed the city’s fight against COVID-19 at an advantageous position, it was not time to sit back and relax. “In our studies, we have found over 7000 virus mutations which may be of only academic interest. But it does not mean that certain combinations may not become nastier and bother us. There is a clear warning of danger although we have an upper hand at the moment. If suddenly there are large numbers of infections, new problems may emerge. It is a numbers game,” he said. Dr. Mishra noted that COVID-appropriate behaviour is the most impactful social vaccine against the virus.

If one out of two Hyderabadis have antibodies against the virus as the latest survey suggests, would that not discourage people from taking the vaccine jabs? Dr. Mishra said that was a wrong approach. “The vaccines are designed for robust and longer-lasting immunity, etc. There is no harm and they are not expensive. Even if you have some immunity, the vaccine will only boost that and make you stronger.”

Telangana continues to be in fear of the second wave of virus infections with surging numbers witnessed in neighbouring Maharashtra and Karnataka. The data as of March 4 puts the cumulative caseload in Telangana at 2,99,572. Currently, 1,963 of them are active and under treatment. As of March 5, the test positivity rate stands at 0.41 percent, the recovery rate is at 98.78 percent, and the case fatality ratio stands at 0.5 per cent. In the last seven days, according to the health department’s bulletin, the number of positive cases in Hyderabad has been between 25 and 30 cases per day. Medchal-Malkajgiri and Rangareddy districts adjoining Hyderabad are the only districts apart from Karimnagar that have recorded positive cases in double digits in the last week.

“We are in an advantageous position because the test positivity is low and the hospital situation is good. With seropositivity high, now if we go for vaccination in large numbers, and maintain covid appropriate behaviour of wearing masks and maintaining hygiene and social distancing, in three to four months we can defeat this virus,” Dr. Mishra pointed out, suggesting Hyderabad is inching closer to achieving herd immunity. For Bharat Biotech, which partnered in the survey, the study shows that the vaccine can be a decisive tool at the moment. “With such a level of seropositivity, the vaccine means to tilt the balance very heavily towards victory against this pandemic.”

According to the statistics available with the office of the Director of Public Health, as many as 5,05,542 persons have been vaccinated till March 4, 2021. Apart from 2,00,163 and 1,56,968 healthcare workers who have received the 1st and 2nd dose of the vaccination respectively to date, 49,762 beneficiaries in the category of elderly and persons with comorbidities have received the vaccine jabs. Similarly, 98,618 frontline workers have received the 1st dose and 31 have received the 2nd dose of the vaccine to date.

So, was the state’s strategy of testing only symptomatic patients and their contacts right? “In retrospect, we can say we somehow got away without much difficulty for a variety of reasons, but the state did what it could. We always feel it could have done more. More testing is knowing more. It enables you to take better decisions.” According to him, the population in entire Southeast Asia has become more resilient for a variety of reasons ranging from any prior experience of infections or low hygienic conditions that may have boosted immunity. “Of course, the government did take some crucial decisions like lockdown which gave time, and later, things have fallen in place.”

Earlier on February 9, the ICMR-NIN revealed its findings from the third round of sero-surveillance conducted in three districts of Telangana – Nalgonda, Jangaon, and Kamareddy, suggesting that one out of every four persons in the state had contracted the virus by the end of December 2020. This was part of the National Sero-survey conducted by the Indian Council of Medical Research (ICMR).

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