Published: 24th July 2021
Experts say larger population surveys required for understanding of COVID-19 antibody response
Experts also suggest that the presence of antibodies does not guarantee 100 per cent protection against COVID-19 infection
After the release of the fourth round of the National Sero Survey results, health experts believe that larger population surveys are required for a deeper understanding of COVID-19 and its antibody response. The Union Health Ministry on Tuesday informed that the fourth round of the National Sero Survey has been conducted and the overall seroprevalence in the country is at 67.6 per cent. Dr Rahul Tambe, Senior Consultant, Internal Medicine and Infectious Disease, Nanavati Max Super Speciality, Mumbai said, "Although over 28,975 residents and 7,252 healthcare workers were a part of the sero-surveillance, larger population surveys are required for deeper understanding of COVID-19 and antibody response. Residents should continue to remain cautious about disease spread because we are still unaware about the incidence rate of different variants and its co-relation with antibody response. Most importantly, the presence of antibodies does not guarantee 100 per cent protection against COVID infection. So as aptly communicated by ICMR, though the results are a ray of hope, there is no room for complacency."
The fourth round of national serosurvey was conducted in 70 districts in June-July and significantly it included children between 6-17 years of age, according to Union Health Ministry. In unvaccinated, the seroprevalence was 62.3 per cent and with one dose of vaccine, it was 81 per cent. In those who received both doses, it was 89.8 per cent. Dr Sonam Solanki, Pulmonologist and Bronchoscopist, Wockhardt Hospital, Mumbai stressed for aggressive vaccination drive. "The study conducted in 70 districts across 21 states showed similar results in both urban and rural areas. Even though our current recorded daily cases are low, we still have 40 crore people who are vulnerable to COVID-19 infection and 50 per cent of children who do not have antibodies. Instead of becoming relaxed looking at the numbers and relaxation of the lockdown, aggressive vaccination drive should be our focus," Dr Solanki said.
Various health experts shed light on the fact that 10 per cent of the healthcare workers are still not vaccinated and that gap needs to be covered immediately. Dr Soumik Goswami, Faculty, Department of Endocrinology, NRS Hospital, Kolkata said, "Matter is still very serious because even if 10 per cent of those 40 crores were infected that amounts to 4 crores and if one per cent of those four crores requires hospitalisation that will create a huge demand on our infrastructure. Hence there is no room for complacency." The trend of the last few days shows overall cases have plateaued in India but has not actually dipped. Unless the vaccination rate goes up, it would be difficult to tackle the mortality, Dr Goswami observed. "Moreover it is a sample survey that took around 35,000 individuals from a country of 136 crore individuals so it may not reflect the reality across all parts of the country," pointed out Dr Goswami.
Implications of the fourth serosurvey clearly show that there is a ray of hope but there is no room for complacency, the Indian Council of Medical Research (ICMR) observes. Earlier, ICMR Director-General Dr Balram Bhargava had informed about the third national serosurvey that was conducted before vaccination started, in the period between December 17, 2020 and January 8, 2021. At that time, overall seroprevalence was 21.5 per cent of the population, which includes 31.7 per cent of urban slums, 26.2 per cent of urban non-slum and 19.1 per cent of rural areas.