After India’s brutal coronavirus wave, two-thirds of population has been exposed to SARS-CoV2
A public health scholar based in New Delhi explains how India has emerged from the massive spike in COVID-19 cases, even as the country braces for a new wave.
24 August 2021 – by Rajib Dasgupta
Cases of COVID-19 are surging around the world, but the course of the pandemic varies widely country to country. To provide you with a global view as we approach a year and a half since the official declaration of the pandemic, The Conversation’s editors from around the world commissioned articles looking at specific countries and where they are now in combating the pandemic.
Here, Rajib Dasgupta from the Centre of Social Medicine and Community Health at Jawaharlal Nehru University in New Delhi writes about India following its devastating wave of infections earlier in 2021. You can see the whole collection of articles here.
What explains the rapid spike and then sharp decline of cases of the April-to-June wave?
Both the alpha and delta variants are highly contagious, with delta being nearly twice as transmissible as the original strain of SARS-CoV-2. The rapid rise in cases in India is attributed to the high viral load – the amount of virus infecting a person – of delta, which is about 1,000 times higher than other strains. This resulted in widespread infections among household members with rates as as high as 80% to 100%.
How many of India’s 1.3 billion people have been infected?
In the aftermath of the second wave from roughly April to June, the Indian Council of Medical Research conducted the fourth round of a national sero-survey in June and July 2021 to test for antibodies in blood samples from residents across 70 districts of 21 states. The overall sero-prevalence was 67.6%, a huge increase from 24.1% recorded in the third round from December, 2020 to January, 2021. The presence of antibodies indicates that a person has either been exposed to the coronavirus or has been vaccinated.
Sero-positivity among children was 57.2% in those aged 6-9 years and 61.6% among those who are 10-17 years old. Experts believe that there is not much scientific evidence that children would be disproportionately vulnerable in a third wave. The government, however, anticipates the possibility of intermittent surges in the number of cases and prepared operational guidelines for children and adolescents in preparation for a third wave. Seroprevalence among those above 45 years was 77.6% and 66.7% among younger adults, indicating the effect of vaccination as well as infections.
The coronavirus had spread through the entire country; seroprevalence among the rural population (66.5%) was only slightly lower than in urban counterparts. A wide range of interstate differences have emerged, from a low of 44.4% in Kerala to 79% in Madhya Pradesh.
The extent of undercount – the difference between estimated cases (based on seroprevalence) and actual cases detected by RT-PCR and rapid antigen tests – is particularly worrying. Nationally, the system missed 33 cases for every one detected.
COVID-19 vaccination in India has been marked by both inequity and hesitancy; negotiating both will be crucial in the weeks ahead.
The range of vulnerabilities have included rural and remote locations and a lack of access to the internet; a gender divide has emerged too with more men being vaccinated than women. As vaccination progresses with underlying inequities, the phenomenon of “patchwork vaccination” emerges – pockets that are highly vaccinated and adjacent to places or communities with low coverage. The communities with low coverage are vulnerable to hyperlocal outbreaks.
Most economic activities have resumed, and the education and entertainment sectors are opening up too. A joint statement on June 6, 2021, issued by the public health associations in India urged that district-level sero-surveys be undertaken by the state or federal health services to enable a more granular understanding of the epidemiologic context to enable planning. While this was accepted in principle, such systematic surveys have yet to be rolled out.
The World Health Organization advises that public health and social measures in the context of COVID-19 be guided by local transmission dynamics. Planning at the district level in India shall be crucial in the journey ahead.