The Enigma of Low COVID-19 Fatality Rate in India

Abstract

Coronavirus disease 2019 (COVID-19), an acute onset pneumonia caused by a novel Betacoronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has rapidly evolved into a pandemic. Though its origin has been linked to the Wuhan City of China's Hubei Province in December 2019, recent reports claim that the original animalto-human transmission of the virus probably happened sometime between September and October 2019 in Guangdong Province, rather than Hubei. As of July 3, 2020, India has reported a case positivity rate of 6.5% and a fatality rate of 2.8%, which are among the lowest in the world. Also, the severity of the disease is much less among Indians as evidenced by the low rate of ICU admission (15.3%) and the need for mechanical ventilation (4.16%). As per the World Health Organization (WHO) situation report 165 on July 3, 2020, India has one of the lowest deaths per 100,000 population (1.32 deaths against a global average of 6.04). Several factors related to the pathogen, host and environment might have some role in reducing the susceptibility of Indians to COVID-19. These include some ongoing mutations that can alter the virulence of the circulating SARS-CoV-2 strains, host factors like innate immunity, genetic diversity in immune responses, epigenetic factors, genetic polymorphisms of ACE2 receptors, micro RNAs and universal BCG vaccination, and environmental factors like high temperature and humidity which may alter the viability and transmissibility of the strain. This perspective-highlights the potential factors that might be responsible for the observed low COVID-19 fatality rate in Indian population. It puts forward several hypotheses which can be a ground for future studies determining individual and population susceptibility to COVID-19 and thus, may offer a new dimension to our current understanding of the disease.

High prevalence of diabetes and other comorbidities in hospitalized patients with COVID-19 in Delhi, India, and their association with outcomes

“…India is home to the world’s second-largest population of diabetes (77 million) [ 9 , 10 ]. Interestingly the overall case fatality rate (CFR) of COVID-19 has remained low in India [ 11 ].…”

Demographic Profile of COVID-19 Cases: An Early Analysis of the Local Outbreak in a “Hotspot District” of Western Rajasthan in India

“…3 This is attributed to factors like innate immunity against previous bacterial and viral outbreaks, epigenetic factors, genetic polymorphisms of ACE2 receptors, and universal Bacillus Calmette-Guérin vaccination among the Indian population. 4 Also the viability and transmissibility of the virus is affected by hot and humid environmental conditions in the country. 4 Still, containment of the pandemic remains challenging in the country, owing to its inequalities in health infrastructure and education, socioeconomic and cultural disparities.…”

“…4 Also the viability and transmissibility of the virus is affected by hot and humid environmental conditions in the country. 4 Still, containment of the pandemic remains challenging in the country, owing to its inequalities in health infrastructure and education, socioeconomic and cultural disparities. 5 In order to stratify the endemicity of the infection, the Indian government has divided the 718 districts in the country into red, orange, and green zones, with red zone having the highest endemicity, and our locality has been marked as a red zone accordingly.…”

Perspectives About Modulating Host Immune System in Targeting SARS-CoV-2 in India

“…Thus, A2a variants could be important genetic variants for the development of effective vaccines and drugs against this virus. Further, sub-genotypes A3, A7, A1a, A2, and A6 have evolved from genotype A due to variation at the ORF1a, ORF3a, S, and nucleotide T514C respectively ( Samaddar et al, 2020 ). Another group in India has examined 591 different novel coronaviruses and grouped them in five different clades.…”