Estimation of real COVID-19 cases in India during the first wave.

In 2020, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread across the world within a few months. The SARS-CoV-2 pandemic has had a devastating effect on humanity, with social and economic consequences. The continents of Europe and America have been hit the hardest. However, there has also been a huge loss of life in India, with the country having the fourth highest number of total deaths worldwide. Nevertheless, the infection and death rates per million and the case fatality ratio in India are substantially lower than those in many developed nations. Several explanations for this have been proposed, including genetics. Mathematical modelling has suggested that the actual number of infections is much higher than the number of reported cases. Therefore, to understand the dynamics of actual infection and the population-level immunity against SARS-CoV-2, a serosurvey (antibody testing) was performed among 2301 individuals in urban regions of 14 districts in six states of India. A notable outcome of this study was that a large proportion of the Indian population had an asymptomatic SARS-CoV-2 infection. The real infection rate in India was several fold higher than the reported number of cases. Therefore, a large number of people in the country have developed SARS-CoV-2-specific antibodies. In this survey, the seroprevalence (frequency antibody-positive) varied between 0.01 (95% CI 0.002-0.054) and 0.477 (95% CI 0.392-0.563), suggesting a high variability in viral transmission between the states and the possibility of future waves. In this study population, the frequency of asymptomatic infection was highest in the younger age groups. It was also found that the numbers of cases reported by the government were several-fold lower than the real incidence of infection. It is likely that the high number of asymptomatic cases was the main driver of this discrepancy.

Studying C-reactive protein and D-dimer levels in blood may prevent severe complications: A study in Bangladeshi COVID-19 patients.

The ongoing COVID-19 pandemic has been a scientific, medical and social challenge. Since clinical course of this disease is largely unpredictable and can develop rapidly causing severe complications, it is important to identify laboratory biomarkers, which may help to classify patient's severity during initial stage. Previous studies have suggested C-reactive protein (inflammatory) and D-dimer (biochemical) as an effective biomarker. The differential severity in patients across the world and our limited understanding in the progression of the disease calls for a multi-country analysis for biomarkers. Therefore, we have analyzed these biomarkers among 228 Bangladeshi COVID-19 patients. We observed significant association of COVID-19 severity with these two biomarkers. Thus, we suggest to use these biomarkers for Bangladeshi COVID-19 patients for better disease monitoring. Such validated preventive measures may decrease the case fatality ratio substantially.

Vaccine hesitancy for coronavirus SARS-CoV-2 in Varanasi India

With the rollout of the world's largest vaccine drive for SARS-CoV-2 by the Government of India on January 16 2021, India had targeted to vaccinate its entire population by the end of 2021. Struggling with vaccine procurement and production earlier, India overcome these hurdles, but the Indian population still did not seem to be mobilizing swiftly toward vaccination centers. The severe second wave has slowed the vaccination pace and was also one of the major contributing factors to vaccine hesitancy. To understand the nature of vaccine hesitancy and its underlying factors, we conducted extensive online and offline surveys in Varanasi and adjoining regions using structured questions. Most respondents were students (0.633). However, respondents from other occupations, such as government officials (0.10), have also participated in the study. Interestingly, most people (0.75) relied on fake news and did not take COVID-19 seriously. Most importantly, we noticed that a substantial proportion of respondents (relative frequency 0.151;mean age 24.8 years) reported that they were still not interested in vaccination. We observed a significant association between vaccine hesitancy and socioeconomic status (χ2 = 307.6, p < 0.001). However, we failed to detect any association between vaccine hesitancy and gender (χ2 = 0.007, p > 0.5). People who have neither been vaccinated nor have ever been infected may become the medium for spreading the virus and creating new variants, which may lead to the vaccine-resistant variant. We expect this extensive survey to help the Government upgrade their vaccination policies for COVID-19 in North India.

Genetic association of TMPRSS2 rs2070788 polymorphism with COVID-19 case fatality rate among Indian populations.

SARS-CoV-2, the causative agent for COVID-19, an ongoing pandemic, engages the ACE2 receptor to enter the host cell through S protein priming by a serine protease, TMPRSS2. Variation in the TMPRSS2 gene may account for the disparity in disease susceptibility between populations. Therefore, in the present study, we have used next-generation sequencing (NGS) data of world populations from 393 individuals and analyzed the TMPRSS2 gene using a haplotype-based approach with a major focus on South Asia to study its phylogenetic structure and their haplotype sharing among various populations worldwide. Our analysis of phylogenetic relatedness showed a closer affinity of South Asians with the West Eurasian populations therefore, host disease susceptibility and severity particularly in the context of TMPRSS2 will be more akin to West Eurasian instead of East Eurasian. This is in contrast to our prior study on the ACE2 gene which shows South Asian haplotypes have a strong affinity towards West Eurasians. Thus ACE2 and TMPRSS2 have an antagonistic genetic relatedness among South Asians. Considering the significance of the TMPRSS2 gene in the SARS-CoV-2 pathogenicity, COVID-19 infection and intensity trends could be directly associated with increased expression therefore, we have also tested the SNPs frequencies of this gene among various Indian state populations with respect to the case fatality rate (CFR). Interestingly, we found a significant positive association between the rs2070788 SNP (G Allele) and the CFR among Indian populations. Further our cis eQTL analysis of rs2070788 shows that the GG genotype of the rs2070788 tends to have a significantly higher expression of TMPRSS2 gene in the lung compared to the AG and AA genotypes thus validating the previous observation and therefore it might play a vital part in determining differential disease vulnerability. We trust that this information will be useful in understanding the role of the TMPRSS2 variant in COVID-19 susceptibility and using it as a biomarker may help to predict populations at risk.

COVID-19: Impact on linguistic and genetic isolates of India.

The rapid expansion of coronavirus SARS-CoV-2 has impacted various ethnic groups all over the world. The burden of infectious diseases including COVID-19 are generally reported to be higher for the Indigenous people. The historical knowledge have also suggested that the indigenous populations suffer more than the general populations in the pandemic. Recently, it has been reported that the indigenous groups of Brazil have been massively affected by COVID-19. Series of studies have shown that many of the indigenous communities reached at the verge of extinction due to this pandemic. Importantly, South Asia also has several indigenous and smaller communities, that are living in isolation. Till date, despite the two consecutive waves in India, there is no report on the impact of COVID-19 for indigenous tribes. Since smaller populations experiencing drift may have greater risk of such pandemic, we have analysed Runs of Homozygosity (ROH) among South Asian populations and identified several populations with longer homozygous segments. The longer runs of homozygosity at certain genomic regions may increases the susceptibility for COVID-19. Thus, we suggest extreme careful management of this pandemic among isolated populations of South Asia.

The association of ABO blood group with the asymptomatic COVID-19 cases in India.

The COVID-19 pandemic resulted in multiple waves of infection worldwide. The large variations in case fatality rate among different geographical regions suggest that the human susceptibility against this virus varies substantially. Several studies from different parts of the world showed a significant association of ABO blood group and COVID-19 susceptibility. It was demonstrated that individuals with blood group O are at the lower risk of coronavirus infection. To establish the association of ABO blood group in SARS-CoV-2 susceptibility, we for the first time analysed SARS-CoV-2 neutralising antibodies among 509 individuals, collected from three major districts of Eastern Uttar Pradesh region of India. Interestingly, we found neutralising antibodies in a significantly higher percentage of people with blood group AB (0.36) followed by B (0.31), A (0.22) and lowest in people with blood group O (0.11). We further estimated that people with blood group AB are at comparatively higher risk of infection than other blood groups. Thus, among the asymptomatic SARS-CoV-2 recovered people blood group AB has highest, whilst individuals with blood group O has lowest risk of infection.

The major genetic risk factor for severe COVID-19 does not show any association among South Asian populations.

With the growing evidence on the variable human susceptibility against COVID-19, it is evident that some genetic loci modulate the severity of the infection. Recent studies have identified several loci associated with greater severity. More recently, a study has identified a 50 kb genomic segment introgressed from Neanderthal adding a risk for COVID-19, and this genomic segment is present among 16% and 50% people of European and South Asian descent, respectively. Our studies on ACE2 identified a haplotype present among 20% and 60% of European and South Asian populations, respectively, which appears to be responsible for the low case fatality rate among South Asian populations. This result was also consistent with the real-time infection rate and case fatality rate among various states of India. We readdressed this issue using both of the contrasting datasets and compared them with the real-time infection rates and case fatality rate in India. We found that the polymorphism present in the 50 kb introgressed genomic segment (rs10490770) did not show any significant correlation with the infection and case fatality rate in India.

Genetic Association of ACE2 rs2285666 Polymorphism With COVID-19 Spatial Distribution in India.

Studies on host-pathogen interaction have identified human ACE2 as a host cell receptor responsible for mediating infection by coronavirus (COVID-19). Subsequent studies have shown striking difference of allele frequency among Europeans and Asians for a polymorphism rs2285666, present in ACE2. It has been revealed that the alternate allele (TT-plus strand or AA-minus strand) of rs2285666 elevate the expression level of this gene upto 50%, hence may play a significant role in SARS-CoV-2 susceptibility. Therefore, we have first looked the phylogenetic structure of rs2285666 derived haplotypes in worldwide populations and compared the spatial frequency of this particular allele with respect to the COVID-19 infection as well as case-fatality rate in India. For the first time, we ascertained a significant positive correlation for alternate allele (T or A) of rs2285666, with the lower infection as well as case-fatality rate among Indian populations. We trust that this information will be useful to understand the role of ACE2 in COVID-19 susceptibility.

Most frequent South Asian haplotypes of ACE2 share identity by descent with East Eurasian populations.

It was shown that the human Angiotensin-converting enzyme 2 (ACE2) is the receptor of recent coronavirus SARS-CoV-2, and variation in this gene may affect the susceptibility of a population. Therefore, we have analysed the sequence data of ACE2 among 393 samples worldwide, focusing on South Asia. Genetically, South Asians are more related to West Eurasian populations rather than to East Eurasians. In the present analyses of ACE2, we observed that the majority of South Asian haplotypes are closer to East Eurasians rather than to West Eurasians. The phylogenetic analysis suggested that the South Asian haplotypes shared with East Eurasians involved two unique event polymorphisms (rs4646120 and rs2285666). In contrast with the European/American populations, both of the SNPs have largely similar frequencies for East Eurasians and South Asians, Therefore, it is likely that among the South Asians, host susceptibility to the novel coronavirus SARS-CoV-2 will be more similar to that of East Eurasians rather than to that of Europeans.