Genetic diversity and spatiotemporal distribution of SARS-CoV-2 alpha variant in India (preprint)

After the spill to humans, in the timeline of SARS-CoV-2, several positively selected variants have emerged. A phylogeographic study on these variants can reveal their spatial and temporal distribution. In December 2020, the alpha variant of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which has been designated as a variant of concern (VOC) by WHO, was discovered in the southeastern United Kingdom (UK). Slowly, it expanded across India, with a considerable number of cases, particularly in North India. The study focuses on determining the prevalence and expansion of the alpha variants in various parts of India. The genetic diversity estimation helped us understand various evolutionary forces that have shaped the spatial distribution of this variant during the peak. Overall, our study paves the way to understand the evolution and expansion of a virus variant.

The association of ABO blood group with the asymptomatic COVID-19 cases in India (preprint)

The COVID-19 pandemic has resulted several waves of infection in many countries worldwide. The large variations in case fatality ratio among different geographical regions suggests 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 shown 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 as well as blood groups among 509 random individuals from three major districts of Eastern Uttar Pradesh region of India.. Interestingly, we found neutralising antibodies in 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). This indicates that people with blood group AB are at comparatively higher risk of infection than other blood groups. Further, in line to previous reports we too observed that people with blood group O have significantly decreased risk of SARS-CoV-2 infection. Thus, among the asymptomatic SARS-CoV-2 infected individuals with blood group AB has highest, whilst blood group O has lowest risk of infection.

The Major Genetic Risk Factor for Severe COVID-19 Does Not Show Any Association Among Indian Populations (preprint)

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 50kb segment introgressed from Neanderthal adding a risk for COVID-19, and this trait is present among 16% and 50% people of European and South Asian origin respectively. Contrary to this finding, 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 ratio among South Asian populations. This result was also consistent with the realtime infection rate and case fatality ratio among various states of India. We readdressed this issue using both of the contrasting datasets and compared them with the realtime infection rates and case fatality ratio in India. We found out that the polymorphism present in the 50kb introgressed segment (rs10490770) did not show any significant correlation with the realtime infection and case fatality ratio in India.

Estimation of real-infection and immunity against SARS-CoV-2 in Indian populations (preprint)

Infection born by Coronavirus SARS-CoV-2 has swept the world within a time of a few months. It has created a devastating effect on humanity with social and economic depressions. Europe and America were the hardest hit continents. India has also lost several lives, making the country fourth most deadly worldwide. However, the infection and death rate per million and the case fatality ratio in India were substantially lower than many of the developed nations. Several factors have been proposed including the genetics. One of the important facts is that a large chunk of Indian population is asymptomatic to the SARS-CoV-2 infection. Thus, the real infection in India is much higher than the reported number of cases. Therefore, the majority of people are already immune in the country. To understand the dynamics of real infection as well as level of immunity against SARS-CoV-2, we have performed antibody testing (serosurveillance) in the urban region of fourteen Indian districts encompassing six states. In our survey, the seroprevalence frequency varied between 0.01-0.48, suggesting high variability of viral transmission among states. We also found out that the cases reported by the Government were several fold lower than the real infection. This discrepancy is majorly driven by a higher number of asymptomatic cases. Overall, we suggest that with the high level of immunity developed against SARS-CoV-2 in the majority of the districts, it is less likely to have a second wave in India.

The major genetic risk factor for severe COVID-19 among Europeans does not show any association among Indian populations (preprint)

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

Most frequent South Asian haplotypes of ACE2 share identity by descent with East Eurasian populations (preprint)

It was shown that the human 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 whole genome data of World populations focusing South Asia. Genetically, South Asians are more related with the West Eurasian populations rather than East Eurasians. Whereas, for this gene, unexpectedly South Asians are more closer to East Eurasians rather than West Eurasians. The phylogenetic analysis suggested that the majority of South Asian haplotypes are shared with the East Eurasians in the background of two unique event polymorphisms which are responsible for this attraction. The second SNP rs2285666 has marked difference among South Asian vs European/American. Hence, it is highly likely that among the South Asians, the host susceptibility to the  novel coronavirus SARS-CoV-2 will be more similar to East/Southeast Asians rather than the Europeans.