HLA is crucial for appropriate immune responses in several viral infections, as well as in severe acute respiratory syndrome coronavirus‐2 (SARS CoV‐2). The unpredictable nature of Coronavirus Disease 19 (COVID‐19), observed in both inter‐individual and inter‐population level, raises the question, to what extent the HLA, as part of host genetic factors, contribute to disease susceptibility and prognosis. We aimed to identify significant HLAs, those were investigated till now, for their association with COVID‐19. Three databases were searched (PubMed, Cochrane library, and Web of Science) and articles published between January 2020 and May 2021 were included for in‐depth analysis. Two separate teams including four observers independently extracted the summary data, with discrepancies resolved by consensus. This study is registered with PROSPERO (CRD42021251670). Of 1278 studies identified, 36 articles were included consisting of 794,571 participants. Countries from the European region appeared in the highest number of studies and vice versa for countries from South East Asia. Among 117 significantly altered alleles, 85 (72.65%) were found to have a positive correlation with COVID‐19 and 33 (27.35%) alleles were observed having a negative correlation. HLA A*02 is the most investigated allele (n = 18) and showed contradictory results. Non‐classical HLA E was explored by only one study and it showed that E*01:01 is associated with severity. Both in silico and wet lab data were considered and contrasting results were found from two approaches. Although several HLAs depicted significant association, nothing conclusive could be drawn because of heterogeneity in study designs, HLA typing methods, and so forth. This systematic review shows that, though HLAs play role in COVID‐19 susceptibility, severity, and mortality, more uniformly designed, interrelated studies with the inclusion of global data, for use in evidence‐based medicine are needed.

Antibiotic resistance management is a challenging task in Low and Middle-Income Countries (LMICs) such as Bangladesh. Improper regulation and uncontrolled spreading of Antibiotic Resistant Genes (ARGs) from LIMCs pose a great threat to global public health. The human gut microbiome is a massive reservoir of Antibiotic Resistant Genes (ARGs). In this study, we unraveled the ARGs in the gut microbiome of the Bangladeshi population and compared them with several other countries around the world. Here, 31 fecal samples from different ethnic groups living in Bangladesh namely Bengali (n=9), Chakma (n=6), Khyang (n=5), Marma (n=6), and Tripura (n=5) were collected. Shotgun metagenomic sequencing method was implemented for revealing the ARGs. The resistome profiling was executed on three levels-the total microbiome, the plasmidome, and the virome. In all three levels, samples from Bangladeshi cohorts showed higher ARG profiles compared to foreign samples. On average, the number of ARGs in the Bangladeshi samples ranged between 75.11 and 88. Among them, class C beta-lactamases, quinolone resistance genes, and tetracycline efflux pumps were relatively more abundant. Additionally, the MexPQ-OpmE drug resistance pathway was found to be more prevalent. Findings from our study suggest that the spread of antibiotic resistance within the Bangladeshi population is being facilitated by the gut microbiome especially via the mobilome. Therefore, strict regulation on antibiotic usage is necessary to halt the spread of ARGs.

Human gut microbiome is influenced by ethnicity and other factors. In this study, we have explored the gut microbiome of Bengali population (n=13) and four Tibeto-Burman indigenous communities- Chakma (n=15), Marma (n=6), Khyang (n=10), and Tripura (n=11) using 16S rRNA amplicon sequencing. A total of 19 characterized phyla were identified in 5 cohorts, with Firmicutes and Bacteroidetes being the most prevalent. At the genus level, the abundance of Prevotella was relatively similar across all ethnicities. However, the Chakma population demonstrated higher Bacteroides abundance. Chakma people were more distinct than other ethnicities and exhibited a higher quantity of differentially abundant microbial features. The Bengali population had relatively low bacterial richness and Firmicutes to Bacteroidetes ratio than others with lower qualitative microbial diversity. A phylosymbiotic link between Bangladeshi indigenous people and certain ethnic groups in India have also been discovered. A comparative analysis between all Bangladeshi samples (n=55) and several tropical and subtropical countries (n=132) such as Australia, Egypt, Indonesia, Malaysia, Mexico, Thailand, and Vietnam revealed that the gut microbiota profile of Bangladeshi people is remarkably distinct from others. The insights from this study will aid further epidemiological and translational research.