Gender and genetic factors impacting COVID-19 severity.

COVID-19 pandemic is a cause of global concern and is impacting lives and economy globally. Infection due to SARS-CoV-2 leads to varied clinical manifestations, which can vary from asymptomatic to severe acute respiratory syndrome and death. The clinical features are proposed to depend upon various host factors, namely, gender and genetic factors. The significantly high mortality among males has revealed the role of gender, androgens, age, genetics, and risk factors in determining the severity of COVID-19 among the population. The interplay of various host factors and their association with clinically severe infections is crucial for our understanding of COVID-19 pathogenesis. A PubMed and Google scholar search was made using keywords such as "COVID-19 + sex differences," "COVID-19 + androgens," "COVID-19 + ACE2 receptor," and "COVID-19 + smoking alcoholism pregnancy." The articles which highlight the association of gender and genetic factors to COVID-19 were selected and included in our study. It is mainly the primary care or family physicians who act as the first contact of COVID-19 patients. With the recent increase in SARS-CoV-2 infections in the Indian subcontinent and probability of upcoming surges, it has become imperative to understand its interaction with the various gender and genetic factors to devise effective triage and management protocols. Our review highlights the possible mechanisms by which these factors impact the severity of COVID-19. A better understanding of these factors will be of immense help to primary care physicians.

Comparison of Cycle Threshold and Clinical Status Among Different Age Groups of COVID-19 Cases.

Introduction The COVID-19 pandemic has shaken the entire world ever since its emergence in March 2020. The disease manifestation of COVID-19 has been more severe, with a high degree of mortality in the elderly than in the young population. The cycle threshold (Ct ) value obtained in the real-time polymerase chain reaction (RT-PCR) has been used as the surrogate marker of viral load. Therefore, assessing Ct value and clinical status among different age groups with SARS-CoV-2 infection is required to understand the viral kinetics and to assess the transmission potential of that particular age group. Purpose The aim of this study was to compare the viral load and clinical status among different age groups with COVID-19 infection. Methods and materials A retrospective cross-sectional study was carried out to analyze the Ct values of SARS-CoV-2 positive samples reported from April 2020 till May 2021. The results of 13,820 RT-PCR (reverse transcriptase-polymerase chain reaction) positive samples were included for analysis of Ct values. Ct values of confirmatory genes were taken into consideration, and Ct values below 25, >25 to 30, and >30 were categorized as high, moderate, and low viral load, respectively. Age group was stratified into ≤18 years (young), 18-60 years (adult), and >60 years (elderly). The data were analyzed using SPSS Windows Version 25.0. Results The mean Ct values were 27.9, 26, and 26.2 in the young, adult, and elderly age groups, respectively. The mean Ct values of young patients were significantly higher as compared to adult and elderly patients (p<0.05). The percentage of high viral load (Ct<25) was found to be significantly higher in adults and elderly (44.6% & 43.7%) as compared to young (32.2%) (p<0.001). Majority of the COVID-19 positive cases younger than 18 years (75.9%) were asymptomatic as compared to 64.5% and 59.7% in the adult and elderly age groups, respectively. Conclusion This study observed a significantly high proportion of viral load in the adult and elderly population, which plays a substantial contribution to SARS-CoV-2 transmission, whereas the majority of the young population being asymptomatic plays a major role as silent transmitters. The study reemphasizes the need for strict adherence to COVID-appropriate behaviors.

High proportion of low cycle threshold value as an early indicator of COVID-19 surge.

Many countries in the world are experiencing a recent surge in COVID-19 cases. This is mainly attributed to the emergence of new SARS-CoV-2 variants. Genome sequencing is the only means to detect the evolving virus mutants and emerging variants. Cycle threshold values have an inverse relationship with viral load and lower Ct values are also found to be associated with increased infectivity. In this study, we propose to use Ct values as an early indicator for upcoming COVID-19 waves. A retrospective cross-sectional study was carried out to analyze the Ct values of positive samples reported during the first wave and second wave (April 2020-May 2021). Median Ct values of confirmatory genes were taken into consideration for comparison. Ct values below 25, >25-30, and >30 were categorized as high, moderate, and low viral load respectively. Our study found a significantly higher proportion of positive samples with a low Ct value (<25) across age groups and gender during the second wave of the COVID-19 pandemic. A higher proportion of positive samples with a low Ct value (high viral load) may act as an early indicator of an upcoming surge.

Intricacies in characterizing positivity in pooled sample testing for SARS-CoV-2.

The unprecedented demand for testing for the ongoing coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 has led to an acute shortage and limited availability of test reagents for which pooling of samples has been recommended in areas with low prevalence. Considering the possibility of dilution factor in pool testing, an attempt was made to find out possibility of any true positive samples in pools with late amplification. The study was conducted on samples received from various collection centers in different districts of Odisha as well as from patients attending the screening clinic or admitted in COVID ward of the hospital. Nasal/nasopharyngeal/throat swabs received in viral transport media in cold chain were subjected to Real-time polymerase chain reaction (RT-PCR) testing in a Biosafety Laboratory level-2 by including uniform volume of four units (samples) per pool. All confirmed and probable positive pools in screening assay were de-convoluted and individual samples tested for confirmatory assay. Inclusion of an additional criteria of probable positive pool (Ct value >35 with non-sigmoid amplification curve or showing a line of amplification towards the end of the cycle) yielded 39 (15.5%) more true positive samples out of a total of 251 positive samples that would otherwise have been missed if only the classical criteria of positive (Ct within 35 with proper sigmoid curve) had been considered. The study highlights the importance of considering any indication of late amplification in the RT-PCR test to label a pool as positive to avoid missing any true positive sample in the pool.