Introduction Coronavirus Disease-2019 (SARS-CoV-2) started its devastating trajectory into a global pandemic in Wuhan, China, in December 2019. Ever since, several variants of SARS-CoV-2 have been identified. In the present review, we aimed to characterize the different variants of SARS-CoV-2 and explore the related morbidity and mortality. Methods A systematic review including the current evidence related to different variants of SARS-CoV-2 and the related morbidity and mortality was conducted through a systematic search utilizing the keywords in the online databases including Scopus, PubMed, Web of Science, and Science Direct; we retrieved all related papers and reports published in English from December 2019 to September 2020. Results A review of identified articles has shown three main genomic variants, including type A, type B, and type C. we also identified three clades including S, V, and G. Studies have demonstrated that the C14408T and A23403G alterations in the Nsp12 and S proteins are the most prominent alterations in the world, leading to life-threatening mutations.The spike D614G amino acid change has become the most common variant since December 2019. From missense mutations found from Gujarat SARS-CoV-2 genomes, C28854T, deleterious mutation in the nucleocapsid (N) gene was significantly associated with patients' mortality. The other significant deleterious variant (G25563T) is found in patients located in Orf3a and has a potential role in viral pathogenesis. Conclusion Overall, researchers identified several SARS-CoV-2 variants changing clinical manifestations and increasing the transmissibility, morbidity, and mortality of COVID-19. This should be considered in current practice and interventions to combat the pandemic and prevent related morbidity and mortality.

Introduction: Patients with COVID-19 may present different viral loads levels. However, the relationship between viral load and disease severity in COVID-19 is still unknown. Therefore, this study aimed to systematically review the association between SARS-CoV-2 viral load and COVID-19 severity. Methods: The relevant studies using the keywords of "COVID-19" and "viral load" were searched in the databases of PubMed, Scopus, Google Scholar, and Web of Science. A two-step title/abstract screening process was carried out and the eligible studies were included in the study. Results: Thirty-four studies were included from the initial 1015 records. The vast majority of studies have utilized real-time reverse transcriptionpolymerase chain reaction of the nasopharyngeal/respiratory swabs to report

Introduction COVID-19 vaccines emerged as a worldwide hope to contain the pandemic. However, many people ‎are still hesitant to receive these vaccines. We aimed to systematically review the public knowledge, perception, and acceptability of COVID-19 vaccines in the Middle East and North Africa (MENA) countries and the predictors of vaccine acceptability in this region. Methods We systematically searched databases of PubMed, Scopus, Web of Science, and Cochrane and retrieved ‎all relevant studies by 5 August 2021. Results There was a considerable variation in the COVID-19 vaccine acceptance ‎rates, from 12% in a study from Israel to 83.3% in Kuwait, although two other studies from Israel mentioned 75% ‎and 82.2% acceptability rates. Concerns about the side effects and safety of the vaccine were the main reasons for ‎the lack of acceptability of taking the vaccine, which was reported in 19 studies. ‎ Conclusion Several factors, such as age, gender, education level, and comorbidities, ‎are worthy of attention as they could expand vaccine coverage in the target population.‎