ABSTRACT
Background: The world has been suffering from the COVID-19 pandemic (officially declared by WHO in March 2020), caused by the severe acute respiratory ß-coronavirus 2 (SARS-CoV-2) since the last week of December 2019. The disease was initially designated as a Public Health Emergency of International Concern on January 30, 2020. In order to protect the health of mass public, an array of research on drugs and vaccines against SARS-CoV-2 has been conducted globally. However, the emerging variants of SARS-CoV-2, i.e., Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) variants which evolved in late 2020 and the Omicron variant (B.1.1.529) which emerged in November 2021 along with its subvariant BA.2 which was first identified in India and South Africa in late December 2021, have raised the doubt about the efficiency of the currently used vaccines especially in terms of the consistent potential to produce neutralizing antibodies targeting the viral spike (S) protein. Main body of the abstract: The present review discussed the functional details of major vaccines regarding their efficiency against such variants during the pandemic. Overall, the mRNA vaccines have shown around 94% effectiveness; the adenovector vaccine showed approximately 70% efficacy, whereas Sputnik V vaccines showed around 92% effectiveness; the inactivated whole-virus vaccine CoronaVac/PiCoVacc and BBIBP-CorV showed a varying effectiveness of 65-86% according to the geographic locations; the subunit vaccine NVX-CoV2373 has shown 60-89% effectiveness along with the global regions against the wild-type SARS-CoV-2 strain. However, reduced effectiveness of these vaccines against the SARS-CoV-2 variants was noticed which is suggestive for the further administration of booster dose. Short conclusion: Maximum variants of SARS-CoV-2 emerged during the second wave of COVID-19; and extensive studies on the viral genomic sequences from all geographical locations around the world have been conducted by an array of groups to assess the possible occurrence of mutations(s) specially within the receptor binding domain of the viral spike (S) protein. Mutational similarities and the new or critical mutations within all variants have been clearly identified so far. The study of effectiveness of the currently used vaccines is also ongoing. The persistence of memory B cell action and the other immune components as well as the administration of booster dose is expected to mitigate the disease.
ABSTRACT
INTRODUCTION: The COVID-19 pandemic has exacerbated health inequalities across the globe, disproportionately affecting those with poor social determinants of health (SDOHs). It is imperative to understand how SDOH influences the transmission and outcomes (positive case, hospitalisation and mortality) of COVID-19. This systematic review will investigate the impact of a wide range of SDOHs across the globe on the transmission and outcomes of COVID-19. METHODS AND ANALYSIS: This review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines. We will search three electronic bibliographical databases (MEDLINE via PubMed, Embase and Scopus), as well as the WHO COVID-19 Global Research on Coronavirus Disease database. We will consider observational studies that report statistical relationships between the SDOHs (as listed in PROGRESS-Plus and Healthy People 2020) and COVID-19 transmission and outcomes. There will be no limitation on the geographical location of publications. The quality of included observational studies will be assessed using a modified version of the Newcastle-Ottawa Scale. A narrative synthesis without meta-analysis reporting standards will be used to report the review findings. ETHICS AND DISSEMINATION: This review will be based on published studies obtained from publicly available sources, and therefore, ethical approval is not required. We will publish the results of this review in a peer-reviewed journal, as well as present the study findings at a national conference. PROSPERO REGISTRATION NUMBER: CRD42021228818.
