No abstract

As the coronavirus disease 2019 (COVID-19) pandemic continues to rise and second waves are reported in some countries, serological test kits and strips are being considered to scale up an adequate laboratory response. This study provides an update on the kinetics of humoral immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and performance characteristics of serological protocols (lateral flow assay [LFA], chemiluminescence immunoassay [CLIA] and ELISA) used for evaluations of recent and past SARS-CoV-2 infection. A thorough and comprehensive review of suitable and eligible full-text articles was performed on PubMed, Scopus, Web of Science, Wordometer and medRxiv from 10 January to 16 July 2020. These articles were searched using the Medical Subject Headings terms ‘COVID-19’, ‘Serological assay’, ‘Laboratory Diagnosis’, ‘Performance characteristics’, ‘POCT’, ‘LFA’, ‘CLIA’, ‘ELISA’ and ‘SARS-CoV-2’. Data from original research articles on SARS-CoV-2 antibody detection ≥second day postinfection were included in this study. In total, there were 7938 published articles on humoral immune response and laboratory diagnosis of COVID-19. Of these, 74 were included in this study. The detection, peak and decline period of blood anti-SARS-CoV-2 IgM, IgG and total antibodies for point-of-care testing (POCT), ELISA and CLIA vary widely. The most promising of these assays for POCT detected anti-SARS-CoV-2 at day 3 postinfection and peaked on the 15th day; ELISA products detected anti-SARS-CoV-2 IgM and IgG at days 2 and 6 then peaked on the eighth day; and the most promising CLIA product detected anti-SARS-CoV-2 at day 1 and peaked on the 30th day. The most promising LFA, ELISA and CLIA that had the best performance characteristics were those targeting total SARS-CoV-2 antibodies followed by those targeting anti-SARS-CoV-2 IgG then IgM. Essentially, the CLIA-based SARS-CoV-2 tests had the best performance characteristics, followed by ELISA then POCT. Given the varied performance characteristics of all the serological assays, there is a need to continuously improve their detection thresholds, as well as to monitor and re-evaluate their performances to assure their significance and applicability for COVID-19 clinical and epidemiological purposes.

The 2019 and 2020 sporadic outbreaks of Yellow fever (YF) in Sub-Saharan Africa (SSA) countries had raised a lot of global health concerns. This article aims to narratively review the vector biology, YF vaccination program, environmental factors and climatic changes, and to understand how they could facilitate the re-emergence of YF. This study comprehensively reviewed articles that focused on the interplay and complexity of YF Virus (YFV) vector diversity/competence, YF vaccine immunodynamics, and climatic changes impacts on YFV transmission as they influence the 2019/2020 sporadic outbreaks in Sub-Saharan Africa (SSA). Based on available reports, vectorial migration, climatic changes, and YF immunization level could be reasons for the re-emergence of YF at the community and national levels. Essentially, the drivers of YFV infection due to spillover are moderately constant. However, changes in land use and landscape have been shown to influence sylvan-to-urban spillover. Furthermore, increased precipitation and warmer temperatures due to climate change, are likely to broaden the range of mosquitoes' habitat. The 2019/2020 YF outbreaks in SSA is basically a result of inadequate vaccination campaigns, YF surveillance and vector control. Consequently, and most importantly, adequate immunization coverage must be implemented and properly achieved under the responsibility of the public health stakeholders.

The incidence and case-fatality rates (CFRs) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, the etiological agent for Coronavirus Disease 2019 (COVID-19), have been rising unabated. Even though the entire world has been implementing infection prevention and control measures, the pandemic continues to spread. It has been widely accepted that preventive vaccination strategies are the public health measures for countering this pandemic. This study critically reviews the latest scientific advancement in genomics, replication pattern, pathogenesis, and immunopathology of SARS-CoV-2 infection and how these concepts could be used in the development of vaccines. We also offer a detailed discussion on the anticipated potency, efficacy, safety, and pharmaco-economic issues that are and will be associated with candidate COVID-19 vaccines.

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS- has resulted in an unprecedented global health security challenge, economic downturns and psychosocial disruptions. First reported in Wuhan, China, the epidemic swiftly spread to over 200 countries and territories. In Nigeria, the first confirmed COVID-19 case was imported via air travel on 24 th of February 2020 and Confirmed on 27 th of February 2020. Minimal public health surveillance activities were initiated before then. In response to the confirmation of COVID-19, incident management activities, epidemiologic surveillance, contact tracing, infection, prevention and control trainings, COVID-19 testing and activation of isolation and treatment centers were immediately implemented in Ogun State. The objective of the outbreak investigation in Ogun State was to determine the magnitude of the outbreak, characterize the outbreak, and implement disease detection and response activities. This report documents and reflects on the steps taken to mitigate the initial spread of COVID-19 and the outbreak response activities in Ogun State, Nigeria. Adequate risk communication, robust surveillance, effective contact tracing and isolation of primary contacts of the first confirmed case in Nigeria as well as implementation of infection, prevention and control measures were pivotal tools that helped to curtail the initial spread of the infection. Operative collaboration between all stakeholders involved in response and surveillance to emerging dangers is necessary to detect cases early and to implement adequate preventive and control measures.