Humoral immunological kinetics of severe acute respiratory syndrome coronavirus 2 infection and diagnostic performance of serological assays for coronavirus disease 2019: an analysis of global reports.

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.

Sero-epidemiology of human T-cell lymphotropic viruses-1 and -2 infection among pregnant women attending Abuja Teaching Hospital, Nigeria.

BACKGROUND: There is the paucity of HTLV-1/-2 studies on Nigerian pregnant women despite the medical and public health significance of maternal-to-child transmission of HTLV-1/-2. OBJECTIVE: This study aims to determine the seroprevalence and risk factors of HTLV-1/-2 infections among pregnant women attending the University of Abuja Teaching Hospital (UATH), Abuja, Nigeria. MATERIALS AND METHODS: Blood samples were collected from consented pregnant women and analysed for ant-HTLV-1/-2 total antibodies using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Pretested structured questionnaires were used to collate participants' socio-demographic variables and risk factors of HTLV infection. RESULTS: Out of the 156 pregnant women tested for HTLV-1/-2 antibodies, 16 (10.3%) were seropositive. There was no significant association between the socio-demographic variables collated and seroprevalence of HTLV-1/-2 infection among pregnant women (p> 0.05). Pregnant women with HIV infection had a lower prevalence of HLTV-1/-2 infection than those without HIV infections (7.5% versus 11.7%). Pregnant women with multiple sexual partners had a higher risk of HTLV-1/-2 infection than those who had single (OR = 2.08, 95% CI: 0.53-8.18). Women with a history of needles injury had a higher risk of HTLV-1/-2 infection than those who do not (OR = 1.24, 95% CI: 0.38-4.08). The history of blood transfusion was significantly associated with HTLV-1/-2 infection (p= 0.027). However, no significant association existed between other risk factors of HTLV-1/-2 infection among pregnant women (p> 0.05). CONCLUSION: Considering the 3% pooled national prevalence of HTLV-1/-2 infection in Nigeria, the seroprevalence reported in this study is relatively high. Thus, there is a need for more large cohort studies and routine screening of population at increased risk of infection.

Understanding the implications of SARS-CoV-2 re-infections on immune response milieu, laboratory tests and control measures against COVID-19.

Several months after the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), cases of re-infection after recovery were reported. The extent and duration of protective immunity after SARS-CoV-2 infection is not fully understood. As such, the possibility of re-infection with SARS-CoV-2. Furthermore, cases of re-infection were mainly due to different variants or mutant SARS-CoV-2. Following the fast and pandemic-scale spread of COVID-19, mutations in SARS-CoV-2 have raised new diagnostic challenges which include the redesign of the oligonucleotide sequences used in RT-PCR assays to avoid potential primer-sample mismatches, and decrease sensitivities. Since the initial wave of the pandemic, some regions had experienced fresh outbreaks, predisposing people to be susceptible to SARS-CoV-2 re-infection. Hence, this article sought to offer detailed biology of SARS-CoV-2 re-infections and their implications on immune response milieu, diagnostic laboratory tests and control measures against COVID-19.

Leveraging on the genomics and immunopathology of SARS-CoV-2 for vaccines development: prospects and challenges.

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.