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Introduction: in 2016, a switch from trivalent oral poliovirus vaccine (OPV) (containing serotypes 1,2,3) to bivalent OPV (types 1,3) was implemented globally. We assessed the seroprevalence of poliovirus antibody levels in selected Nigerian states, before and after the switch, documented poliovirus type2 outbreak responses conducted and ascertained factors associated with immunity gaps based on seroprevalence rates., Methods: we conducted a secondary analysis of stored serum samples from the 2018 Nigeria National HIV/AIDS Indicator and Impact Survey. Serum from 1,185 children aged 0-119 months residing in one southern and four northern states were tested for serotype-specific PV neutralizing antibodies; seropositivity was a reciprocal titer ≥8. We conducted regression analysis to determine sociodemographic risk factors associated with low seroprevalence using SAS 9.4., Results: children aged 24-119 months (pre-switch cohort) had seroprevalence against PV1, PV2, and PV3, of 97.3% (95% CI:96.4-98.2), 93.8% (95% CI:92.2-95.5), and 91.3% (95% CI:89.2-93.4), while children aged <24 months (post-switch) had seroprevalence of 86.0% (95% CI:81.2-90.8), 55.6% (95% CI: 47.7-63.4), and 77.2% (95% CI:71.0-83.4) respectively. Regression analysis showed age <24 months was associated with lower seroprevalence against all PV serotypes, (p<0.0001); females had lower seroprevalence against PV1 (p=0.0184) and PV2 (p=0.0354); northern states lower seroprevalence against PV1 (p=0.0039), while well-water source lower seroprevalence against PV3 (p=0.0288)., Conclusion: this study showed high seroprevalence rates against PV 1, 2, and 3 in pre-switch children (aged 24-119 months). However, post-switch children (<24 months) had low immunity against PV2 despite outbreak responses. Strategies to increase routine immunization coverage and high-quality polio campaigns can increase immunity against polio virus., Competing Interests: The authors declare no competing interests., (©Omotayo Bolu et al.)

Yaws is a chronic, relapsing disease of skin, bone, and cartilage caused by Treponema pallidum subsp. pertenue. Yaws was last reported in Nigeria in 1996, although neighboring countries have recently reported cases. We investigated serological evidence for yaws among children aged 0-14 years in Nigeria by measuring antibodies to the treponemal antigens rp17 and TmpA in blood specimens from a 2018 nationally representative HIV survey using a multiplex bead assay. The presence of antibodies to both antigens ("double positive") likely reflects current or recent treponemal infection. Overall, 1.9% (610/31,549) of children had anti-TmpA antibodies, 1.5% (476/31,549) had anti-rp17 antibodies, and 0.1% (39/31,549) were double positive. Among households, 0.5% (84/18,021) had a double-positive child, with a clustering of double-positive children. Although numbers are low, identification of antibodies to both TmpA and rp17 may warrant investigation, including more granular epidemiologic and clinical data, to assess the potential for continuing yaws transmission in Nigerian children.

Accurate SARS-CoV-2 serological assays are critical for COVID-19 serosurveillance. However, previous studies have indicated possible cross-reactivity of these assays, including in areas where malaria is endemic. We tested 213 well-characterized prepandemic samples from Nigeria using two SARS-CoV-2 serological assays, Abbott Architect IgG and Euroimmun NCP IgG assay, both targeting SARS-CoV-2 nucleocapsid protein. To assess antibody binding strength, an avidity assay was performed on these samples and on plasma from SARS-CoV-2 PCR-positive persons. Thirteen (6.1%) of 212 samples run on the Abbott assay and 38 (17.8%) of 213 run on the Euroimmun assay were positive. Anti- Plasmodium IgG levels were significantly higher among false positives for both Abbott and Euroimmun; no association was found with active Plasmodium falciparum infection. An avidity assay using various concentrations of urea wash in the Euroimmun assay reduced loosely bound IgG: of 37 positive/borderline prepandemic samples, 46%, 86%, 89%, and 97% became negative using 2 M, 4 M, 5 M, and 8 M urea washes, respectively. The wash slightly reduced avidity of antibodies from SARS-CoV-2 patients within 28 days of PCR confirmation; thereafter, avidity increased for all urea concentrations except 8 M. This validation found moderate to substantial cross-reactivity on two SARS-CoV-2 serological assays using samples from a setting where malaria is endemic. A simple urea wash appeared to alleviate issues of cross-reactivity.

Background: The Institute of Human Virology Nigeria (IHVN) - Human Heredity and Health in Africa (H3Africa) Biorepository (I-HAB) seeks to provide high-quality biospecimens for research. This depends on the ability of clinical research sites (CRS) - who provide biospecimens - to operate according to well-established industry standards. Yet, standards are often neglected at CRSs located in Africa. Here, I-HAB reports on its four-pronged approach to empower CRSs to prepare high-quality biospecimens for research., Objectives: I-HAB sought (1) to assess a four-pronged approach to improve biobanking practices and sample quality among CRSs, and (2) to build human capacity., Methods: I-HAB partnered with two H3Africa principal investigators located in Nigeria and Ghana from August 2013 through to May 2017 to debut its four-pronged approach (needs assessment, training and mentorship, pilot, and continuous quality improvement) to empower CRSs to attain high-quality biospecimens., Results: Close collaborations were instrumental in establishing mutually beneficial and lasting relationships. Improvements during the 12 months of engagement with CRSs involved personnel, procedural, and supply upgrades. In total, 51 staff were trained in over 20 topics. During the pilot, CRSs extracted 50 DNA biospecimens from whole blood and performed quality control. The CRSs shipped extracted DNA to I-HAB and I-HAB that comparatively analysed the DNA. Remediation was achieved via recommendations, training, and mentorship. Preanalytical, analytical and post-analytical processes, standard operating procedures, and workflows were systematically developed., Conclusion: Partnerships between I-HAB and H3Africa CRSs enabled research sites to produce high-quality biospecimens through needs assessment, training and mentorship, pilot, and continuous monitoring and improvement., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article., (© 2020. The Authors.)

Background: Genetic diversity is abundant on the African continent. However, genomic research has been hampered by a lack of high quality and extensively annotated biospecimens and the necessary infrastructure to support such a technology-intensive effort., Objective: The Institute of Human Virology Nigeria (IHVN) partnered with the H3Africa Consortium and the Coriell Institute for Medical Research to build an internationally recognised biorepository for the receipt, processing, storage and distribution of biospecimens for biomedical research. Here, the authors describe the procedures, challenges and results encountered., Results: Key requirements for a high-quality biorepository were identified: (1) institutional support of infrastructure and services, (2) on-site trained staff with primary commitment to the biorepository, (3) reliance on best practices from globally recognised biorepository groups, (4) early implementation of a quality management system, (5) adoption of a laboratory information management system with demonstrated versatility in functions, (6) collaboration with external experts and sharing of experience through abstracts, newsletters, published manuscripts, and attendance at meetings and workshops, (7) strict adherence to local and national ethical standards and (8) a sustainability plan that is reviewed and updated annually., Conclusion: Utilising published best practices of globally recognised experts in the biorepository field as a benchmark, IHVN expanded and reorganised its existing laboratory facility and staff to take on this new purpose., Competing Interests: The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.