Objectives: Determining an accurate estimate of SARS-CoV-2 seroprevalence has been challenging in African countries where malaria and other pathogens are endemic. We compared the performance of one single-antigen assay and three multi-antigen SARS-CoV-2 IgG assays in a Nigerian population endemic for malaria. Methods: De-identified plasma specimens from SARS-CoV-2 RT-PCR positive, dried blood spot (DBS) SARS-CoV-2 RT-PCR positive, and pre-pandemic negatives were used to evaluate the performance of the four SARS-CoV-2 assays (Tetracore, SARS2MBA, RightSign, xMAP). Results: Results showed higher sensitivity with the multi-antigen (81% (Tetracore), 96% (SARS2MBA), 85% (xMAP)) versus the single-antigen (RightSign (64%)) SARS-CoV-2 assay. The overall specificities were 98% (Tetracore), 100% (SARS2MBA and RightSign), and 99% (xMAP). When stratified based on <15 days to ≥15 days post-RT-PCR confirmation, the sensitivities increased from 75% to 88.2% for Tetracore; from 93% to 100% for the SARS2MBA; from 58% to 73% for RightSign; and from 83% to 88% for xMAP. With DBS, there was no positive increase after 15-28 days for the three assays (Tetracore, SARS2MBA, and xMAP). Conclusion: Multi-antigen assays performed well in Nigeria, even with samples with known malaria reactivity, and might provide more accurate measures of COVID-19 seroprevalence and vaccine efficacy.

IntroductionHuman Papillomavirus (HPV) infection is a risk factor for cervical cancer, the fourth most common cancer among women globally. Its burden is the highest in sub-Saharan Africa, with over 90% mortality. Interventions may fail without evidence-based data on stratified prevalence and risk factors among most at-risk women across Nigeria.MethodsA cross-sectional comparative study, with participants recruited from the Nigerian Institute of Medical Research’s Clinics, NGO outreaches, a cancer screening centre and a university teaching hospital. Questionnaires were self-administered. Trained medics performed sampling at healthcare facilities, and self-sampling was used at outreaches.ResultsNine hundred eighty-five study participants were recruited. About 37% and 27% of the women knew about HPV and its vaccines, respectively, but only 6% confirmed vaccination with HPV vaccines. HPV prevalence was highest among women with unknown marital status (35.9%), single women (33.8%), widowed/divorced/separated women (30.3%), and married/cohabiting women (19.6%). HPV infection was significantly higher among women who take alcohol (odds=1.7 [95% CI: 1.2-2.4]) and women who smoke (odds=2.6 [95% CI: 1.4 - 4.6]. HPV strains detected included HPV16 (1.3%), HPV18 (1.5%), Low Risk (0.2%) and Other High-Risk groups (19.7%).ConclusionThe inverse relationship between prevalence and education suggests interventions improving awareness and prevention would be impactful. Such interventions could also target HIV-positive women, women presenting with sexually-transmitted infections, who smoke and frequently drink alcohol.

Hepatitis B virus (HBV) infection is an important public health challenge. More than 350,000,000 people worldwide have chronic hepatitis B (CHB). Hepatitis B core ImmunoglobinM(HBc IgM) is an important marker used to classify whether an existing HBV is a new infection or an existing one, differentiating acute from chronic HBV infection. When an individual is HBc IgM positive, it shows a new infection, while negative IgM indicates a previous infection. The study aimed to determine the trend of acute HBV infections among hepatitis B-positive patients in a tertiary health facility in Lagos, Nigeria, over a four-year period. Patients accessing HBc IgM tests at a tertiary health facility in Lagos, Nigeria. Five (5) ml of blood samples were collected in K+EDTA vacutainers and centrifuged at 3500 rpm for 5 minutes. Plasma (2 ml) was collected in plain tubes, and HBc IgM assay was performed using DIA-Pro (BIORAD) kits according to the manufacturer’s instructions. The study period was from January 2014 to December 2017. The total number of patients who accessed this assay within the study period was 1,422. The male population was 896 (61.1%). Total HBc IgM positive and HBc IgM negative results were 197 (13.8%) and 1,225 (86.1%) respectively, and there was 1 (0.07%) equivocal. Rates of HBc IgM positivity, indicating acute infection, were 12.9%, 13.0%, 11.9%, and 15.1% in the years 2014, 2015, 2016, and 2017 respectively. The rate of acute HBV infection increased from 12.9% in 2014 to 15.1% in 2017, indicating likely new infection transmission ongoing in communities. These high and increasing rates require the sustenance of public health interventions.

Abstract Objective To evaluate the feasibility and performance of self-collected vaginal swab samples for HPV screening among women in Lagos, Nigeria. Methods A cross-sectional study was implemented from March to August 2020 among sexually active women. Study participants provided same-day paired vaginal swab samples. Medic-sampling and poster-directed self-sampling methods were used to collect the two samples per participant. A real-time PCR assay detected HPV 16, HPV 18, other-high-risk (OHR) HPV, and the human β-globin gene. The self-collected samples’ sensitivity, specificity, and accuracy were determined against the medic-collected samples using the MedCalc Online Diagnostic Calculator. Results Of the 213 women aged 16 ~ 63-year-old recruited, 187 (88%) participants had concordant results, while 26 (12%) participants had discordant results. Among the 187 concordant results, 35 (19%) were HPV positive, 150 (80%) participants were HPV negative, and two (1%) were invalid. 18 (69%) out of the 26 discordant samples were invalid. The self-collected sample was invalid for 14 (54%) participants. Two (8%) medic-collected samples were invalid. Compared to the medic-collected sample, the self-collected sample was 89.80% (95% CI: 77.77 ~ 96.60%) sensitive and 98.21% (95% CI: 94.87 ~ 99.63%) specific, with an accuracy of 96.31% (95% CI: 92.87 ~ 98.40%). The mean age for HPV positive and negative participants were 39 and 40, respectively, with an ANOVA p-value of 0.3932. The stratification of HPV infection by the age group was not statistically significant (P > 0.05). Conclusions With high accuracy of 96%, self-collected sampling is adequate when tested with real-time PCR and may increase the uptake of HPV testing. Though more self-collected samples were invalid than medic-collected samples, most likely due to poor collection, they could be identified for repeat testing. Future implementation can avoid this error with improved guidance and awareness.

ObjectiveThere is a need for reliable serological assays to determine accurate estimates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence. Most single target antigen assays have shown some limitations in Africa. To assess the performance of a multi-antigen assay, we evaluated a commercially available SARS-CoV-2 Multi-Antigen IgG assay for human coronavirus disease 2019 (COVID-19) in Nigeria. MethodsValidation of the xMAP SARS-CoV-2 Multi-Antigen IgG assay was carried out using well-characterized SARS-CoV-2 reverse transcription polymerase chain reactive positive (97) and pre-COVID-19 pandemic (86) plasma panels. Cross-reactivity was assessed using pre-COVID-19 pandemic plasma specimens (213) from the 2018 Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS). ResultsThe overall sensitivity of the xMAP SARS-CoV-2 Multi-Antigen IgG assay was 75.3% [95% CI: 65.8%- 82.8%] and specificity was 99.0% [95% CI: 96.8%- 99.7%]. The sensitivity estimate increased to 83.3% [95% CI: 70.4%- 91.3%] for specimens >14 days post-confirmation of diagnosis. However, using the NAIIS pre-pandemic specimens, the false positivity rate was 1.4% (3/213). ConclusionsOur results showed overall lower sensitivity and a comparable specificity with the manufacturer's validation. There appears to be less cross-reactivity with NAIIS pre-pandemic COVID-19 specimens using the xMAP SARS-CoV-2 Multi-Antigen IgG assay. In-country SARS-CoV-2 serology assay validation can help guide the best choice of assays in Africa.

COVID‐19 pandemic has posed unique challenges to the health providers involved with chronic diseases like Haemoglobin disorders (sickle cell disease). Therefore, this study highlights the susceptibility and severity of COVID‐19 associated with normal and haemoglobin variants. This study is a case series that includes patients evaluated between June and August 30, 2020, and diagnosed with COVID-19 by the Quantitative Polymerase Chain Reaction method. Alkaline haemoglobin electrophoresis was used to identify types of Haemoglobin genotype associated with mild-to-severe cases of COVID-19. A total of 697 COVID-19 patients were included in this study, with a mean age of 41.32 (12.917). There were more males (66.1%) than females. The most frequently detected genotype was AA (75.8%), followed by AS (22%). Severe conditions of COVID-19 were present in patients with HBAC 2(14.28%) and HBAS 13 (8.5%). Co-morbidities were present in (24.0%) of the patients, with a mortality rate of 1.3%. Patients with pneumonia in association with other co-morbidities are 26 times more likely to have severe SARS CoV-2 than those with only pneumonia, irrespective of their haemoglobin genotype profile. The clinical course is seen in normal haemoglobin, and the variant with COVID-19 was the same. It is suggested that people with haemoglobin variant are not at increased risk during COVID-19 infection or risk of a sickle cell crisis.

Background and Aims: Diarrheal diseases caused by bacterial pathogens are widespread and they result in morbidity and mortality of a lot of people yearly. The aim of this study was to assess the role of the environment, health workers and food handlers as reservoirs of Vibrio cholerae, and other diarrhea causing bacteria. Methods: Healthcare workers were proportionally selected and multistage sampling technique was adopted in selecting food handlers for the study. A total of 374 participants consisting of health workers and food handlers were recruited. Socio-demographic and clinical information were collected using questionnaires, while stool and environmental samples were also collected. Results: More female 55.9 % than male 44.1 % participated in the study and the mean age of participants was 38.7 ± 10.9. A significant number of participants identified poor hygiene practices as the major cause of diarrhea. V. cholerae O1 serotype was not detected in any of the environmental samples nor stool samples of both food handlers and health workers. However, V. cholerae (Non O1/Non O139) was isolated from the stool samples of food handlers and health workers in Kano State implying that they could be serving a source of the continuous dissemination of the pathogen. Other bacterial pathogens that are aetiology of diarrhea including Salmonella spp. Escherichia coli, Klebsiella oxytoca, and Enterobacter spp. were also isolated. Conclusion: It is therefore imperative that food handlers and health workers undergo periodic health checks to ensure they are free of pathogens they could easily transmit through food or to patients.

Validated assays are essential for reliable serosurveys; however, most SARS-CoV-2 immunoassays have been validated using specimens from China, Europe, or U.S. populations. We evaluated the performance of five commercial SARS-CoV-2 immunoassays to inform their use in serosurveys in Nigeria. Four semiquantitative enzyme-linked immunosorbent assays (ELISAs) (Euroimmun anti-SARS-CoV-2 nucleocapsid protein [NCP] immunoglobulin G [IgG], Euroimmun spike SARS-CoV-2 IgG, Mologic Omega COVID-19 IgG, Bio-Rad Platelia SARS-CoV-2 Total Ab) and one chemiluminescent microparticle immunoassay (Abbott Architect SARS-CoV-2 IgG) were evaluated. We estimated the analytical performance characteristics using plasma from 100 SARS-CoV-2 PCR-positive patients from varied time points post-PCR confirmation and 100 prepandemic samples (50 HIV positive and 50 hepatitis B positive). The Bio-Rad assay failed the manufacturer-specified validation steps. The Euroimmun NCP, Euroimmun spike, and Mologic assays had sensitivities of 73.7%, 74.4%, and 76.9%, respectively, on samples taken 15 to 58 days after PCR confirmation and specificities of 97%, 100%, and 83.8%, respectively. The Abbott assay had 71.3% sensitivity and 100% specificity on the same panel. Parallel or serial algorithms combining two tests did not substantially improve the sensitivity or specificity. Our results showed lower sensitivity and, for one immunoassay, lower specificity compared to the manufacturers' results and other reported validations. Seroprevalence estimates using these assays might need to be interpreted with caution in Nigeria and similar settings. These findings highlight the importance of in-country validations of SARS-CoV-2 serological assays prior to use to ensure that accurate results are available for public health decision-making to control the COVID-19 pandemic in Africa. IMPORTANCE This study used positive and negative sample panels from Nigeria to test the performance of several commercially available SARS-CoV-2 serological assays. Using these prepandemic and SARS-CoV-2-positive samples, we found much lower levels of sensitivity in four commercially available assays than most assay manufacturer reports and independent evaluations. The use of these assays with suboptimal sensitivity and specificity in Nigeria or countries with population exposure to similar endemic pathogens could lead to a biased estimate of the seroprevalence, over- or underestimating the true disease prevalence, and limit efforts to stop the spread of SARS-CoV-2. It is important to conduct in-country validations of serological SARS-CoV-2 assays prior to their widespread use, especially in countries with limited representation in published assay validations.

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.

INTRODUCTION:COVID-19 is an emerging, rapidly evolving global situation, infecting over 25 million people and causing more than 850,000 deaths. Several signs and symptoms have been described to be characteristic of the disease. However, there is a dearth of report on the description of the clinical characteristics of the disease in patients from Nigeria. This study was designed to provide a description of the clinical and demographic characteristics of COVID-19 patients in Nigeria.METHODS:This study is a case series that includes patients that are evaluated between May and August 2020, and diagnosed with COVID-19. Patient health records were reviewed and evaluated to describe the clinical characteristics on presentation.RESULTS:A total of 154 COVID-19 patients were included in this study, with a mean age (S.D.) of 46.16 (13.701). Most of the patients survived (mortality rate of 2.6%), and were symptomatic (89.6%). There were more males (74.7%) than females, and the most common symptoms were fever, breathing difficulty, dry cough and malaise. Co-morbidities were also present in almost half of the study participants (49.4%).CONCLUSION:This study presents the most extensive description, to date, on the clinical and demographic characteristics of COVID-19 patients in Nigeria. Males are more likely than females to be infected with COVID-19 and the most occurring symptoms are fever, breathing difficulty, malaise, dry cough and chest pain. Old age and the presence of co-morbidities may also be associated with developing the severe disease.