Factors associated with delayed presentation to healthcare facilities for Lassa fever cases, Nigeria 2019: a retrospective cohort study.

BACKGROUND: Large outbreaks of Lassa fever (LF) occur annually in Nigeria. The case fatality rate among hospitalised cases is ~ 20%. The antiviral drug ribavirin along with supportive care and rehydration are the recommended treatments but must be administered early (within 6 days of symptom onset) for optimal results. We aimed to identify factors associated with late presentation of LF cases to a healthcare facility to inform interventions. METHODS: We undertook a retrospective cohort study of all laboratory confirmed LF cases reported in Nigeria from December 2018 to April 2019. We performed descriptive epidemiology and a univariate Cox proportional-hazards regression analysis to investigate the effect of clinical (symptom severity), epidemiological (age, sex, education, occupation, residential State) and exposure (travel, attendance at funeral, exposure to rodents or confirmed case) factors on time to presentation. RESULTS: Of 389 cases, median presentation time was 6 days (IQR 4-10 days), with 53% attending within 6 days. There were no differences in presentation times by sex but differences were noted by age-group; 60+ year-olds had the longest delays while 13-17 year-olds had the shortest. By sex and age, there were differences seen among the younger ages, with 0-4-year-old females presenting earlier than males (4 days and 73% vs. 10 days and 30%). For 5-12 and 13-17 year-olds, males presented sooner than females (males: 5 days, 65% and 3 days, 85% vs. females: 6 days, 50% and 5 days, 61%, respectively). Presentation times differed across occupations 4.5-9 days and 20-60%, transporters (people who drive informal public transport vehicles) had the longest delays. Other data were limited (41-95% missing). However, the Cox regression showed no factors were statistically associated with longer presentation time. CONCLUSIONS: Whilst we observed important differences in presentation delays across factors, our sample size was insufficient to show any statistically significant differences that might exist. However, almost half of cases presented after 6 days of onset, highlighting the need for more accurate and complete surveillance data to determine if there is a systemic or specific cause for delays, so to inform, monitor and evaluate public health strategies and improve outcomes.

Epidemiologic and Clinical Features of Lassa Fever Outbreak in Nigeria, January 1-May 6, 2018.

Lassa fever (LF) is endemic to Nigeria, where the disease causes substantial rates of illness and death. In this article, we report an analysis of the epidemiologic and clinical aspects of the LF outbreak that occurred in Nigeria during January 1-May 6, 2018. A total of 1,893 cases were reported; 423 were laboratory-confirmed cases, among which 106 deaths were recorded (case-fatality rate 25.1%). Among all confirmed cases, 37 occurred in healthcare workers. The secondary attack rate among 5,001 contacts was 0.56%. Most (80.6%) confirmed cases were reported from 3 states (Edo, Ondo, and Ebonyi). Fatal outcomes were significantly associated with being elderly; no administration of ribavirin; and the presence of a cough, hemorrhaging, and unconsciousness. The findings in this study should lead to further LF research and provide guidance to those preparing to respond to future outbreaks.

Increase in Lassa Fever Cases in Nigeria, January-March 2018.

We reviewed data pertaining to the massive wave of Lassa fever cases that occurred in Nigeria in 2018. No new virus strains were detected, but in 2018, the outbreak response was intensified, additional diagnostic support was available, and surveillance sensitivity increased. These factors probably contributed to the high case count.

A cholera outbreak in a rural north central Nigerian community: an unmatched case-control study.

BACKGROUND: Cholera remains a disease of public health importance in Nigeria associated with high morbidity and mortality. In November 2014, the Nigeria Field Epidemiology and Laboratory Training Programme (NFELTP) was notified of an increase in suspected cholera cases in Gomani, Kwali Local Government Area. NFELTP residents were deployed to investigate the outbreak with the objectives of verifying the diagnosis, identifying risk factors and instituting appropriate control measures to control the outbreak. METHODS: We conducted an unmatched case-control study. We defined a cholera case as any person aged ≥5 years with acute watery diarrhea in Gomani community. We identified community controls. A total of 43 cases and 68 controls were recruited. Structured questionnaires were administered to both cases and controls. Four stool samples from case-patients and two water samples from the community water source were collected for laboratory investigation. We performed univariate and bivariate analysis using Epi-Info version 7.1.3.10. RESULTS: The mean age of cases and controls was 20.3 years and 25.4 respectively (p value 0.09). Females constituted 58.1% (cases) and 51.5%(controls). The attack rate was 4.3% with a case fatality rate of 13%. Four stool (100%) specimen tested positive for Vibrio cholerae. The water source and environment were polluted by indiscriminate defecation. Compared to controls, cases were more likely to have drank from Zamani river (OR 14.2, 95% CI: 5.5-36.8) and living in households(HH) with more than 5 persons/HH (OR 5.9, 95% CI: 1.3-27.2). Good hand hygiene was found to be protective (OR 0.3, 95% CI: 0.1-0.7). CONCLUSION: Vibrio cholerae was the cause of the outbreak in Gomani. Drinking water from Zamani river, living in overcrowded HH and poor hand hygiene were significantly associated with the outbreak. We initiated hand hygiene and water treatment to control the outbreak.

Measures to control protracted large Lassa fever outbreak in Nigeria, 1 January to 28 April 2019.

Lassa fever cases have increased in Nigeria since 2016 with the highest number, 633 cases, reported in 2018. From 1 January to 28 April 2019, 554 laboratory-confirmed cases including 124 deaths were reported in 21 states in Nigeria. A public health emergency was declared on 22 January by the Nigeria Centre for Disease Control. We describe the various outbreak responses that have been implemented, including establishment of emergency thresholds and guidelines for case management.

Field evaluation of validity and feasibility of Pan-Lassa rapid diagnostic test for Lassa fever in Abakaliki, Nigeria: a prospective diagnostic accuracy study.

BACKGROUND: Lassa fever is a viral haemorrhagic fever with few options for diagnosis and treatment; it is also under-researched with knowledge gaps on its epidemiology. A point-of-care bedside test diagnosing Lassa fever, adhering to REASSURED criteria, is not currently available but is urgently needed in west African regions with high Lassa fever burden. We aimed to assess the validity and feasibility of a rapid diagnostic test (RDT) to confirm Lassa fever in people in Nigeria. METHODS: We estimated the diagnostic performance of the ReLASV Pan-Lassa RDT (Zalgen Labs, Frederick, MD, USA) as a research-use-only test, compared to RT-PCR as a reference standard, in 217 participants at a federal tertiary hospital in Abakaliki, Nigeria. We recruited participants between Feb 17, 2022, and April 17, 2023. The RDT was performed using capillary blood at the patient bedside and using plasma at the laboratory. The performance of the test, based on REASSURED criteria, was assessed for user friendliness, rapidity and robustness, sensitivity, and specificity. FINDINGS: Participants were aged between 0 and 85 years, with a median age of 33·0 years (IQR 22·0-44·3), and 24 participants were younger than 18 years. 107 (50%) participants were women and 109 (50%) were men; one participant had missing sex data. Although the specificity of the Pan-Lassa RDT was high (>90%), sensitivity at bedside using capillary blood was estimated as 4% (95% CI 1-14) at 15 min and 10% (3-22) at 25 min, far below the target of 90%. The laboratory-based RDT using plasma showed better sensitivity (46% [32-61] at 15 min and 50% [36-64] at 25 min) but did not reach the target sensitivity. Among the 52 PCR-positive participants with Lassa fever, positive RDT results were associated with lower cycle threshold values (glycoprotein precursor [GPC] gene mean 30·3 [SD 4·3], Large [L] gene mean 32·3 [3·7] vs GPC gene mean 24·5 [3·9], L gene mean 28·0 [3·6]). Personnel conducting the bedside test procedure reported being hindered by the inconvenient use of full personal protective equipment and long waiting procedures before a result could be read. INTERPRETATION: The Pan-Lassa RDT is not currently recommended as a diagnostic or screening tool for suspected Lassa fever cases. Marked improvement in sensitivity and user friendliness is needed for the RDT to be adopted clinically. There remains an urgent need for better Lassa fever diagnostics to promote safety of in-hospital care and better disease outcomes in low-resource settings. FUNDING: Médecins Sans Frontières.

Predictors of Lassa fever diagnosis in suspected cases reporting to health facilities in Nigeria.

Lassa fever (LF) remains endemic in Nigeria with the country reporting the highest incidence and mortality globally. Recent national data suggests increasing incidence and expanding geographic spread. Predictors of LF case positivity in Nigeria have been sparsely studied. We thus sought to determine the sociodemographic and clinical determinants of LF positivity amongst suspected cases presenting to health facilities from 2018 to 2021. A secondary analysis of the national LF surveillance data between January 2018 and December 2021. Socio-demographic and clinical data of 20,027 suspected LF cases were analysed using frequencies and Chi-square statistics with significant p-value set at p < 0.05. The outcome variable was LF case status (positive or negative). Predictors of LF case positivity were assessed using multiple logistic regression models with 95% confidence intervals (CI). Case positivity rate (CPR) for the four years was 15.8% with higher odds of positivity among age group 40-49 years (aOR = 1.40; 95% CI 1.21-1.62), males (aOR = 1.11; 95% CI 1.03-1.20), those with formal education (aOR = 1.33; 95% CI 1.13-1.56), artisans (aOR = 1.70; 95% CI 1.28-2.27), religious leaders (aOR = 1.62; 95% CI 1.04-2.52), farmers (aOR = 1.48; 95% CI 1.21-1.81), and symptomatic individuals (aOR = 2.36; 95% CI 2.09-2.68). Being a health worker (aOR = 0.69; 95% CI 0.53-0.91), a teacher (aOR = 0.69; 95% CI 0.53-0.89) and cases reporting in the 3rd quarter (aOR = 0.79; 95% CI 0.69-0.92) had lower odds. In a sex-disaggregated analysis, female farmers had higher odds of positivity (aOR = 2.43; 95% CI 1.76-3.38; p < 0.001) than male farmers (aOR = 1.52; 95% CI 1.19-1.96; p < 0.01). Fever (aOR = 2.39; 95% CI 2.00-2.84) and gastrointestinal (GI) symptoms (aOR = 2.15; 95% CI 1.94-2.37) had the highest odds among symptoms. Combination of fever and GI symptoms (aOR = 2.15; 95% CI 1.50-3.10), fever and neurological symptoms (aOR = 6.37; 95% CI 1.49-27.16), fever and musculo-skeletal symptoms (aOR = 2.95; 95% CI 1.37-6.33), fever and cardiopulmonary symptoms (aOR = 1.81; 95% CI 1.24-2.64), and cardiopulmonary and general symptoms (aOR = 1.50; 95% CI 1.19-1.89) were also predictive. Cumulative LF CPR appears high with clearly identified predictors. Targeted interventions with heightened index of suspicion for sociodemographic categories predictive of LF in suspected cases are recommended. Ethnographic and further epidemiological studies could aid better understanding of these associations.

A prospective, multi-site, cohort study to estimate incidence of infection and disease due to Lassa fever virus in West African countries (the Enable Lassa research programme)-Study protocol.

BACKGROUND: Lassa fever (LF), a haemorrhagic illness caused by the Lassa fever virus (LASV), is endemic in West Africa and causes 5000 fatalities every year. The true prevalence and incidence rates of LF are unknown as infections are often asymptomatic, clinical presentations are varied, and surveillance systems are not robust. The aim of the Enable Lassa research programme is to estimate the incidences of LASV infection and LF disease in five West African countries. The core protocol described here harmonises key study components, such as eligibility criteria, case definitions, outcome measures, and laboratory tests, which will maximise the comparability of data for between-country analyses. METHOD: We are conducting a prospective cohort study in Benin, Guinea, Liberia, Nigeria (three sites), and Sierra Leone from 2020 to 2023, with 24 months of follow-up. Each site will assess the incidence of LASV infection, LF disease, or both. When both incidences are assessed the LASV cohort (nmin = 1000 per site) will be drawn from the LF cohort (nmin = 5000 per site). During recruitment participants will complete questionnaires on household composition, socioeconomic status, demographic characteristics, and LF history, and blood samples will be collected to determine IgG LASV serostatus. LF disease cohort participants will be contacted biweekly to identify acute febrile cases, from whom blood samples will be drawn to test for active LASV infection using RT-PCR. Symptom and treatment data will be abstracted from medical records of LF cases. LF survivors will be followed up after four months to assess sequelae, specifically sensorineural hearing loss. LASV infection cohort participants will be asked for a blood sample every six months to assess LASV serostatus (IgG and IgM). DISCUSSION: Data on LASV infection and LF disease incidence in West Africa from this research programme will determine the feasibility of future Phase IIb or III clinical trials for LF vaccine candidates.

Adapting public health response through lessons learnt: Nigeria's experience from Lassa fever and COVID-19.

Response to public health emergencies requires continued adaptation and innovation. The Nigeria Centre for Disease Control (NCDC) is the country's public health institute with the mandate to protect the health of Nigerians. Achieving such mandate in resource-limited settings with divergent demographic characteristics of the citizens, necessitates the readiness to learn from experience and to develop policies and activities in line with lessons learnt and best practices. This practice paper describes the initiatives of the NCDC towards adapting its public health response activities by establishing learning systems across its structure. The paper informs on some of the steps taken by the Centre regarding learning from the Lassa fever outbreak and the COVID-19 pandemic in Nigeria. It concludes that commitment and investments are key requirements for learning and adapting public health responses to achieve success with combating infectious diseases.

Epidemiological trends of Lassa fever in Nigeria, 2018-2021.

BACKGROUND: Lassa fever is a viral haemorrhagic fever endemic in Nigeria. Improved surveillance and testing capacity have revealed in an increased number of reported cases and apparent geographic spread of Lassa fever in Nigeria. We described the recent four-year trend of Lassa fever in Nigeria to improve understanding of its epidemiology and inform the design of appropriate interventions. METHODS: We analysed the national surveillance data on Lassa fever maintained by the Nigeria Centre for Diseases Control (NCDC) and described trends, sociodemographic, geographic distribution, and clinical outcomes. We compared cases, positivity, and clinical outcomes in the period January 2018 to December 2021. RESULTS: We found Lassa fever to be reported throughout the year with more than half the cases reported within the first quarter of the year, a recent increase in numbers and geographic spread of the virus, and male and adult (>18 years) preponderance. Case fatality rates were worse in males, the under-five and elderly, during off-peak periods, and among low reporting states. CONCLUSION: Lassa fever is endemic in Nigeria with a recent increase in numbers and geographical distribution. Sustaining improved surveillance, enhanced laboratory diagnosis and improved case management capacity during off-peak periods should remain a priority. Attention should be paid to the very young and elderly during outbreaks. Further research efforts should identify and address specific factors that determine poor clinical outcomes.

Analysis of sociodemographic and clinical factors associated with Lassa fever disease and mortality in Nigeria.

Over past decades, there has been increasing geographical spread of Lassa fever (LF) cases across Nigeria and other countries in West Africa. This increase has been associated with significant morbidity and mortality despite increasing focus on the disease by both local and international scientists. Many of these studies on LF have been limited to few specialised centres in the country. This study was done to identify sociodemographic and clinical predictors of LF disease and related deaths across Nigeria. We analysed retrospective surveillance data on suspected LF cases collected during January-June 2018 and 2019. Multivariable logistic regression analyses were used to identify the factors independently associated with laboratory-confirmed LF diagnosis, and with LF-related deaths. There were confirmed 815 of 1991 suspected LF cases with complete records during this period. Of these, 724/815 confirmed cases had known clinical outcomes, of whom 100 died. LF confirmation was associated with presentation of gastrointestinal tract (aOR 3.47, 95% CI: 2.79-4.32), ear, nose and throat (aOR 2.73, 95% CI: 1.80-4.15), general systemic (aOR 2.12, 95% CI: 1.65-2.70) and chest/respiratory (aOR 1.71, 95% CI: 1.28-2.29) symptoms. Other factors were being male (aOR 1.32, 95% CI: 1.06-1.63), doing business/trading (aOR 2.16, 95% CI: 1.47-3.16) and farming (aOR 1.73, 95% CI: 1.12-2.68). Factors associated with LF mortality were a one-year increase in age (aOR 1.03, 95% CI: 1.01-1.04), bleeding (aOR 2.07, 95% CI: 1.07-4.00), and central nervous manifestations (aOR 5.02, 95% CI: 3.12-10.16). Diverse factors were associated with both LF disease and related death. A closer look at patterns of clinical variables would be helpful to support early detection and management of cases. The findings would also be useful for planning preparedness and response interventions against LF in the country and region.

A standardised Phase III clinical trial framework to assess therapeutic interventions for Lassa fever.

BACKGROUND: Only one recommendation currently exists for the treatment of Lassa fever (LF), which is ribavirin administered in conjunction with supportive care. This recommendation is primarily based on evidence generated from a single clinical trial that was conducted more than 30 years ago-the methodology and results of which have recently come under scrutiny. The requirement for novel therapeutics and reassessment of ribavirin is therefore urgent. However, a significant amount of work now needs to be undertaken to ensure that future trials for LF can be conducted consistently and reliably to facilitate the efficient generation of evidence. METHODOLOGY: We convened a consultation group to establish the position of clinicians and researchers on the core components of future trials. A Core Eligibility Criteria (CEC), Core Case Definition (CCD), Core Outcome Set (COS) and Core Data Variables (CDV) were developed through the process of a multi-stakeholder consultation that took place using a modified-Delphi methodology. RESULTS: A consensus position was achieved for each aspect of the framework, which accounts for the inclusion of pregnant women and children in future LF clinical trials. The framework consists of 8 core criteria, as well as additional considerations for trial protocols. CONCLUSIONS: This project represents the first step towards delineating the clinical development pathway for new Lassa fever therapeutics, following a period of 40 years without advancement. Future planned projects will bolster the work initiated here to continue the advancement of LF clinical research through a regionally-centred, collaborative methodology, with the aim of delineating a clear pathway through which LF clinical trials can progress efficiently and ensure sustainable investments are made in research capacity at a regional level.

COVID-19 mortality rate and its associated factors during the first and second waves in Nigeria.

COVID-19 mortality rate has not been formally assessed in Nigeria. Thus, we aimed to address this gap and identify associated mortality risk factors during the first and second waves in Nigeria. This was a retrospective analysis of national surveillance data from all 37 States in Nigeria between February 27, 2020, and April 3, 2021. The outcome variable was mortality amongst persons who tested positive for SARS-CoV-2 by Reverse-Transcriptase Polymerase Chain Reaction. Incidence rates of COVID-19 mortality was calculated by dividing the number of deaths by total person-time (in days) contributed by the entire study population and presented per 100,000 person-days with 95% Confidence Intervals (95% CI). Adjusted negative binomial regression was used to identify factors associated with COVID-19 mortality. Findings are presented as adjusted Incidence Rate Ratios (aIRR) with 95% CI. The first wave included 65,790 COVID-19 patients, of whom 994 (1∙51%) died; the second wave included 91,089 patients, of whom 513 (0∙56%) died. The incidence rate of COVID-19 mortality was higher in the first wave [54∙25 (95% CI: 50∙98-57∙73)] than in the second wave [19∙19 (17∙60-20∙93)]. Factors independently associated with increased risk of COVID-19 mortality in both waves were: age ≥45 years, male gender [first wave aIRR 1∙65 (1∙35-2∙02) and second wave 1∙52 (1∙11-2∙06)], being symptomatic [aIRR 3∙17 (2∙59-3∙89) and 3∙04 (2∙20-4∙21)], and being hospitalised [aIRR 4∙19 (3∙26-5∙39) and 7∙84 (4∙90-12∙54)]. Relative to South-West, residency in the South-South and North-West was associated with an increased risk of COVID-19 mortality in both waves. In conclusion, the rate of COVID-19 mortality in Nigeria was higher in the first wave than in the second wave, suggesting an improvement in public health response and clinical care in the second wave. However, this needs to be interpreted with caution given the inherent limitations of the country's surveillance system during the study.

Evaluation of infection prevention and control practices in Lassa fever treatment centers in north-central Nigeria during an ongoing Lassa fever outbreak.

BACKGROUND: Outbreaks of Lassa fever (LF) in Nigeria have become more frequent, with increasing more healthcare worker infections. Prevention of infection is dependent on strict compliance to infection prevention and control (IPC) practices in treatment centres where patients are managed. OBJECTIVE: To evaluate IPC practices during an ongoing LF outbreak in the two major tertiary hospitals serving as the referral LF treatment centres in the north-central region of Nigeria. METHODS: This cross-sectional survey was carried out by the IPC subteam of the National Rapid Response Team of the Nigeria Centre for Disease Control (NCDC) deployed to Plateau State, north-central Nigeria during the 2019 LF outbreak. Information on IPC in these facilities was collected using the NCDC viral haemorrhagic fevers (VHFs) isolation and treatment facility IPC survey tool. RESULTS: Both treatment centres had national VHF IPC isolation guidelines and few health workers had received IPC training. In both centres, there were no clearly demarcated entry points for staff going into clinical areas after putting on personal protective equipment, and there were also no standard operating procedures in place for reporting occupational exposure of staff to infected blood or body fluids in both centres. DISCUSSION: The LF treatment centers located in Plateau State during the 2019 LF outbreak were not fully implementing the national VHF IPC guidelines. Periodic assessments of IPC are recommended for proper management of cases and effective control of LF in the State.

Serological markers and risk factors associated with Hepatitis B virus infection among Federal Capital Territory prison inmates, Nigeria: Should we be concerned?

INTRODUCTION: Hepatitis B virus (HBV) infection is hyper-endemic in Nigeria. Prisons are high-risk environments for the spread of infectious diseases. Worldwide, seroprevalence of HBV infection is substantially higher among individuals in correctional facilities when compared to general population. We determined the seroprevalence and risk factors associated with HBV infection among Kuje prison inmates, Nigeria. MATERIAL AND METHODS: We conducted a prison facility based cross-sectional study. Interviewer administered questionnaires were used to obtain information on participants socio-demographic characteristics, HBV risk factors, previous HBV test and vaccination history. Blood samples collected from participants were analysed for HBsAg, HBsAb, HBcAb, HBeAg and HBeAb markers using rapid lateral chromatographic immunoassay kit. Univariate, bivariate, and multivariate analysis were performed. RESULTS: A total of 271 inmates (63 convicts and 208 awaiting trial inmates) were recruited into the study as participants. The mean age of the participants was 32.7 SD±9 years. HBV seroprevalence (HBsAg) of 13.7% (95% CI: 9.8-18.3) was found. 55.4% (95% CI: 49.2-61.4) of inmates were susceptible to HBV infection, 20.7% (95%CI; 16.0-26.0) had past HBV infection while 10.3% (95% CI: 7.0-14.6) had acquired natural or artificial HBV immunity. Factors found to be associated with current HBV infection (HBsAg) include age-group ≤25years (aOR = 8.0,95% CI: 2.9-22.3), being ever married (aOR = 4.2, 95% CI: 1.7-10.4) and history of alcohol consumption (aOR = 3.4, 95% CI: 1.3-8.4). CONCLUSION: This study reveals a high seroprevalence of HBV infection among Kuje Prison inmates, hence the need to introduce prison-focused health intervention initiatives such as HBV screening, vaccination and care to reduce the transmission of HBV infection among inmates and ultimately the general population.

Geographical drivers and climate-linked dynamics of Lassa fever in Nigeria.

Lassa fever is a longstanding public health concern in West Africa. Recent molecular studies have confirmed the fundamental role of the rodent host (Mastomys natalensis) in driving human infections, but control and prevention efforts remain hampered by a limited baseline understanding of the disease's true incidence, geographical distribution and underlying drivers. Here, we show that Lassa fever occurrence and incidence is influenced by climate, poverty, agriculture and urbanisation factors. However, heterogeneous reporting processes and diagnostic laboratory access also appear to be important drivers of the patchy distribution of observed disease incidence. Using spatiotemporal predictive models we show that including climatic variability added retrospective predictive value over a baseline model (11% decrease in out-of-sample predictive error). However, predictions for 2020 show that a climate-driven model performs similarly overall to the baseline model. Overall, with ongoing improvements in surveillance there may be potential for forecasting Lassa fever incidence to inform health planning.

Assessing the capacity of symptom scores to predict COVID-19 positivity in Nigeria: a national derivation and validation cohort study.

OBJECTIVES: This study aimed to develop and validate a symptom prediction tool for COVID-19 test positivity in Nigeria. DESIGN: Predictive modelling study. SETTING: All Nigeria States and the Federal Capital Territory. PARTICIPANTS: A cohort of 43 221 individuals within the national COVID-19 surveillance dataset from 27 February to 27 August 2020. Complete dataset was randomly split into two equal halves: derivation and validation datasets. Using the derivation dataset (n=21 477), backward multivariable logistic regression approach was used to identify symptoms positively associated with COVID-19 positivity (by real-time PCR) in children (≤17 years), adults (18-64 years) and elderly (≥65 years) patients separately. OUTCOME MEASURES: Weighted statistical and clinical scores based on beta regression coefficients and clinicians' judgements, respectively. Using the validation dataset (n=21 744), area under the receiver operating characteristic curve (AUROC) values were used to assess the predictive capacity of individual symptoms, unweighted score and the two weighted scores. RESULTS: Overall, 27.6% of children (4415/15 988), 34.6% of adults (9154/26 441) and 40.0% of elderly (317/792) that had been tested were positive for COVID-19. Best individual symptom predictor of COVID-19 positivity was loss of smell in children (AUROC 0.56, 95% CI 0.55 to 0.56), either fever or cough in adults (AUROC 0.57, 95% CI 0.56 to 0.58) and difficulty in breathing in the elderly (AUROC 0.53, 95% CI 0.48 to 0.58) patients. In children, adults and the elderly patients, all scoring approaches showed similar predictive performance. CONCLUSIONS: The predictive capacity of various symptom scores for COVID-19 positivity was poor overall. However, the findings could serve as an advocacy tool for more investments in resources for capacity strengthening of molecular testing for COVID-19 in Nigeria.

Descriptive epidemiology of Lassa fever in Nigeria, 2012-2017.

INTRODUCTION: Lassa fever, an acute viral hemorrhagic zoonotic disease is endemic in some parts of Nigeria. The disease alert and outbreak threshold are known; however, there has been a shift from the previous seasonal transmission pattern to an all year-round transmission. We described data on Lassa fever and highlighted the magnitude of the disease over a six-year period. METHODS: we conducted a secondary data analyses of Lassa fever specific surveillance data from the Integrated Disease Surveillance and Response (IDSR) records of all states in Nigeria over a six-year period (2012-2017). RESULTS: a total of 5974 suspected cases were reported within the study period; of these, 759 (12.7%) were confirmed by laboratory diagnosis. Highest number of cases was recorded in 2012. Edo and Ondo states in the southern region of the country were mostly affected within the study period. The seasonal trend of Lassa fever cases showed peaks within January to March, except for year 2015. CONCLUSION: there was a high burden of Lassa fever in Nigeria especially in the southern part. Lassa fever transmission occurs all year-round with peaks in January and March. There is need to develop preparedness plans and define thresholds for Lassa fever epidemic.

Improving Cross-Border Preparedness and Response: Lessons Learned from 3 Lassa Fever Outbreaks Across Benin, Nigeria, and Togo, 2017-2019.

Long-standing cultural, economic, and political relationships among Benin, Nigeria, and Togo contribute to the complexity of their cross-border connectivity. The associated human movement increases the risk of international spread of communicable disease. The Benin and Togo ministries of health and the Nigeria Centre for Disease Control, in collaboration with the Abidjan Lagos Corridor Organization (a 5-country intergovernmental organization) and the US Centers for Disease Control and Prevention, sought to minimize the risk of cross-border outbreaks by defining and implementing procedures for binational and multinational public health collaboration. Through 2 multinational meetings, regular district-level binational meetings, and fieldwork to characterize population movement and connectivity patterns, the countries improved cross-border public health coordination. Across 3 sequential cross-border Lassa fever outbreaks identified in Benin or Togo between February 2017 and March 2019, the 3 countries improved their collection and sharing of patients' cross-border travel histories, shortened the time between case identification and cross-border information sharing, and streamlined multinational coordination during response efforts. Notably, they refined collaborative efforts using lessons learned from the January to March 2018 Benin outbreak, which had a 100% case fatality rate among the 5 laboratory-confirmed cases, 3 of whom migrated from Nigeria across porous borders when ill. Aligning countries' expectations for sharing public health information would assist in reducing the international spread of communicable diseases by facilitating coordinated preparedness and responses strategies. Additionally, these binational and multinational strategies could be made more effective by tailoring them to the unique cultural connections and population movement patterns in the region.