Descriptive epidemiology and mortality risk factors of COVID-19 outbreak in Delta State, Nigeria, March - August 2020

Introduction: The highly contagious Coronavirus Disease 2019 (COVID-19) was first confirmed in Nigeria on February 27, 2020. In Delta State, the first COVID-19 case was recorded on April 7, 2020, which spread across the state. We characterized the COVD-19 pandemic in Delta State in terms of person, place, and time, and determined the risk factors for COVID-19 mortality. Methods: We conducted a retrospective analysis of COVID-19 pandemic in Delta State between March 23 to August 17, 2020. We obtained line-lists of 5,917 COVID-19 patients, cleaned and analyzed sociodemographic, clinical characteristics and outcome variables using IBM SPSS Statistics 25. We calculated frequencies, proportions, mean and standard deviation (SD). Bivariate and multivariate logistics regression analysis were conducted to determine the risk factors of COVID-19 mortality, adjusted-odds-ratios were reported at 95% confidence interval and p-value set at 5% significance level. Results: From March-August 2020, 1,605 confirmed COVID-19 cases and 47 deaths (case-fatality-rate 2.9%) were recorded. Majority were aged 20-39 years 675 (42.1%) while 1,064 (66.3%) were males (mean age 39±15years). Persons aged ≥60years were more likely to die from COVID-19 than younger cases (aOR: 11.0; 95% CI: 4.9-24.4) while Symptomatic positive cases at time of test were more likely to die than those who were not (aOR: 3.2; 95% CI: 1.3-7.5). Conclusion: Males in the youthful age-group were mostly affected. Independent predictors of mortality were being elderly or symptomatic at time of testing. Strengthening case management to target symptomatic patients and intensifying sensitization activities targeting youthful males and elderly persons, are important to reduce mortality

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

The One Health approach to incident management of the 2019 Lassa fever outbreak response in Nigeria.

Globally, effective emergency response to disease outbreaks is usually affected by weak coordination. However, coordination using an incident management system (IMS) in line with a One Health approach involving human, environment, and animal health with collaborations between government and non-governmental agencies result in improved response outcome for zoonotic diseases such as Lassa fever (LF). We provide an overview of the 2019 LF outbreak response in Nigeria using the IMS and One Health approach. The response was coordinated via ten Emergency Operation Centre (EOC) response pillars. Cardinal response activities included activation of EOC, development of an incident action plan, deployment of One Health rapid response teams to support affected states, mid-outbreak review and after-action review meetings. Between 1st January and 29th December 2019, of the 5057 people tested for LF, 833 were confirmed positive from 23 States, across 86 Local Government Areas. Of the 833 confirmed cases, 650 (78%) were from hotspot States of Edo (36%), Ondo (26%) and Ebonyi (16%). Those in the age-group 21-40 years (47%) were mostly affected, with a male to female ratio of 1:1. Twenty healthcare workers were affected. Two LF naïve states Kebbi and Zamfara, reported confirmed cases for the first time during this period. The outbreak peaked earlier in the year compared to previous years, and the emergency phase of the outbreak was declared over by epidemiological week 17 based on low national threshold composite indicators over a period of six consecutive weeks. Multisectoral and multidisciplinary strategic One Health EOC coordination at all levels facilitated the swift containment of Nigeria's large LF outbreak in 2019. It is therefore imperative to embrace One Health approach embedded within the EOC to holistically address the increasing LF incidence in Nigeria

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

BackgroundLassa 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.MethodsWe 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.ResultsWe 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.ConclusionLassa 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

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

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

Additional file 1 of Epidemiological description of and response to a large yellow fever outbreak in Edo state Nigeria, September 2018 - January 2019

Additional file 1: Supplementary Fig. 1. Suspected Yellow fever cases in Edo State by LGAs September 2018 – January 2019. Supplementary Fig. 2. Yellow fever attack rate by LGA in Edo State September 2018 - January 2019. Supplementary Fig. 3. Age-sex distribution of Yellow Fever cases in Edo State September 2018 - January 2019