Trend of Lassa fever cases and factors associated with mortality in Liberia, 2016 - 2021: a secondary data analysis.

Introduction: Lassa fever (LF) is endemic in Liberia and is immediately reportable. Suspected cases are confirmed at the National Public Health Reference Laboratory. However, there is limited information on the trend and factors associated with mortality. We described the epidemiological characteristics of LF cases and determined factors associated with mortality in Liberia from 2016 to 2021. Methods: we reviewed 867 case-based LF surveillance data from 2016 to 2021 obtained from the National Public Health Institute of Liberia (NPHIL). The cases that met the suspected LF case definition were tested with RT-PCR. Using Epi Info 7.2.5.0. We conducted univariate, bivariate, and multivariate and analysis. We calculated frequencies, proportions. Positivity rate, case fatality rate, and factors associated with LF mortality using chi-square statistics and logistics regression at 5% level of significance. Results: eighty-five percent (737/867) of the suspected cases were tested and 26.0% (192/737) were confirmed LF positive. The median age of confirmed LF cases was 21(IQR: 12-34) years. Age 10-19 years accounted for 24.5% (47/192) and females 54.2% (104/192). Bong 33.9% (65/192), Grand Bassa 31.8% (61/192), and Nimba counties, 21.9% (42/192) accounted for most of the cases. The median duration from symptom onset to hospital admission was 6 (IQR: 3-9) days. A majority, 66% (126/192) of the cases were reported during the dry season (October-March) and annual incidence was highest at 12 cases per 1,000,000 population in 2019 and 2020. The overall case fatality rate was 44.8%. Non-endemic counties, Margibi, 77.8% and Montserrado, 66.7% accounted for the highest case fatality rate (CFR), while 2018, 66.7% and 2021, 60.0% recorded the highest CFR during the period. Age ≥30 years (aOR=2.1,95% CI: 1.08-4.11, p=0.027) and residing in Grand Bassa County (aOR=0.3, 95% CI: 0.13-0.73, p=0.007) were associated with LF mortality. Conclusion: Lassa fever was endemic in three of the fifteen counties of Liberia, case fatality rate remained generally high and widely varied. The high fatality of LF has been reported to the NPHIL and is currently being further investigated. There is a need to continuously train healthcare workers, especially in non-endemic counties to improve the LF treatment outcome.

Evaluation of Ebola virus disease surveillance system capability to promptly detect a new outbreak in Liberia.

INTRODUCTION: Liberia was heavily affected by the 2014-2016 Ebola virus disease (EVD) outbreak. With substantial investments in interventions to combat future outbreaks, it is hoped that Liberia is well prepared for a new incursion. We assessed the performance of the current EVD surveillance system in Liberia, focusing on its ability to promptly detect a new EVD outbreak. METHODS: We integrated WHO and US Centers for Disease Control and Prevention guidelines for public health surveillance system evaluation and used standardised indicators to measure system performance. We conducted 23 key informant interviews, 150 health facility assessment surveys and a standardised patient (SP) study (19 visits) from January 2020 to January 2021. Data were summarised and a gap analysis conducted. RESULTS: We found basic competencies of case detection and reporting necessary for a functional surveillance system were in place. At the higher (national, county and district) levels, we found performance gaps in 2 of 6 indicators relating to surveillance system structure, 3 of 14 indicators related to core functions, 1 of 5 quality indicators and 2 of 8 indicators related to support functions. The health facility assessment found performance gaps in 9 of 10 indicators related to core functions, 5 of 6 indicators related to support functions and 3 of 7 indicators related to quality. The SP simulations revealed large gaps between expected and actual practice in managing a patient warranting investigation for EVD. Major challenges affecting the system's operations across all levels included limited access to resources to support surveillance activities, persistent stock out of sample collection materials and attrition of trained staff. CONCLUSION: The EVD surveillance system in Liberia may fail to promptly detect a new EVD outbreak. Specific improvements are required, and regular evaluations recommended. SP studies could be crucial in evaluating surveillance systems for rarely occurring diseases that are important to detect early.

COVID-19 reinfection in Liberia: Implication for improving disease surveillance.

COVID-19 remains a serious disruption to human health, social, and economic existence. Reinfection with the virus intensifies fears and raises more questions among countries, with few documented reports. This study investigated cases of COVID-19 reinfection using patients' laboratory test results between March 2020 and July 2021 in Liberia. Data obtained from Liberia's Ministry of Health COVID-19 surveillance was analyzed in Excel 365 and ArcGIS Pro 2.8.2. Results showed that with a median interval of 200 days (Range: 99-415), 13 out of 5,459 cases were identified and characterized as reinfection in three counties during the country's third wave of the outbreak. Eighty-six percent of the COVID-19 reinfection cases occurred in Montserrado County within high clusters, which accounted for over 80% of the randomly distributed cases in Liberia. More cases of reinfection occurred among international travelers within populations with high community transmissions. This study suggests the need for continued public education and surveillance to encourage longer-term COVID-19 preventive practices even after recovery.