Infectious Disease
Assessing the Emerging Trend of Lassa Fever in Liberia (2016-2022) Bendu Sherman* Bendu Sherman Danielle Gartner
The case fatality rate (CFR) of Lassa fever in Liberia is much higher than the worldwide CFR of 1% reported by the World Health Organization (WHO). In recent years, the trend in Lassa Fever cases has also changed. To better understand this emerging trend, we described the general characteristics and seasonal variation in cases and the CFR over time. We analyzed data from 350 cases across six counties in Liberia with a high prevalence of Lassa fever cases. The data was collected through a surveillance system that includes hospitals, the National Reference Lab, and the National Public Health Institute of Liberia (NPHIL). The data included information on suspected and confirmed Lassa Fever cases between 2016 and 2022, aggregated at the county level. 74.6% (n=261) were confirmed cases by the National Reference Lab, while 25.4% (n=89) were suspected cases. Among the confirmed cases, 39.5% (n=103) were under the age of 18 years, 54.4% (n=142) were female, and 41% (n=107) died. Additionally, 55.6% (n=145) of confirmed cases were reported during the dry season, and 91.6% (n=239) were from three counties – Bong, Grand Bassa, and Nimba. The highest overall CFR (62.50%) was reported in 2016, while the highest CFRs among confirmed cases were reported in 2018 (66.67%) and 2021 (60%). The lowest overall and confirmed CFRs were reported in 2022, 29.73% and 29.58%, respectively. The highest CFRs were observed in the dry season in 2016 (69.57%) and 2018 (60%). However, the CFRs in rainy and dry seasons declined in 2022. Lassa Fever is a significant public health issue in Liberia. While the CFRs reported in this work are significantly high, it is worth noting that the high CFR could be influenced by the presence of more severe cases in the case count. Most Lassa fever cases (~80%) are often asymptomatic or mild. Therefore, people visiting the hospital may have more severe cases of the disease.