C-reactive protein and association with disease severity in hospitalized adult patients with Lassa fever in Nigeria.

Objectives: Lassa fever (LF) poses a significant health burden in West Africa. The pathophysiology of LF and determinants of clinical spectrum of disease remain poorly understood. We performed a study to understand the correlation of blood inflammatory marker C-reactive protein (CRP), with LF disease severity.

Methods: A cross-sectional controlled study of adult patients with LF presenting to the Institute of Lassa Fever Research and Control at Irrua Specialist Teaching Hospital, Nigeria between January and April 2023. LF was confirmed using real-time polymerase chain reaction. Disease severity was classified as: severe disease = blood urea level >100 mg/dl and moderate disease = <100 mg/dl. CRP was measured using Tecan Infinite F50 ELISA system. Disease severity was correlated with CRP levels.

Results: A total of 64 adult patients with LF and 60 healthy controls were enrolled. There was no difference in the mean age (37.6 vs 35.2 years, = 0.10) and gender (male 53% vs 56%, = 0.82). CRP levels were significantly elevated in patients with LF (mean: 36.23 mg/l, SD: 4.56, %coefficient of variation [CV]: 12.59) compared with controls (mean: 5.42 mg/l, SD: 0.53, %CV: 9.78) ( = 0.000). CRP levels varied with disease severity, being significantly higher in patients with severe disease (28.57 mg/l, SD = 2.34; %CV = 8.19) than in those with moderately severe disease (12.34 mg/l, SD = 0.98; %CV = 7.94); ( = 0.001).

Conclusions: Inpatients with LF showed significant inflammation and elevated CRP levels, which correlated with disease severity. CRP could serve as a potential baseline marker in outbreak situations to trigger management decision-making to treat or not to treat considering limited ribavirin supplies. Given the inflammatory changes and correlation of elevated CRP levels with LF disease severity, larger controlled studies during outbreaks are required to assess use of CRP for more accurate triaging, including commencement of treatment.