66 Kinetics of Vibrio cholerae antibody responses among cholera patients in Goma, the Democratic Republic of Congo

Faculty Mentor: Daniel Leung (Internal Medicine, University of Utah)

Introduction

Cholera is a diarrheal disease that continues to burden vulnerable populations globally, primarily due to inadequate water and sanitation infrastructure. Understanding the kinetics of antibody responses elicited by Vibrio cholerae infection will inform estimation of disease burden by serosurveillance methods and targeting and timing of future vaccination efforts.

Methods

Patients presenting to cholera treatment centers in Goma, the Democratic Republic of Congo (DRC), with acute watery diarrhea between August 2020 and Mar 2022 were enrolled in the study and blood samples were collected during follow-up home visits approximately one week, four weeks, and six months after symptom onset.

Results

Out of the 1057 total collected samples, we performed vibriocidal assays against O1 Inaba and O1 Ogawa on 84 serum samples from patients with culture-confirmed V. cholerae infection (n= 35; 46% Male; 54% Female, Median age 8 (IQR 3-14), for which two or more timepoints were available; 26 of those 84 samples had a month six timepoint. Preliminary data analysis indicates that vibriocidal antibody responses were highest at the first collected timepoint (Ogawa Geometric Mean titers 105, range 5-10240), with a non-significant decrease in titers by week four (GM 96, 5-5120) and significantly lower titers at six months (GM 12, 5- 160).

Conclusions

Our findings highlight the potential that cholera patients in different regions of the world may have differing kinetics of antibody response, and by extension, potential differences in duration of immunity after infection or vaccination. Further studies into the kinetics of cholera antibody responses may inform the timing of vaccination campaigns and interpretation of serosurveillance results. Further analysis, including of additional serum samples, and stratification by vaccination status, age, and disease severity, are pending