Kinetics of vibriocidal antibody responses among cholera patients in Goma, the Democratic Republic of Congo.

Cholera is a diarrheal disease that continues to burden vulnerable populations globally, primarily due to lack of clean water, optimal sanitation and adequate health infrastructure. Understanding the kinetics of antibody responses elicited by toxigenic infection can inform the Sero-epidemiological estimation of disease burden and impact of vaccination efforts. While antibody kinetics have been well-described in South Asia, such studies based in Africa are lacking, despite the ongoing prevalence of cholera in that region. We enrolled stool culture-positive cholera patients admitted to cholera treatment centers in Goma, Democratic Republic of Congo (DRC) between August 2020 and October 2023. Blood samples were collected upon enrollment and during follow-up home visits. We performed vibriocidal assays against O1 Inaba and Ogawa on 212 serum samples from 116 patients, 101 of whom had serotype information available (53% Male; 62% Female, Median age 8 (IQR 4-18). Vibriocidal antibody responses peaked between day 7 and 40 post symptom onset and then waned, with nearly all samples declining to a titer of 320 or lower by day 90, and 160 or lower by day 180. We used a Bayesian exponential decay model to show that there is an approximately 88% probability of a slower decay in participants over 5 years of age compared to younger aged subjects. Our findings corroborate the findings of prior studies conducted in hyperendemic areas in South Asia and provide critical data to inform the timing of vaccination campaigns and interpretation of serosurveillance results in African populations.