Goma

Researchers are studying the impact of oral cholera vaccine mass campaigns in two locationsone urban and one ruralin the Democratic Republic of the Congo DRC. The goal is to understand how these vaccination efforts affect the control of cholera in areas where the disease is common and causes high mortality. This includes gathering key evidence to guide future cholera vaccine strategies in similar regions. The project includes three parts clinical surveillance to track cholera cases in selected hotspots, regular blood tests to detect recent cholera infections, and monitoring individuals who test positive for cholera bacteria, whether they show symptoms or not, including their household members. It focuses on assessing cholera incidence after vaccination campaigns and studying how long vaccinated and unvaccinated people shed the bacteria, as well as the spread within households. Participants will be patients attending selected cholera treatment centers and their household members if they test positive for cholera bacteria. Researchers will measure cholera transmission rates over two years, monitor bacterial shedding for up to one year, and analyze the genetic diversity of cholera strains. The study will develop sustainable monitoring methods to track the effectiveness of cholera control programs. Participation involves clinical evaluations and follow-up for up to two years.

Researchers are investigating whether adults in the Democratic Republic of Congo who were previously vaccinated against Ebola virus with either the ZabdenoMvabea4 or Ervebo4 vaccine schedules can be safely and effectively boosted using either the same homologous or a different heterologous vaccine schedule. This randomized controlled trial aims to compare immune responses and safety profiles between these booster approaches, hypothesizing that heterologous boosters will produce similar antibody and cellular responses without added safety concerns. The study includes 624 participants divided into two groups based on their initial vaccination 312 with ZabdenoMvabea4 and 312 with Ervebo4. Each group is further randomized to receive either a single intramuscular booster of the same vaccine or the alternate one, resulting in four study arms. Booster doses are given once, with doses of 0.5 ml for Zabdeno4 and 1 ml for Ervebo4. Blood samples will be collected at multiple pre-set visits over six months to measure antibody levels and cellular immune responses. An additional 50 non-vaccinated participants will be enrolled to assist in laboratory assay optimization. Participants will attend clinic visits at specific times during the six-month follow-up to provide blood samples and undergo safety assessments, including monitoring for adverse events and vital signs. The study will evaluate antibody levels 21 days after booster vaccination as the primary outcome, along with various secondary measures of immune response and safety checks at several timepoints. Safety and tolerability will be closely recorded, and participant medical history and medication use will be reviewed to understand factors influencing vaccine response.