Effectiveness of hygiene kit distribution to reduce cholera transmission in Kasaï-Oriental, Democratic Republic of Congo: a prospective cohort study and process evaluation

Prospective cohort study

Household contacts of cholera cases are at a greater risk of Vibrio cholerae infection than the general population. There is currently no agreed standard of care for household contacts, despite their high risk of infection, in cholera response strategies such as case-area targeted interventions (CATI). In 2018, hygiene kit distribution and health promotion was recommended by Médecins Sans Frontières for admitted patients and accompanying household members upon admission to the health care facilities, as part of an overall response to a cholera outbreak in the Democratic Republic of Congo (DRC).

To investigate the effectiveness of the intervention and risk factors for cholera infection, we conducted a prospective cohort study and followed household contacts of cholera patients for 7-days after the patient sought care. Clinical surveillance was based on reported symptoms of cholera and diarrhoea, and environmental surveillance was conducted through the collection of food and water samples. All analyses were stratified by the receipt of the hygiene kit and compliance of use.

Multivariate analysis suggested evidence of a dose-response relationship with increased kit use associated with decreased risk of suspected cholera: household contacts in the high kit-use group had a 66% lower incidence of suspected cholera, the mid-use group had a 53% lower incidence and low-use group had 22% lower incidence, compared to household contacts without a kit. Drinking water contamination was significantly reduced among households in receipt of a kit. There was no significant effect on self-reported diarrhoea or food contamination.

The integration of a hygiene kit intervention to case-households, may be effective in reducing cholera transmission among household contacts and environmental contamination within the household. Further work is required to evaluate other proactive localised distribution among patients and case-households or to households surrounding those case-households to optimise future cholera response programmes in emergency contexts.

Process evaluation

Cholera remains a leading cause of infectious disease outbreaks globally, and a major public health threat in complex emergencies. Hygiene kits distributed to cholera case-households have previously shown an effect in reducing cholera incidence and are recommended by Médecins Sans Frontières (MSF) for distribution to admitted patients and accompanying household members upon admission to health care facilities (HCFs).

This process evaluation documented the implementation, participant response and context of hygiene kit distribution by MSF during a 2018 cholera outbreak in Kasaï-Oriental, Democratic Republic of Congo (DRC). The study population comprised key informant interviews with seven MSF staff, 17 staff from other organisations and a random sample of 27 hygiene kit recipients. Structured observations were conducted of hygiene kit demonstrations and health promotion, and programme reports were analysed to triangulate data.

Between Week (W) 28-48 of the 2018 cholera outbreak in Kasaï-Oriental, there were 667 suspected cholera cases with a 5% case fatality rate (CFR). Across seven HCFs supported by MSF, 196 patients were admitted with suspected cholera between W43-W47 and hygiene kit were provided to patients upon admission and health promotion at the HCF was conducted to accompanying household contacts 5-6 times per day. Distribution of hygiene kits was limited and only 52% of admitted suspected cholera cases received a hygiene kit. The delay of the overall response, delayed supply and insufficient quantities of hygiene kits available limited the coverage and utility of the hygiene kits, and may have diminished the effectiveness of the intervention. The integration of a WASH intervention for cholera control at the point of patient admission is a growing trend and promising intervention for case-targeted cholera responses.

These two complimentary studies in the Democratic Republic of Congo (DRC) evaluated the effectiveness of hygiene kit distribution to admitted cholera patients and their households at health care facilities, and the implementation and receipt of the overall cholera response.

The study followed household contacts of cholera patients for 7-days after the cholera patient sought care and received the intervention, collected data on reported symptoms of cholera and diarrhoea, and collected environmental samples of food and water to test for contamination. One of the studies examined the effectiveness of the hygiene kit distribution on the incidence of cholera and diarrhoeal disease and on food and water contamination. The other study collected quantitative data on intervention reach and distribution and qualitative data on receipt of the intervention by the study population. This study examined the challenges and successes to intervention delivery and receipt by the population.

Integration of the hygiene kits at the point of admission of suspected cases is possible, and both an effective and promising intervention for case-targeted cholera control. There was a 66% lower incidence of cholera among the population who received and frequently used the hygiene kit. There was positive response, use and adherence to hygiene kits by households. However, there were barriers to the timely supply, inadequate availability and consequent limited coverage of the hygiene kits. Further work is required to identify ways to improve implementation and delivery of this promising intervention.

The research may help responding agencies decide what types of intervention to include in their emergency cholera response programmes.