Prevention of typhoid fever by existing improvements in household water, sanitation, and hygiene, and the use of the Vi polysaccharide typhoid vaccine in poor urban slums: results from a cluster-randomized trial

Journal article

Typhoid fever, an invasive bloodstream infection caused by Salmonella enterica serovar Typhi, remains a significant public health problem. ^1 – 4 Globally, there are approximately 12 million cases and 128,000 deaths each year, with almost all of the burden concentrated in low- and middle-income countries. ⁵ Infection occurs through ingestion of contaminated food or water, and transmission can be high in areas with an insufficient clean water infrastructure and limited access to sanitary facilities. We know that major improvements in municipal water, sanitation, and hygiene (WASH) have drastically reduced infectious disease transmission, including typhoid, and have prevented disease in affluent countries. ⁶ Empiric evidence from a Kolkata urban slum has demonstrated that improvements in household WASH occurring naturally, without a specific intervention, were predictive of reduced typhoid risk. ⁷ Several effective typhoid vaccines are now licensed and available, including two that are WHO prequalified: a vaccine consisting of Vi polysaccharide (ViPS) and one that is ViPS conjugated chemically to a tetanus toxoid. ⁸ Recognizing that current recommendations for control of typhoid in low- and middle-income countries emphasize the use of both effective typhoid vaccines and improvement of WASH, ⁹ we asked whether protection by an effective typhoid vaccine acted independently of protection conferred by better existing WASH, and whether these independent effects were complementary when implemented together in an urban slum where typhoid is endemic. A cluster-randomized trial of an effective typhoid vaccine, ViPS, conducted in an urban slum of Kolkata, India, provided a unique platform to address these questions.

Authors: Im, J; Khanam, F; Ahmmed, F; Kim, DR; Kang, S

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Society of Tropical Medicine and Hygiene
• Journal: American Journal of Tropical Medicine and Hygiene More from this journal
• Volume: 106
• Issue: 4
• Pages: 1149-1155
• Publication date: 2022-03-07
• Acceptance date: 2021-12-12
• DOI: 10.4269/ajtmh.21-1034
• EISSN: 1476-1645
• ISSN: 0002-9637
• Pmid: 35385827
• Language: English
• Keywords: typhoid fever; sanitation; hygiene; water; poverty areas; typhoid-paratyphoid vaccines; dietary carbohydrates