Prevention of Typhoid by Vi Conjugate Vaccine and Achievable Improvements in Household Water, Sanitation, and Hygiene: Evidence From a Cluster-Randomized Trial in Dhaka, Bangladesh.

Tasnuva Ahmed, John D Clemens, Firdausi Qadri, Florian Marks, Andrew J Pollard, Ashraful Islam Khan, Khalequ Zaman, Gideok Pak, Juyeon Park, Masuma Hoque, Asma Binte Aziz, Deok Ryun Kim, Fahima Chowdhury, Xinxue Liu, Sophie S Y Kang, Md Taufiqul Islam, Justin Im, Faisal Ahmmed, Farhana Khanam, Birkneh Tilahun Tadesse, Jerome H Kim

Journal: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 2022;75(10):1681-1687

PMID: 35412603

Free Full Text on PubMed Central View on PubMed

Abstract

BACKGROUND

Typhoid fever contributes to approximately 135 000 deaths annually. Achievable improvements in household water, sanitation, and hygiene (WASH) combined with vaccination using typhoid conjugate vaccines (TCVs) may be an effective preventive strategy. However, little is known about how improved WASH and vaccination interact to lower the risk of typhoid.

METHODS

A total of 61 654 urban Bangladeshi children aged 9 months to <16 years, residing in 150 clusters with a baseline population of 205 760 residents, were randomized 1:1 by cluster to Vi-tetanus toxoid TCV or Japanese encephalitis (JE) vaccine. Surveillance for blood culture-confirmed typhoid fever was conducted over 2 years. Existing household WASH status was assessed at baseline as Better or Not Better using previously validated criteria. The reduction in typhoid risk among all residents associated with living in TCV clusters, Better WASH households, or both was evaluated using mixed-effects Poisson regression models.

RESULTS

The adjusted reduced risk of typhoid among all residents living in the clusters assigned to TCV was 55% (95% confidence interval [CI], 43%-65%; P < .001), and that of living in Better WASH households, regardless of cluster, was 37% (95% CI, 24%-48%; P < .001). The highest risk of typhoid was observed in persons living in households with Not Better WASH in the JE clusters. In comparison with these persons, those living in households with Better WASH in the TCV clusters had an adjusted reduced risk of 71% (95% CI, 59%-80%; P < .001).

CONCLUSIONS

Implementation of TCV programs combined with achievable and culturally acceptable household WASH practices were independently associated with a significant reduction in typhoid risk.

CLINICAL TRIALS REGISTRATION

ISRCTN11643110.

Address: International Vaccine Institute, Seoul, Republic of Korea.; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.; Oxford Vaccine Group, Department of Pediatrics, University of Oxford, and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom.; Cambridge Institute of Therapeutic Immunology and Infectious Disease, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom.; Department of Microbiology and Parasitology, University of Antananarivo, Antananarivo, Madagascar.; Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany.; Fielding School of Public Health, University of California, Los Angeles, Los Angeles, California, USA.

DOI: 10.1093/cid/ciac289

Link outs

Free resources

Full Text Sources:

Subscription / membership required

Full Text Sources:

MeSH Terms: Humans, Child, Typhoid Fever, Vaccines, Conjugate, Sanitation, Water, Bangladesh, Typhoid-Paratyphoid Vaccines, Hygiene