Effectiveness of the WC/rBS oral cholera vaccine in the prevention of traveler's diarrhea

Abstract

Objective: Traveler’s diarrhea (TD) is the most frequent disease among people from industrialized countries who travel to less developed ones, especially sub-Saharan Africa, Southern Asia and South America. The most common bacteria causing TD is enterotoxigenic Escherichia coli (ETEC). The WC/rBS cholera vaccine (Dukoral®) has been shown to induce cross-protection against ETEC by means of the B subunit of the cholera toxin. The aim of the study was to evaluate the effectiveness of the WC/rBS cholera vaccine in preventing TD.Methods: Between May 1 and September 30 (2007), people seeking pre-travel advice in ten Spanish international vaccination centers were included in a prospective cohort study of travelers to cholera risk countries. The incidence rates of TD were adjusted for variables whose frequencies were statistically different (entry point 0.10) between the vaccinated and non-vaccinated cohorts.Findings: The vaccinated cohort (n = 544 travelers) included people vaccinated with the WC/rBS cholera vaccine, and the non-vaccinated cohort (n = 530 travelers) by people not vaccinated. The cumulative incidence rate of TD was 1.69 in vaccinated and 2.14 in non-vaccinated subjects. The adjusted relative risk of TD in vaccinated travelers was 0.72 (95% CI: 0.58–0.88) and the adjusted vaccination effectiveness was 28% (95% CI: 12–42).Conclusions: The WC/rBS cholera vaccine prevents TD in 2 out of 7 travelers (preventive fraction: 28%). The number needed to vaccinate (NNV) to prevent 1 case of TD is 10.

Traveler’s Diarrhea

“…19 In a recent non-randomized evaluation, the vaccine was found to provide 28% protection against TD. 20 Several vaccine candidates against ETEC are in various phases of development, including consideration of a combined ETEC/ Shigella vaccine, targeting both travelers and children living in endemic countries. 21 …”

International Travelers’ Sociodemographic, Health, and Travel Characteristics: An Italian Study

“…The results suggest that WC/rBS vaccination of travelers to high-risk areas is associated with an absolute reduction of 28% in the risk of traveler's diarrhea. 30 In the study conducted by Aubry et al, 23 the percentages of other vaccinations were higher, especially for hepatitis B virus (4.1%), typhoid fever (37.1%), hepatitis A virus (41.5%), Japanese encephalitis (0.6%), and rabies (5.6%).…”

Imported cholera with acute renal failure after a short business-trip to the Philippines, Germany, October 2015

“…Besides pre-travel advice on general water and food precautions, the German Society for Tropical Medicine and International Health (DTG) recommends cholera vaccination for travellers to areas with current cholera outbreaks [11]. Oral cholera vaccination has also been shown to provide some protection against traveller's diarrhoea [12], but a recent systematic review of randomised controlled trials concluded that sufficient evidence is still lacking for its use to protect travellers against diarrhoea caused by enterotoxigenic Escherichia coli [13].…”