Prevention of travellers' diarrhoea by oral B-subunit/whole-cell cholera vaccine.
B-subunit/whole-cell cholera vaccine (BS-WC) has been shown to give Bangladeshi mothers and children only 3 months' protection against severe diarrhoea due to enterotoxigenic Escherichia coli (ETEC). Since a long-lasting effect is not necessary for protection against travellers' diarrhoea, a prospective double-blind study was conducted among tourists who went to Morocco from Finland. 307 tourists received two oral doses of BS-WC, whereas 308 controls received a placebo before departure. A research team went out with tourists and a laboratory for enteric pathogens was set up on location. A faecal specimen was taken from 100 randomly selected subjects before departure, from all travellers with diarrhoea, and routinely after return. Enteropathogenic bacteria were not isolated from any of the pre-departure specimens but were present during or after the holiday in 47% of tourists with travellers' diarrhoea, and in 14% of those without diarrhoea. BS-WC induced a 52% protection (p = 0.013) against diarrhoea caused by ETEC. The protection was better for mixed infections (65%, p = 0.016). The protective efficacy against a combination of ETEC and any other pathogen was 71% (p = 0.02), and that against ETEC plus Salmonella enterica even better at 82% (p = 0.01). Partial protection against travellers' diarrhoea is thus obtainable by active immunisation with BS-WC.
National Public Health Institute, Helsinki, Finland.
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Peltola
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Siitonen
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Kyrönseppä
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Simula
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Mattila
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Oksanen
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Kataja
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Cadoz
D000284:Administration, Oral; D000328:Adult; D002772:Cholera Toxin / Q000008:administration & dosage* / Q000009:adverse effects; D022121:Cholera Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D003967:Diarrhea / Q000382:microbiology / Q000517:prevention & control*; D005243:Feces / Q000382:microbiology; D006801:Humans; D007115:Immunization Schedule; D010446:Peptide Fragments / Q000008:administration & dosage* / Q000009:adverse effects; D010865:Pilot Projects; D011446:Prospective Studies; D013997:Time Factors; D014195:Travel; D014611:Vaccination / Q000009:adverse effects
D022121:Cholera Vaccines; D010446:Peptide Fragments; C050310:cholera toxin, B subunit (50-64); D002772:Cholera Toxin