Field trial of a locally produced, killed, oral cholera vaccine in Vietnam.
Lancet
; 349(9047): 231-5, 1997 Jan 25.
Article
en En
| MEDLINE
| ID: mdl-9014909
ABSTRACT
PIP: Vibrio cholera 01, El Tor biotype, entered Vietnam in 1964 and during 1990-94 an average of 3240 cases were reported annually with a case-fatality rate of about 1%. The efficacy of an inexpensive, killed whole-cell cholera vaccine developed in Vietnam was assessed in a large-scale, open field trial in the city of Hue. The vaccine contained V. cholera 01 constituents: heat-killed V. cholera Inaba, heat-killed V. cholera Ogawa, and formalin-killed V. cholera Inaba. All 134,453 residents, aged 1 year or older, of 22,653 households in 19 communes were eligible to take part in the trial. Alternate households were assigned vaccine (67,395 people; 77% received 2 doses per person) or no vaccine (67,058 people serving as controls) during December 1992 and January 1993 by 80 vaccination teams. Following the vaccination no cases of cholera were detected until late August 1993. Between August 20 and October 4, 1993, there were 129 cases of cholera requiring inpatient care among age-eligible participants. The isolates were 01 serogroup and Ogawa serotype. There were 37 cases of cholera in the vaccine group and 92 cases in the control group. The risk of cholera was 0.5/1000 and 1.4/1000, respectively. The protective impact was 60% (95% confidence interval [CI] 40-73; p 0.001). Among 51,975 recipients of 2 vaccine doses the protective efficacy was 66% (CI 46-79; p 0.001). The protective efficacy was similar for children 1-5 years old (68%) and for older people (66%). The protective efficacy was somewhat higher among the vaccinated living in homes with unclean water sources (74% vs. 62%). The protective efficacy was also higher against severe than against non-severe cholera (76% vs. 58%). Oral killed whole-cell vaccines can protect against El Tor type cholera in children who are highest risk. The government has lately added a killed V. cholera 0139 strain to the existing formulation. Phase 2 tests of safety are under way, and a large-scale, randomized, double-blind field trial will start in 1997.
Palabras clave
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Vacunas contra el Cólera
/
Cólera
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Países en Desarrollo
Tipo de estudio:
Clinical_trials
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Observational_studies
/
Prognostic_studies
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Risk_factors_studies
/
Screening_studies
Aspecto:
Determinantes_sociais_saude
Límite:
Adolescent
/
Adult
/
Child
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Child, preschool
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Female
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Humans
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Infant
/
Male
País/Región como asunto:
Asia
Idioma:
En
Revista:
Lancet
Año:
1997
Tipo del documento:
Article
País de afiliación:
Vietnam
Pais de publicación:
Reino Unido