Estudio primario
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Background & Research Objectives In late 2005 and mid-2008, Population Services International/Malawi (PSI/Malawi) conducted a household survey designed to monitor trends in the administration of ORS to children under the age of five age who had dirrahea in the last two weeks. The 2008 survey was a follow-up to a survey conducted in 2005. Description of Intervention PSI/Malawi is engaged in the social marketing of a range of health products that directly address significant health concerns faced by Malawians, such as diarrhea disease. These products consist of Chishango condoms, Thanzi ORS WaterGuard (point-of-use water treatment). PSI/Malawi has also launched WaterGuard Powder), CARE female condoms, Safeplan injectollte and Microllette. The products are distributed via a range of traditional and non-traditional outlets, primarily employing Malawi's commercial distribution network and the Health facilities network. Methodology This study design was based on a stratified multi-stage cluster sampling approach. The total sample size for the study was 4181. This was divided by place of residence (urban and rural) in a ratio of 1 to 4, proportionally to size1 .Results are presented in standard PSI Dashboard tables
Estudio primario
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Groups of 122 Peruvian adults of low socioeconomic level (SEL) and 125 of high SEL received a randomly allocated 5 x 10(9)- or 5 x 10(8)-CFU dose of CVD 103-HgR live oral cholera vaccine or a placebo. The vaccine was well tolerated. Vibriocidal seroconversions occurred in 78% of high-SEL and 72% of low-SEL subjects who ingested the high dose and in 78 and 49%, respectively, of those who received the low dose.
Estudio primario
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Enterotoxigenic Escherichia coli (ETEC), which produces heat labile toxin (LT) and/or heat stable toxin (ST), is considered to be the most common known cause of travellers' diarrhoea (TD). Owing to the antigenic similarity between cholera toxin and LT, immunization with inactivated oral B-subunit/whole-cell cholera vaccine (BS-WC) offers short term (3 months) but significant (>67%) protection against TD caused by LT-related ETEC. Since it expresses the cholera toxin B (CTB) subunit, the live attenuated oral cholera vaccine strain CVD 103-HgR, may induce similar protection. A trial was performed to determine if CVD 103-HgR live oral cholera vaccine would provide a protective efficacy of at least 50% against TD. In addition, the protective efficacy of the vaccine against TD specifically due to LT-ETEC and LT/ST-ETEC was determined. Volunteers (n=134) travelling to Indonesia, India, Thailand or West-Africa were randomised to receive either a placebo (n=65) or the vaccine (n=69). In the placebo group, 46% reported an episode of diarrhoea, compared to 52% in the vaccine group. No significant group differences were found with regard to incidence, duration or severity of all caused TD or ETEC-associated TD. However, ETEC-associated TD occurred earlier in the placebo group (median 5 days), compared to the vaccine group (median 15 days). In conclusion, CVD 103-HgR live oral cholera vaccine failed to provide a 50% protection against TD. This study does not exclude that the vaccine may offer a short-lived protection against ETEC-associated TD. However, the power of the study was limited by the unexpected low incidence of LT-ETEC-associated diarrhoea (9% of all TD) compared to ST-associated TD (24% of all TD).
Estudio primario
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We assessed serologic responses to an oral, killed whole-cell enterotoxigenic Escherichia coli plus cholera toxin B-subunit (ETEC-rCTB) vaccine in 73 Egyptian adults, 105 schoolchildren, and 93 preschool children. Each subject received two doses of vaccine or placebo 2 weeks apart, giving blood before immunization and 7 days after each dose. Plasma antibodies to rCTB and four vaccine-shared colonization factors (CFs) were measured by enzyme-linked immunosorbent assay. Immunoglobulin A (IgA) antibodies to rCTB and CFA/I were measured in all subjects, and those against CS1, CS2, and CS4 were measured in all children plus a subset of 33 adults. IgG antibodies to these five antigens were measured in a subset of 30 to 33 subjects in each cohort. Seroconversion was defined as a >2-fold increase in titer after vaccination. IgA and IgG seroconversion to rCTB was observed in 94 to 95% of adult vaccinees, with titer increases as robust as those previously reported for these two pediatric cohorts. The proportion showing IgA seroconversion to each CF antigen among vaccinated children (range, 70 to 96%) and adults (31 to 69%), as well as IgG seroconversion in children (44 to 75%) and adults (25 to 81%), was significantly higher than the corresponding proportion in placebo recipients, except for IgA responses to CS2 in adults. IgA anti-CF titers peaked after one dose in children, whereas in all age groups IgG antibodies rose incrementally after each dose. Independently, both preimmunization IgA titer and age were inversely related to the magnitude of IgA responses. In conclusion, serologic responses to the ETEC-rCTB vaccine may serve as practical immune outcome measures in future pediatric trials in areas where ETEC is endemic.
Estudio primario
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Recombinant A-B+ Vibrio cholerae O1 strain CVD 103-HgR is a safe, highly immunogenic, single-dose live oral vaccine in adults in industrialized countries, Safety, excretion, immunogenicity, vaccine transmissibility, and environmental introduction ofCVD 103-HgR were investigated among 24- to 59-month-old children in Jakarta. In 81 households, 1 child was randomly allocated a single dose of vaccine (5 x 109 cfu) and another, placebo. Additionally, 139 unpaired children were randomly allocated vaccine or placebo. During 9 days of follow-up, diarrhea or vomiting did not occur more often among vaccinees than controls. Vaccine was minimally excreted and was isolated from no controls and from 1 (0.6%) of 177 unvaccinated family contacts. A 4-fold or higher rise in serum vibriocidal antibody was observed in 75% of vaccinees (10-fold rise in geometric mean titer over baseline). Of 135 paired placebo recipients or household contacts, 5 had vibriocidal seroconversions. Moore swabs placed in sewers and latrines near 97 households failed to detect vaccine. These observations pave the way for a large-scale field trial of efficacy.
Estudio primario
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The effects of concomitant administration of antimalarial drugs, oral polio vaccine, or yellow fever vaccine on the immune response elicited by the Vibrio cholerae CVD103-HgR and Salmonella typhi Ty21a live oral vaccines were investigated. Healthy adults were immunized with CVD103-HgR alone or combined with Ty21a. Subjects were randomized to simultaneously receive mefloquine, chloroquine or proguanil, or oral polio or yellow fever vaccine. The vibriocidal antibody seroconversion rate was significantly reduced (P = .008) only in the group that received chloroquine with the CVD103-HgR. The geometric mean vibriocidal antibody titer was significantly decreased in the groups that received chloroquine (P = .001) or mefloquine (P = .02) compared with titers in groups that received CVD103-HgR alone. However, similar immunosuppressive effects were not observed in the groups immunized with Ty21a and CVD103-HgR. Only the concomitant administration of proguanil effected a significant (P = .013) decline in the anti-S. typhi lipopolysaccharide antibody response. These results indicate that chloroquine and proguanil should not be simultaneously administered with the CVD103-HgR and Ty21a vaccine strains, respectively.
Estudio primario
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The B subunit (BS) of cholera toxin and that of the heat-labile enterotoxin (LT) of enterotoxigenic Escherichia coli (ETEC) are antigenically similar. We therefore assessed whether a combined cholera toxin BS/whole-cell (BS-WC) oral vaccine against cholera conferred cross-protection against LT-producing ETEC (LT-ETEC) diarrhea in a randomized, double-blind field trial among rural Bangladeshi children and women. The 24,770 persons who ingested two or more doses of BS-WC vaccine were compared with 24,842 controls who took two or more doses of killed whole-cell (WC) oral cholera vaccine. Sixty-seven percent fewer episodes of LT-ETEC diarrhea were noted in the BS-WC group than in the WC group during short-term (three-month) follow-up (P less than .01), but no reduction was evident during the ensuing nine months. Short-term protection was particularly notable against LT-ETEC diarrhea causing life-threatening dehydration (protective efficacy, 86%; P less than .05).
Estudio primario
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We conducted a double-blind, placebo-controlled, randomized crossover study to evaluate the safety and immunogenicity of a single 5 x 10(8)-CFU dose of live oral recombinant cholera vaccine CVD 103-HgR in 94 North American adults. The vaccine was well tolerated without associated adverse reactions. Despite minimal fecal excretion of vaccine, 97% of subjects exhibited serum vibriocidal antibody and 72% had antitoxin responses.
Estudio primario
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Immune responses after one and two doses of the reformulated killed oral cholera vaccine were measured in a double-blind, randomized, placebo-controlled trial of 77 adults aged 18–40 years and 77 children aged 1–17 years residing in Kolkata, India. 65% of adults and 87% of children and 46% of adults and 82% of children exhibited a ≥4-fold rise in serum Vibrio cholerae O1 vibriocidal antibody titers from baseline following dose 1 and 2, respectively. Responses to V. cholerae O139 were less pronounced but followed a similar pattern. We demonstrate that in a cholera-endemic area, the vaccine elicited vibriocidal responses after a single-dose of the vaccine.
Estudio primario
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This study examined the comparative efficacies of rice-based oral rehydration solution (R-ORS) and glucose-based oral rehydration solution (G-ORS) in the management of severe cholera due to Vibrio cholerae O139 Bengal that causes epidemic cholera in many developing countries. Stool culture-proved adult male patients with severe cholera due to V. cholerae O139 Bengal were randomly assigned in a 1:1 ratio to receive either R-ORS or G-ORS after their initial rehydration with intravenous (i.v.) fluid and subsequently four hours of observation. They also received the usual hospital diet and tetracycline capsules (500 mg 6 hourly for three days) immediately after their enrollment in the study. The primary outcomes for observation were stool output during the first 24 hours after intervention and treatment failure as measured by the incidence of re-institution of i.v. fluid after initiation of trial therapy and duration of diarrhoea. Of 113 patients finally included in the study, 57 received R-ORS and 56 G-ORS. The admission characteristics of the two treatment groups were comparable. No significant differences in the first 24 hours of median (inter-quartile range) stool output [179 (67-206) g/kg in R-ORS group vs 193 (80-237) g/kg in G-ORS group; p = 0.52], incidences of unscheduled i.v. fluid requirement [21% (12/57) in R-ORS group vs 25% (14/56) in G-ORS group; p = 0.78], and median (inter-quartile range) duration of diarrhoea [32 (24-48) hours in R-ORS group vs 32 (24-56) hours in G-ORS group; p = 0.64] were observed. It is concluded that rice-based ORS is effective but not superior to standard glucose-based ORS in the management of adult males with severe cholera due to V. cholerae O139 Bengal.