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Efficacy of a low-cost, inactivated whole-cell oral cholera vaccine: results from 3 years of follow-up of a randomized, controlled trial.

ABSTRACT: Killed oral cholera vaccines (OCVs) have been licensed for use in developing countries, but protection conferred by licensed OCVs beyond two years of follow-up has not been demonstrated in randomized, clinical trials.We conducted a cluster-randomized, placebo-controlled trial of a two-dose regimen of a low-cost killed whole cell OCV in residents 1 year of age and older living in 3,933 clusters in Kolkata, India. The primary endpoint was culture-proven Vibrio cholerae O1 diarrhea episodes severe enough to require treatment in a health care facility. Of the 66,900 fully dosed individuals (31,932 vaccinees and 34,968 placebo recipients), 38 vaccinees and 128 placebo-recipients developed cholera during three years of follow-up (protective efficacy 66%; one-sided 95%CI lower bound?=?53%, p<0.001). Vaccine protection during the third year of follow-up was 65% (one-sided 95%CI lower bound?=?44%, p<0.001). Significant protection was evident in the second year of follow-up in children vaccinated at ages 1-4 years and in the third year in older age groups.The killed whole-cell OCV conferred significant protection that was evident in the second year of follow-up in young children and was sustained for at least three years in older age groups. Continued follow-up will be important to establish the vaccine's duration of protection.ClinicalTrials.gov NCT00289224.

SUBMITTER: Sur D

PROVIDER: S-EPMC3196468 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature

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Efficacy of a low-cost, inactivated whole-cell oral cholera vaccine: results from 3 years of follow-up of a randomized, controlled trial.

Sur Dipika D Kanungo Suman S Sah Binod B Manna Byomkesh B Ali Mohammad M Paisley Allison M AM Niyogi Swapan K SK Park Jin Kyung JK Sarkar Banawarilal B Puri Mahesh K MK Kim Deok Ryun DR Deen Jacqueline L JL Holmgren Jan J Carbis Rodney R Rao Raman R Nguyen Thu Van TV Han Seung Hyun SH Attridge Stephen S Donner Allan A Ganguly Nirmal K NK Bhattacharya Sujit K SK Nair G Balakrish GB Clemens John D JD Lopez Anna Lena AL

PLoS neglected tropical diseases 20111018 10

<h4>Background</h4>Killed oral cholera vaccines (OCVs) have been licensed for use in developing countries, but protection conferred by licensed OCVs beyond two years of follow-up has not been demonstrated in randomized, clinical trials.<h4>Methods/principal findings</h4>We conducted a cluster-randomized, placebo-controlled trial of a two-dose regimen of a low-cost killed whole cell OCV in residents 1 year of age and older living in 3,933 clusters in Kolkata, India. The primary endpoint was cultu ...[more]

PMID: 22028938

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Project description:BackgroundKilled whole-cell oral cholera vaccines (OCVs) are widely used for prevention of cholera in developing countries. However, few studies have evaluated the protection conferred by internationally recommended OCVs for durations beyond 2 years of follow-up.MethodsIn this study, we followed up the participants of a cluster-randomised controlled trial for 2 years after the end of the original trial. Originally, we had randomised 90 geographical clusters in Dhaka slums in Bangladesh in equal numbers (1:1:1) to a two-dose regimen of OCV alone (targeted to people aged 1 year or older), a two-dose regimen of OCV plus a water-sanitation-hygiene (WASH) intervention, or no intervention. There was no masking of group assignment. The WASH intervention conferred little additional protection to OCV and was discontinued at 2 years of follow-up. Surveillance for severe cholera was continued for 4 years. Because of the short duration and effect of the WASH intervention, we combined the two OCV intervention groups. The primary outcomes were OCV overall protection (protection of all members of the intervention clusters) and total protection (protection of individuals who got vaccinated in the intervention clusters) against severe cholera, which we assessed by multivariable survival models appropriate for cluster-randomised trials. This trial is registered on ClinicalTrials.gov, NCT01339845.FindingsThe study was done between April 17, 2011, and Nov 1, 2015. 268 896 participants were present at the time of the first dose, with 188 206 in the intervention group and 80 690 in the control group. OCV coverage of the two groups receiving OCV was 66% (123 659 of 187 214 participants). During 4 years of follow-up, 441 first episodes of severe cholera were detected (243 episodes in the vaccinated groups and as 198 episodes in the unvaccinated group). Overall OCV protection was 36% (95% CI 19 to 49%) and total OCV protection was 46% (95% CI 32 to 58). Cumulative total vaccine protection was notably lower for people vaccinated before the age of 5 years (24%; -30 to 56) than for people vaccinated at age 5 years or older (49%; 35 to 60), although the differences in protection for the two age groups were not significant (p=0·3308). Total vaccine protection dropped notably (p=0·0115) after 3 years in children vaccinated at 1-4 years of age.InterpretationThese findings provide further evidence of long-term effectiveness of killed whole-cell OCV, and therefore further support for the use of killed whole-cell OCVs to control endemic cholera, but indicate that protection is shorter-lived in children vaccinated before the age of 5 years than in people vaccinated at the age of 5 years or older.FundingBill & Melinda Gates Foundation.TranslationFor the Bengali translation of the abstract see Supplementary Materials section.

Project description:Cholera is both an endemic and epidemic disease in many low and middle-income countries (LMICs). Strategies for cholera control include improving water, sanitation, and hygiene; providing early and effective treatment; and deploying oral cholera vaccine (OCV). This last strategy is relatively new, and countries considering its introduction are interested in knowing the potential cost not only of the vaccine, but also the cost of introduction. This paper describes the costing of OCV introduction in LMICs using a publicly available Excel-based tool known as the CholTool. It includes estimates of delivery cost categories which cover not only the service delivery costs (e.g. vaccine procurement, handling, storage, and transport; vaccination administration, monitoring supervision, and field support), but also the programmatic costs associated with introducing a new vaccine (i.e. microplanning, communication and training materials development, sensitization/social mobilization, and personnel training) to ensure that a comprehensive estimate is provided with health payer perspective. CholTool takes the user through a structured sequence of interlinked modules containing input parameter cells (assumptions), decision cells (variable selections), and formulas (calculations) to produce customized cost estimates based on standardized methods. The tool provides both financial and economic cost estimates, to ensure that both costs are available for consideration. Four examples of applications of CholTool are presented in three countries- one in Ethiopia, two in Malawi and one in Nepal. The estimates of economic delivery cost per dose (including service delivery and programmatic costs) were (in USD 2016): $2.89 in Ethiopia, $3.04 in Malawi1, $3.35 in Malawi2 and $3.06 in Nepal. A cost projection conducted before the campaign using the tool and a retrospective costing using the tool in Nepal resulted in no significant difference between economic delivery costs per dose.

Project description:BackgroundHuman papillomavirus-related oropharyngeal cancer (HPV-OPC) incidence is increasing, but the natural history of the precursor-oral HPV-has not been well described.MethodsThis observational cohort study of people living with HIV and at-risk HIV uninfected people evaluated participants semiannually using 30-second oral rinse and gargle specimens over 7 years. Initially, 447 participants were followed for 4 years as part of the Persistent Oral Papillomavirus Study, and a subset of 128 who showed persistent infections at the last Persistent Oral Papillomavirus Study visit had an additional visit, as part of the Men and Women Understanding Throat HPV Study, on average 2.5 years later. Extracted DNA from oral rinse and gargle specimens was amplified using polymerase chain reaction and type specification of 13 oncogenic HPV types. Risk factors for oncogenic oral HPV clearance were evaluated using Cox models.ResultsThe majority of oncogenic oral HPV infections cleared quickly, with a median time to clearance of 1.4 years (interquartile range = 0.5-3.9 years). After 7 years of follow-up, 97% of incident and 71% of prevalent infections had cleared. Lower HPV-16 viral load was statistically significantly associated with clearance (per 10-fold decrease in copy number: adjusted hazard ratio [aHR] = 2.51, 95% confidence interval [CI] = 1.20 to 5.26; P = .01). Adjusted analyses showed that oncogenic oral HPV clearance was lower among prevalent than incident-detected infections (aHR = 0.44, 95% CI = 0.35 to 0.55), among men than women (aHR = 0.74, 95% CI = 0.60 to 0.91), for older participants (aHR per 10 years increasing age = 0.81, 95% CI = 0.74 to 0.89), and among people living with HIV (aHR = 0.76, 95% CI = 0.60 to 0.95). One participant who had oral HPV-16 consistently detected at 10 study visits over 4.5 years was subsequently diagnosed with HPV-OPC.ConclusionsThis prospective study of oncogenic oral HPV infection is the longest and largest quantification of oral HPV-16 infections to date.

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Efficacy of a low-cost, inactivated whole-cell oral cholera vaccine: results from 3 years of follow-up of a randomized, controlled trial.

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Efficacy of a low-cost, inactivated whole-cell oral cholera vaccine: results from 3 years of follow-up of a randomized, controlled trial.

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