The impact and cost-effectiveness of controlling cholera through the use of oral cholera vaccines in urban Bangladesh: A disease modeling and economic analysis

Abstract

BackgroundCholera remains an important public health problem in major cities in Bangladesh, especially in slum areas. In response to growing interest among local policymakers to control this disease, this study estimated the impact and cost-effectiveness of preventive cholera vaccination over a ten-year period in a high-risk slum population in Dhaka to inform decisions about the use of oral cholera vaccines as a key tool in reducing cholera risk in such populations.Methodology/Principal findingsAssuming use of a two-dose killed whole-cell oral cholera vaccine to be produced locally, the number of cholera cases and deaths averted was estimated for three target group options (1–4 year olds, 1–14 year olds, and all persons 1+), using cholera incidence data from Dhaka, estimates of vaccination coverage rates from the literature, and a dynamic model of cholera transmission based on data from Matlab, which incorporates herd effects. Local estimates of vaccination costs minus savings in treatment costs, were used to obtain incremental cost-effectiveness ratios for one- and ten-dose vial sizes. Vaccinating 1–14 year olds every three years, combined with annual routine vaccination of children, would be the most cost-effective strategy, reducing incidence in this population by 45% (assuming 10% annual migration), and costing was $823 (2015 USD) for single dose vials and $591 (2015 USD) for ten-dose vials per disability-adjusted life year (DALY) averted. Vaccinating all ages one year and above would reduce incidence by >90%, but would be 50% less cost-effective ($894–1,234/DALY averted). Limiting vaccination to 1–4 year olds would be the least cost-effective strategy (preventing only 7% of cases and costing $1,276-$1,731/DALY averted), due to the limited herd effects of vaccinating this small population and the lower vaccine efficacy in this age group.Conclusions/SignificanceProviding cholera vaccine to slum populations in Dhaka through periodic vaccination campaigns would significantly reduce cholera incidence and inequities, and be especially cost-effective if all 1–14 year olds are targeted.

Evaluating the costs of cholera illness and cost-effectiveness of a single dose oral vaccination campaign in Lusaka, Zambia

“…The costs per case averted during the 2016 OCV campaign were higher and estimated at US$369–US$532 for children ≤15 years old as compared to US$352–US$528 for older patients. This was similar to findings documented by Khan et al, 2018 that showed that varying costs of treatment do not substantially change the resulting ICERs [50].…”

“…Based on prescribed guidelines for treating cholera patients of different age groups, this paper considers treatment costs and vaccine effectiveness as key variables for calculating ICERs. Other studies have disregarded vaccine efficacy and demonstrated cost-effectiveness of OCV in endemic settings using cholera incidence and cost of vaccine as key variables [50].…”

“…Assuming 50% vaccine coverage among individuals aged ≥2years, a reactive vaccination campaign in Zimbabwe could have averted 1,320 deaths and 23,650 Disability Life Adjusted Years (DALYs) in 2008–2009 [23]. Cholera vaccinations among 1–14 year olds every three years would be the most cost-effective, reducing incidence by 45% and costing US$823 for single dose vials per DALY averted as compared to more than 90% reduction in incidence for older persons, but less cost-effective at US$894–US$1,234 per DALY [24].…”

Combating Cholera

“…Azithromycin is recommended for pregnant women and young children whereas tetracycline is suitable for adults. They are both more advantageous than ciprofloxacin and erythromycin 1, 11, 12 .…”

Willingness to pay for oral cholera vaccines in urban Bangladesh

“…The endemicity of cholera in Bangladesh is demonstrated by the predictable yearly occurrence of the disease in the country's high-risk districts and the repetitive seasonal pattern of cholera outbreaks, in spring or autumn, or both [4]. Indeed, cholera is increasingly becoming an urban disease, in Bangladesh particularly for Dhaka, the capital city of Bangladesh [5]. Dhaka has also experienced massive cholera outbreaks in the past two decades, especially during major floods in 2007 and 2009.…”