Feasibility of a mass vaccination campaign using a two-dose oral cholera vaccine in an urban cholera-endemic setting in Mozambique

doi:10.1016/j.vaccine.2005.10.006

Vaccine

Volume 24, Issue 22, 29 May 2006, Pages 4890-4895

https://doi.org/10.1016/j.vaccine.2005.10.006 Get rights and content

Abstract

We conducted a study to assess the feasibility and the potential vaccine coverage of a mass vaccination campaign using a two-dose oral cholera vaccine in an urban endemic neighbourhood of Beira, Mozambique. The campaign was conducted from December 2003 to January 2004. Overall 98,152 doses were administered, and vaccine coverage of the target population was 58.6% and 53.6% for the first and second rounds, respectively. The direct cost of the campaign, which excludes the price of the vaccine, amounted to slightly over $90,000, resulting in the cost per fully vaccinated person of $2.09, which is relatively high. However, in endemic settings where outbreaks are likely to occur, integrating cholera vaccination into the routine activities of the public health system could reduce such costs.

Introduction

Considerable progress has been made during the last two decades in the development of new-generation oral vaccines against cholera [1]. These are licensed in many countries and used mainly by travellers from industrialized countries visiting endemic areas. Oral cholera vaccination may complement usually recommended control measures in areas with high endemicity. However, a recent WHO meeting of experts recommended that demonstration projects be first undertaken [2]. Indeed, demonstration projects using oral cholera vaccines are essential to determine whether and under which circumstances cholera vaccination may help countries in their fight against the disease. Although Sub-Saharan African countries account for a significant proportion of the cholera cases reported worldwide [1]. Feasibility and cost of a mass oral cholera vaccination campaign have not been explored in the region, apart from a study undertaken in a refugee setting in Uganda [3]. Such information will be crucial for informed decision-making, by governments of cholera-affected countries and international organizations regarding the utilization of vaccination for cholera control.

Mozambique experienced major epidemics occurring successively from 1997 onwards, and cholera control activities typically focus on case management, water chlorination campaigns, and dissemination of hygiene messages. With improved case management, case fatality ratio have decreased to below 1%, but remain high in the most severely affected or isolated areas [4]. In addition, response to cholera outbreaks is expensive and disrupt other essential health care activities. Orally administered cholera vaccines represent a potential new tool to prevent or control cholera outbreaks. The two-dose oral killed rBS-WC vaccine is well tolerated and provides significant protection against cholera. Field trials conducted in Bangladesh [5], [6] and in Peru [7], showed that this vaccine confers a high level of protection: 85% after the second dose and still about 62% protection two years later, in adult vaccinees. Protection among children less than 5 years is high during the first 6 months and then decreases dramatically.

A demonstration project, using the two-dose killed oral cholera vaccine was conducted in Beira, Mozambique. The objectives were: (i) to evaluate the requirements for the organization of a mass vaccination campaign within an urban African setting, the technical difficulties encountered in the administration of the vaccine and the costs incurred; (ii) to assess the results of this campaign, in terms of acceptability and vaccine coverage; and (iii) to assess the effectiveness of the vaccination. This paper reports on the feasibility, the acceptability and vaccine coverage only. The results on vaccine effectiveness are reported elsewhere [8].

Section snippets

Study site and population

The port city of Beira, in the Sofala province, is the second largest city in Mozambique (Fig. 1). Beira was built on swampy ground at the mouth of the Pungwe River and has a population of approximately 450,000, divided into 22 neighbourhoods (bairros). Many areas of Beira are located below sea level. Cholera is endemic in Beira with high seasonal variations. Cases usually occur during the rainy season from January to June. The characteristic marshy areas with brackish water, periodic flooding

Feasibility of the mass vaccination campaign

A total of 115,600 doses of rBS-WC vaccine and the corresponding buffer sachets were packed together resulting in a total volume of 9 m³ and weight of 3310 kg. The vaccine was transported in EPI cool-boxes by air from Stockholm, Sweden to Beira via Nairobi, Kenya. In Beira, vaccines and buffer were stored between 4 and 8 °C in a cold room facility. EPI cool-boxes were used for daily transportation of the vaccine to the vaccination sites.

The two rounds of vaccination were conducted prior to the

Discussion

This was the first demonstration project aimed at gaining evidence on the use of oral cholera vaccines in an endemic setting in Africa. Mass vaccination using the two-dose oral killed cholera vaccine proved to be feasible in this highly cholera-endemic urban area in Mozambique which required considerable logistical support and thorough planning and preparation. However, the size of the target population (approximately 20,000), was far short of the actual target of a real campaign aimed at

Acknowledgements

The Diseases of the Most Impoverished (DOMI) Program, funded by the Bill and Melinda Gates Foundation, provided partial support for this study. We would like to thank SBL Vaccine AB, Sweden for generously providing the cholera vaccine free of charge, which allowed us to conduct this project. We are grateful to Mr. Felicio Zacarias (Governor of the Sofala Province) as well as to the staff of the Direccao Provincial de Saude da Sofala (DPSS), of the Direccao de Saude da Cidade and of the Centro

References (14)

J.D. Clemens et al.
Field trials of cholera vaccines in Bangladesh: results from a three year follow-up
Lancet
(1990)
J.L. Sanchez et al.
Protective efficacy of the oral whole cell/recombinant B subunit cholera vaccine in Peruvian military recruits
Lancet
(1994)
D.A. Sack et al.
Cholera
Lancet
(2004)
WHO Cholera
Week Epidemiol Record
(2004)
Global Task Force on Cholera Control. Cholera vaccines: a new public health tool? Report of a WHO meeting. Geneva:...
D. Legros et al.
Mass vaccination with a two dose oral cholera vaccine in a refugee camps
Bull World Health Org
(1999)
Global Task Force on Cholera Control: Report on Cholera Control Programme in Mozambique. Geneva: World Health...

There are more references available in the full text version of this article.

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Cost of oral cholera vaccine delivery in a mass immunization program for children in urban Bangladesh
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Cholera poses a substantial health burden in the developing world due to both epidemic and endemic diseases. The World Health Organization recommends oral cholera vaccines for mass vaccination campaigns in addition to traditional prevention practices and treatments in resource-poor settings. In many developing countries like Bangladesh, the major challenge behind implementing mass vaccination campaigns concerns the affordability of the oral cholera vaccine (OCV). Vaccination of children with OCV is not only an impactful approach for controlling cholera at the population level and reducing childhood morbidity but is also considered more cost-effective than vaccinating all ages. The aim of the study was to estimate the cost of an OCV campaign for children from a societal perspective using empirical study. A total of 66,311 children aged 1 to 14 years old were fully vaccinated with two doses of the OCV Shanchol while 9,035 individuals received one dose of this vaccine. The estimated societal cost per individual for full vaccination was US$ 6.11, which includes the cost of vaccine delivery estimated at US$ 1.95. The cost per single dose was estimated at US$ 2.86. The total provider cost for full vaccination was estimated at US$ 6.01 and the recipient cost at US$ 0.10. Our estimation of OCV delivery costs for children was relatively higher than what was found in a similar mass OCV campaign for all age groups, indicating that there may be additional cost factors to consider in targeted vaccine campaigns. This analysis provides useful benchmarks for the possible costs related to delivery of OCV to children and future OCV cost-effectiveness models should factor in these possible cost disparities. Attempts to reduce the cost per dose are likely to have a greater impact on the cost of similar vaccination campaigns in many resource-poor settings.
Evaluation of a prototype decontamination mobile unit (UMDEO) for COVID-19 vaccination: A cross-sectional survey in France
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This was a descriptive cross-sectional study conducted in Toulouse over two days. UMDEO is a fully comprehensive, versatile solution that was deployed as a 5-row vaccination unit. A written questionnaire was distributed from March 6th-7th, 2021 among all patients presenting for vaccination at the mobile center, as well as the team participating in the vaccination campaign.
Among the vaccinated patients (n = 1659), 1409 participants (84.9%) filled out the survey, as well as 68 out of 85 (80%) within the UMDEO team. The maximum patient rate was 98 people per hour. The majority of participants and caregivers (1307 [93.2%] and 67 [98.5%] respectively) agreed that the mobile unit increased access to vaccination. A total of 91.3% patients (n = 1281) and 95.6% caregivers (n = 65) believed that it would speed up the overall vaccination campaign.
The majority of the vaccinated population and of the team participating in the survey were satisfied with the usefulness of UMDEO as a vaccination center. Toulouse is currently the only city to have used such a structure for vaccination, but it could be used as a basis for planning other mobile units to increase vaccination access.
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Costs are presented as per-dose estimates, and for routine fixed-site and outreach delivery, costs are also aggregated at the facility level for two facility types: low-volume and high-volume facilities. Country delivery cost data were extracted from studies published in the Immunization Delivery Cost Catalogue (IDCC) [19]: ten campaign studies [20–29], 12 studies of new and underutilized vaccine introductions [23,30–40], and primary data from two routine outreach studies [41,42]. Data on service delivery logistics and the coverage levels achieved were extracted from the original studies and publications, and used to model potential changes in the cost of delivering immunization services on a per-dose or per-facility basis.
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We found that implementing a range of measures to protect health workers and communities from COVID-19 transmission could result in a per-facility start-up cost of $466–799 for routine fixed-site delivery and $12–220 for routine outreach delivery, and $12–108 per immunization campaign site. A recurrent monthly cost of $137–1,024 for fixed-site delivery and $152–848 for outreach delivery per facility could be incurred, and a $0.32–0.85 increase in the cost per dose during campaigns.
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Average vaccinator training costs to reach hard-to-reach populations who were targeted through outreach were $0.04 per dose, compared to $0.02 per dose for populations that lived near health facilities (incremental cost of $0.02) [35]. We identified 29 studies that included 36 cost estimates associated with vaccinators being willing and available to administer vaccines (Table 2) [31,32,35,37,39,41,42,45–47,49–67]. These costs consisted of labor and personnel costs, such as salaries and per diems, as well as the costs of incentives.
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^☆: This work was supported by Médecins Sans Frontières, the Bill and Melinda Gates Foundation through the Diseases of Most Impoverished Program administered by the International Vaccine Institute, Korea, the Government of Mozambique, and the World Health Organization. SBL Vaccine AB, Sweden, donated the vaccines.

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Feasibility of a mass vaccination campaign using a two-dose oral cholera vaccine in an urban cholera-endemic setting in Mozambique☆

Abstract

Introduction

Section snippets

Study site and population

Feasibility of the mass vaccination campaign

Discussion

Acknowledgements

Lancet

Lancet

Lancet

Week Epidemiol Record

Mass vaccination with a two dose oral cholera vaccine in a refugee camps

Bull World Health Org