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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.

Cholera is a major global public health problem that causes both epidemic and endemic disease. The World Health Organization recommends oral cholera vaccines as a public health tool in addition to traditional prevention practices and treatments in both epidemic and endemic settings. In many developing countries like Bangladesh, the major issue concerns the affordability of this vaccine. In February 2011, a feasibility study entitled, “Introduction of Cholera Vaccine in Bangladesh (ICVB)”, was conducted for a vaccination campaign using inactivated whole-cell cholera vaccine (Shanchol) in a high risk area of Mirpur, Dhaka. Empirical data obtained from this trial was used to determine the vaccination cost for a fully immunized person from the societal perspective. A total of 123,661 people were fully vaccinated receiving two doses of the vaccine, while 18,178 people received one dose of the same vaccine. The total cost for vaccine delivery was US$ 492,238 giving a total vaccination cost per fully-vaccinated individual of US$ 3.98. The purchase cost of the vaccine accounted for 58% of the overall cost of vaccination. Attempts to reduce the per-dose cost of the vaccine are likely to have a large impact on the cost of similar vaccination campaigns in the future.

•Largest feasibility study to reach high-risk endemic urban population with OCV.•82% were reached with first dose and 87% of those received two doses.•Coverage in children was 81% and it was significantly higher in females than males.•Two doses cost per-person was US$3.93 and delivering cost of single dose was US$0.76.•Mass OCV delivery with existing national immunization system is feasible. A feasibility study of an oral cholera vaccine was carried out to test strategies to reach high-risk populations in urban Mirpur, Dhaka, Bangladesh. The study was cluster randomized, with three arms: vaccine, vaccine plus safe water and hand washing practice, and no intervention. High risk people of age one year and above (except pregnant woman) from the two intervention arms received two doses of the oral cholera vaccine, Shanchol™. Vaccination was conducted between 17th February and 16th April 2011, with a minimum interval of fourteen days between two doses. Interpersonal communication preceded vaccination to raise awareness amongst the target population. The number of vaccine doses used, the population vaccinated, left-out, drop out, vaccine wastage and resources required were documented. Fixed outreach site vaccination strategy was adopted as the mode of vaccine delivery. Additionally, mobile vaccination sites and mop-up activities were carried out to reach the target communities. Of the 172,754 target population, 141,839 (82%) and 123,666 (72%) received complete first and second doses of the vaccine, respectively. Dropout rate from the first to the second dose was 13%. Two complete doses were received by 123,661 participants. Vaccine coverage in children was 81%. Coverage was significantly higher in females than in males (77% vs. 66%, P<0.001). Vaccine wastage for delivering the complete doses was 1.2%. The government provided cold-chain related support at no cost to the project. Costs for two doses of vaccine per-person were US$3.93, of which US$1.63 was spent on delivery. Cost for delivering a single dose was US$0.76. We observed no serious adverse events. Mass vaccination with oral cholera vaccine is feasible for reaching high risk endemic population through the existing national immunization delivery system employed by the government.

Background The global resurgence of cholera, a diarrhoeal disease, has resulted in vaccine demand that exceeds the currently available supply resulting in global calls for next generation cholera vaccines. DuoChol is a novel, thermostable, low-cost oral cholera vaccine capsule currently in development which has the potential to introduce programmatic benefits and efficiencies in cholera vaccination campaigns. Objectives This qualitative study aimed to identify country-specific challenges in handling, distributing, and storing cholera vaccines and to assess the feasibility, acceptability, and policy implications of vaccine capsules compared to current products and practices in vaccination campaigns. Methods Using the World Health Organization’s Vaccine Innovation Framework, consultations were conducted with 81 immunization programme stakeholders from Bangladesh, Ethiopia, Kenya, Mozambique and Tanzania. Results Key barriers to cholera vaccination include challenges in disbursing funds to subnational levels and the need for surged resources, such as additional health workers and cold chain equipment, during campaigns. Stakeholders discussed attributes of the novel vaccine such as improved thermostability and presentation which could reduce or eliminate the existing barriers. Conclusions The stakeholders highlighted that vaccine capsules are desirable for use in the general population as they have the potential to have many advantages over the current practice. However, for children who are not able to swallow the capsule, the currently available liquid oral cholera vaccine may be more desirable. To make an eventual informed decision about whether to recommend use of the vaccine capsule, national stakeholders requested the generation of evidence derived from pilot studies.

Several studies have shown that orally administered killed cholera vaccines are safe and protective in populations at risk of cholera in developing countries. However, these vaccines have not been adopted for use in developing countries because of their expense and limited efficacy in young children. We have tested an inexpensive, killed whole-cell cholera vaccine developed and produced in Vietnam. The efficacy of the vaccine was assessed in a large-scale, open field trial in people at least 1 year old residing in 22 653 households in the central coastal city of Hue. Alternate households were assigned vaccine (67 395 people; two doses per person) or no vaccine (67 058 people). Surveillance for cholera was conducted in all Ministry of Health facilities serving this population. Analysis was by intention to treat. During an outbreak of El Tor cholera 8–10 months after vaccination, 37 cases of cholera requiring inpatient care occurred among age-eligible people allocated to the vaccine group, and 92 cases among age-eligible people allocated to the no-vaccine group (protective impact 60% [95% CI 40–73]). Among the 51 975 people who received the complete two-dose vaccine regimen, the protective efficacy was 66% (46–79); in this subset, the protective efficacy was similar for children aged 1–5 years (68%) and for older people (66%). These findings suggest that oral killed whole-cell vaccines can confer substantial protection against El Tor cholera in young children, who are at highest risk of cholera in endemic settings. An inexpensive, locally produced, and effective oral cholera vaccine may be within reach of the limited health-care budgets of poor countries with endemic cholera, if our findings can be replicated in a randomised double-blind trial.

There is a global need for a cholera vaccine, and two cholera vaccines have been prequalified by the WHO. In this report, initial efficacy data are provided for the use of the Shanchol vaccine during a recent cholera outbreak in Guinea. Large-scale cholera outbreaks have shown the limits of traditional response strategies. 1 The devastating consequences of cholera epidemics in vulnerable populations have opened a debate about ways to improve preparedness and response plans. Two documents, issued by the World Health Organization (WHO) in 2010 and 2011, have also stimulated debate: a revised position paper regarding oral cholera vaccines 2 and the prequalification of the cholera vaccine Shanchol (Shantha Biotech). 3 The two oral cholera vaccines currently prequalified by the WHO are killed whole-cell Vibrio cholerae serogroup O1 vaccines: Shanchol also contains V. cholerae serogroup O139, and Dukoral (Crucell) contains a recombinant cholera toxin . . .

Cholera remains a persistent public health challenge, particularly in resource-limited and conflict-affected settings where inadequate water, sanitation, and hygiene infrastructure exacerbate disease transmission. Sudan has experienced recurrent cholera outbreaks, with two major waves occurring between April 2023 and November 2024, affecting 63,112 individuals and resulting in 1377 fatalities. Given the ongoing armed conflict and humanitarian crisis, traditional cholera prevention measures are often insufficient, necessitating the rapid deployment of Oral Cholera Vaccine (OCV) as a key outbreak response strategy. This study evaluates the administrative coverage, operational performance, and economic efficiency of Sudan's OCV campaigns during this period. A cross-sectional analysis was conducted on Sudan's nationwide OCV campaigns from November 2023 to November 2024. The study assessed vaccination strategies, cold chain resilience, social mobilization efforts, and operational costs per dose. A total of 8,584,190 doses were administered to a target population of 8,654,546, achieving an administrative coverage rate of 99%. Coverage varied across implementation sites. The campaign was conducted under extreme conflict conditions, requiring innovative strategies such as house-to-house vaccination, mobile teams, and integration with novel Oral Polio Vaccine (nOPV) campaigns. Vaccine wastage was minimal (<0.0001 %), and the average operational cost per dose was $0.65. Despite logistical challenges, Sudan reduced the lead time from outbreak confirmation to vaccine request submission to just three days, though vaccine arrival delays of 2–4 weeks remained a bottleneck. Sudan's experience demonstrates the feasibility and cost-effectiveness of OCV campaigns in conflict-affected and resource-limited settings. The high coverage rate, efficient vaccine utilization, and successful adaptation of vaccination strategies highlight the resilience of Sudan's health system in responding to outbreaks amid ongoing conflict and provide critical insights for future cholera control efforts in fragile settings, using partnerships, agile vaccine deployment mechanisms, and innovative implementation approaches.

Following decades of progress, recent years have seen a resurgence of cholera. This has led to unprecedented demand for vaccines from the global emergency stockpile of oral cholera vaccines (OCVs), for outbreak and humanitarian use. As a consequence of chronic supply shortages, preventive vaccination has been suspended since 2022. Although strategic demand scenarios have been published for OCV, models that integrate OCV supply and demand across long time horizons are lacking. Therefore, a quantitative system dynamics model is presented to simulate OCV market dynamics between 2013–2035. The model considers the evolving OCV supply landscape as well as the impact of preventive efforts. Building on stakeholder-driven scenario design, simulations help identify leverage points to improve OCV market health and assess the individual and combined effect of interventions on accelerating cholera control. Specifically, country adoption of preventive vaccination programs and complementary investments in water and sanitation infrastructure are critical to reduce the risk of cholera. Although more resource-intensive, re-vaccination of at-risk populations helps sustain outbreak prevention. It also offers potential benefits such as increasing long-term demand predictability and the overall market size. These serve as important incentives to maintain supplier diversity, thus improving market health. However, since many cholera endemic countries rely on donor support to access OCV, budget constraints associated with reduced development aid can jeopardize programmatic ambitions. Interventions such as the use of rapid diagnostic tests and price competition of procurement can help meet country needs. Finally, market dynamics are influenced by the policies around when to resume preventive OCV use in endemic countries and 2-dose reactive vaccination. Specifically, inventory policies based on the current available stock level versus incoming stock in transit are compared. Aligning OCV supply with demand, both in time and quantity, will be critical to address immediate needs and support broader multi-sectoral activities towards cholera elimination.

Iza Ciglenecki and colleagues from Médecins sans Frontières report their experience of undertaking a mass vaccination campaign with oral cholera vaccines in response to an outbreak in Guinea. Please see later in the article for the Editors' Summary

Improving water and sanitation is the preferred choice for cholera control in the long-term. Nevertheless, vaccination is an available tool that has been shown to be a cost-effective option for cholera prevention in endemic countries or during outbreaks. In 2011 the first low-cost oral cholera vaccine for international use was given prequalification by the World Health Organization (WHO). To increase and prioritize use of the vaccine, WHO created a global stockpile in 2013 from which countries may request oral cholera vaccine for reactive campaigns. WHO has issued specific guidelines for applying for the vaccine, which was previously in short supply (despite prequalification for a second oral vaccine in 2015). The addition of a third WHO-prequalified oral cholera vaccine in 2016 is expected to increase the global stockpile considerably and alleviate supply issues. However, prioritization and best use of the vaccine (e.g. how, when and where to use) will remain challenges. We describe 12 past oral cholera vaccine campaigns, conducted in settings with varying burdens of cholera. These case studies illustrate three key challenges faced in the use of the oral cholera vaccines: regulatory hurdles, cold chain logistics and vaccine coverage and uptake. To pave the way for the introduction of current and future oral cholera vaccines, we discuss operational challenges and make recommendations for future research with respect to each of these challenges.