Practices and trends in last-mile delivery of poultry vaccines in rural areas in developing countries: the case of Newcastle disease vaccine delivery in Bungoma County, Kenya

Newcastle disease (ND) is the single most important infection of village chicken in smallholder farming systems in developing countries. Vaccines for ND control are available but the delivery of safe and potent vaccines in resource-poor settings remains a big challenge due to difficulties in the maintenance of cold chain. This paper reports the results of a study that was carried out in Kenya to assess the storage and handling practices of Newcastle disease vaccines by agro-veterinary shops (agro-shops) during acquisition, storage, and sale to smallholders’ farmers. Data were collected from one hundred and thirty-two agro-shops using semi-structured questionnaires, observation sheets and actual purchase of vaccines over the counter. The results showed that the majority (82 percent) of the agro-shops had a domestic refrigerator that was connected to the electricity grid but many (61 percent) did not have power backup. Sixty percent of them only stocked thermolabile vaccines. Recurrent power outages (62 percent), high cost of electricity (62 percent), and long-distance to vaccine sources (33 percent) were the most common challenges in vaccine storage and sale. Some agro-shops switched refrigerators on and off while others removed vaccines from refrigerators for overnight stay in cool boxes to minimize electricity costs. In some cases, the sale of vaccines was restricted to market days and late afternoon when ambient temperatures were lower to minimize vaccines storage time and vaccine spoilage respectively. Thermostable vaccines were not stored as recommended by the manufacturer and few agro-shops (23 percent) sold reconstituted vaccines. Most shops adequately packaged thermolabile vaccines in improvised materials during sale. Overall, most of the ND vaccine handling and storage practices in the last mile appeared to aim at safeguarding the safety and potency of vaccines, but further research could elucidate the effects of these practices on the quality and potency of ND vaccines.

Africa. The constraints that hinder the adoption of ND vaccines among smallholder 57 chicken producers have been well enumerated in the empirical literature. Among these, 58 vaccine inaccessibility remains existential due to the lack of cost-effective and efficient 59 vaccine delivery systems in many rural areas (7,10,11). With the development and 60 availability of avirulent thermostable ND vaccines that are less sensitive to cold chains, it 61 was anticipated that vaccine accessibility and utilization among smallholder farmers in 62 rural areas would increase. Initial studies conducted in some parts of Africa showed that 63 the vaccine was effective in controlling the ND, thus leading to improvements in chicken 64 production, food security, and women's economic status (12,13). However, a recent study 4 65 in Tanzania showed that the thermostability of ND vaccines was not a major consideration 66 that influenced the purchase decision of the vaccines among smallholder farmers (9). 67 Several interventions aimed at enhancing the accessibility of poultry vaccines among 68 smallholder farmers have been introduced in many parts of sub-Saharan Africa (14-16).

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A major focus of such initiatives has been on the last-mile delivery of vaccines leveraging 70 community-based vaccinators to drive improvements in vaccine coverage. Relatively less 71 attention has been directed at the integrity of vaccines at points of sale, commonly the 72 agro-veterinary shops (hereinafter referred to as agro-shops) that stock and sell vaccines 73 to farmers. These agro-shops some of which are located in small towns in rural areas 74 serve as the end of the cold chain where vaccines are stored before they are sold to 75 farmers. While efforts to increase the accessibility of vaccines to smallholder farmers are 76 important, equally important but often overlooked is the storage and handling of the 77 vaccines in these shops which influences their quality and potency. Agro-shops are a 78 critical node in the vaccine supply chain. Vaccines that reach farmers must be potent and 79 able to offer protection to chickens. Understanding how these agro-shops handle 80 vaccines during acquisition, storage and sale to farmers is therefore important in 81 informing strategies and interventions that are aimed at enhancing the integrity of 82 vaccines thereby contributing to effective control of poultry diseases.

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Veterinary vaccines have to be handled with care from production through distribution 84 and storage until they are applied to target animals (17). This is essential in order to obtain 85 optimal potency of vaccine and maximal results from a vaccination. The maintenance of 86 the cold chain during acquisition, transport and storage by the vaccine handlers has been 87 shown to be critically important (18,19). One of the major challenges in the distribution of 5 88 vaccines in rural areas in developing countries is the limited coverage and reliability of 89 electricity and lack of functional cold chain systems. Ensuring vaccine storage under cold 90 temperatures in these resource-poor settings is not easy because cold chain equipment 91 is often unreliable due to equipment failures, power outages and an unreliable electricity 92 grid (20,21). Moreover, preventive maintenance to avoid equipment failures is rarely 93 executed. Spare parts are often not available and where they are, repair of cold chain 94 equipment can take several months (22-24). As a result, vaccines are often exposed to 95 either heat or freezing, making part of them unusable and resulting in vaccine wastage or 96 impaired vaccine efficacy (25-27).

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The quality of vaccines is one of the important factors in the successful control of poultry 98 diseases which in turn depends on the proper storage and handling of vaccines. If a 99 vaccine is stored outside the recommended temperature for a considerable time, its 100 potency will be adversely affected thereby reducing protection from vaccine-preventable 101 diseases. Available evidence shows that farmers prefer and prioritize ND vaccination 102 programs that have a high capacity to protect birds from mortality (28) and this invariably 103 depends on the quality of the vaccine.

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This paper reports the results of a study that was carried out to assess the vaccine 105 handling practices during the acquisition, storage and sale of Newcastle disease vaccines 106 by agro-veterinary shops in Bungoma County of Kenya. This Newcastle vaccine delivery 107 study was part of a larger study whose objective was to determine how the productivity 108 and market access of indigenous poultry producers in Bungoma County can be improved.         the deeper rural areas may suggest that they could be operating away from the radar of 293 regulators who are by law required to ensure that all veterinary products are stored under 294 the right conditions for quality and safety.

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The risk of vaccine quality deterioration is perhaps greatest in the last mile delivery as 296 vaccines move from agro-shops to farms where they are administered to animals.

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Vaccines are extremely vulnerable to spoilage when they leave refrigerators as they 298 become more exposed to high temperatures and light. Therefore, the way the vaccine  Furthermore, the sale of reconstituted vaccines denies customers their right to product 320 information and increases the risk of malpractices due to lack of product identity.

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Thermostable I-2 ND vaccines were developed to reduce dependence on cold chains.

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The strain I-2 of ND vaccine has many advantages that include thermostability, easy