Adoption of Newcastle disease vaccines by smallholder households in Tanzania

Abstract

Veterinary vaccines contribute to the maintenance of animal health, control of animal diseases, and improvement of the socioeconomic well-being of people living in low and middle-income countries who rely on livestock as a source of livelihood; however, benefits cannot be realized unless vaccines are used. Newcastle disease (ND) vaccines enhance smallholder chicken production but uptake by chicken-owning households in Tanzania is estimated at only 22% by the 2012 National Census of Agriculture. We examined low uptake from the household perspective with the goal of informing strategies to increase vaccine coverage. An interdisciplinary, mixed methods approach incorporated a cross-sectional survey of 535 households across three regions to identify determinants and barriers to vaccine adoption, double-bounded contingent valuation to assess willingness to pay for vaccines, and focus groups to identify preferences between two vaccines types. Eighty percent of households were aware of ND vaccines, 57% had previously vaccinated, and 26% had recently vaccinated. The average flock size was thirteen chickens. Knowing someone who vaccinates and owning more chickens increased the likelihood of previous and recent vaccination. A consistently high willingness to pay for vaccines indicated ND vaccines are valued and preferred. While income was not a determinant of vaccination, households with some on-farm income in the previous month had higher willingness to pay, suggesting vaccines are accessible to agriculture-dependent households with various levels of income. I-2 vaccine is considered superior by experts because of its thermotolerance, but has not replaced the non-thermotolerant La Sota vaccine among smallholders. Chicken owners perceived both vaccines to be effective and based preferences more on administration style and ease of sharing than thermotolerance, thereby contributing to the co-existence of the two vaccines in the market. Vaccines were shared by 61% of vaccinating households, a strategy that reduces individual household costs. These findings confirm that ND vaccines are effective for small flocks in village settings and suggest barriers to access are further upstream in the vaccine supply chain. Strategies that may increase vaccination are scaling up flock sizes and allowing the supply chain to provide access to both La Sota and I-2 vaccines.