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Challenges to effective chicken vaccination: uptake, completeness and timeliness of schedules among commercial layer farms in Tanzania

Year: 2026

Type: article

Abstract: Infectious diseases are a major cause of high chicken morbidity and mortality rates, and subsequent use of antimicrobials thereby fostering the development of antimicrobial resistance. While vaccination is a key preventive measure which subsequently reduces reliance on antimicrobials, its implementation in low-income countries is often hindered by socioeconomic and farming challenges. This cross-sectional study evaluated vaccination uptake, completeness, timeliness and farmers' knowledge, attitudes, and practices across 200 commercial layer chicken farms in Dar es Salaam, Morogoro, and Unguja from March to June 2023. Data analysis included ANOVA, t -tests, and multivariable logistic regression. The study revealed mean scores of 55.20% for vaccination knowledge, 81.65% for attitudes on vaccination, and 55.10% for practices related to vaccination among the farmers assessed. Vaccination uptake ranged from 1 to 9 vaccines (median: 3). While 74% of farms vaccinated against the three nationally recommended core diseases (Newcastle disease, infectious bursal disease, and fowl pox), only 5% vaccinated against bacterial diseases. Compliance was suboptimal, with 47.50% of farms having incomplete schedules and 93% reporting at least one untimely vaccination. Multivariable logistic regression identified several risk factors. Farmers in Unguja, small-scale producers, and younger farmers were significantly more likely to have incomplete schedules. Untimely vaccination was higher in deep-litter systems compared to battery cages. Furthermore, limited awareness of vaccine availability increased the odds of untimely vaccination sevenfold. These findings suggest that implementation of targeted interventions that account for farmer-level factors associated with vaccination and evidence-based policies are essential for improving chicken vaccination programs. This is necessary to enhance chicken health, productivity, and antimicrobial resistance control in commercial layer chicken farms.

Source: Vaccine X

DOI: 10.1016/j.jvacx.2026.100868