A critical review and meta-analysis of the efficacy of whole-cell killed Tritrichomonas foetus vaccines in beef cattle.

This review assesses the efficacy of whole cell Tritrichomonas foetus vaccine to prevent and treat trichomoniasis in beef cattle. Three databases were searched in June 2012. Eligible studies compared infection risk, open risk, and abortion risk in heifers or infection risk in bulls that received vaccine compared with no vaccine. Study results were extracted, summary effect measures were calculated, and the quality of the evidence was assessed. From 334 citations identified, 10 were relevant to the review. For heifers, there was limited evidence of moderate quality to assess the impact of vaccination on infection risk (RR, 0.89; P = .16; 95% CI, 0.76-1.05; 6 randomized and 4 nonrandomized studies; 251 animals) and open risk (RR, 0.80; P = .06; 95% CI, 0.63-1.01; 6 randomized and 5 nonrandomized studies; 570 animals). The quality of the body of work describing the impact of vaccination on abortion risk was low (summary RR, 0.57; P = .0003; 95% CI, 0.42-0.78; 3 randomized and 2 nonrandomized studies; 176 animals). The quality of evidence was very low for duration of infection (mean difference, -23.42; P = .003; 95% CI, -38.36 to -7.85; 2 randomized and 3 nonrandomized studies; 163 animals). Although the summary effect measures suggest a benefit to vaccination, due to publication bias the effect reported here is likely an over estimate of efficacy. For bull-associated outcomes, the evidence base was low or very low quality.