Systematic review and meta-analysis of effectiveness of viral vaccines for mitigation of bovine respiratory disease complex

Viral vaccines are commonly used to reduce risk from bovine respiratory disease (BRD) in feedlot cattle upon arrival. The purpose of this study was to systematically review available literature on the effectiveness of viral antigen vaccines to reduce the morbidity and mortality associated with BRD. A systematic review identified 31 studies consisting of 88 trials evaluating viral vaccines in either an experimental challenge model or naturally occurring disease model. Studies were categorized based on exposure (natural or experimental) and viral component (bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus (BVD), bovine respiratory syncytial virus (BRSV), parainfluenza type 3 virus (PI3), or combinations). A meta-analysis was performed to evaluate the risk ratios expected compared to control (or cattle not receiving vaccinations).

Natural exposure trials evaluating commercially available viral combination (BHV-1, BVDV, BRSV, and PI3) vaccines illustrated reduced risk of BRD morbidity and mortality compared to control cattle. The combination vaccines had a relative morbidity risk of 0.44 (95% confidence interval: 0.26 – 0.74) and mortality risk of 0.19 (95% confidence interval: 0.06 – 0.67) relative to non-vaccinated cattle. In disease challenge experimental models single antigen vaccines for BHV-1 and BVD revealed lower BRD morbidity risk compared to control calves. While this work does not provide definitive evidence for which viral vaccine components are necessary for reducing risk of BRD, the results illustrate that vaccination with viral vaccines can be a valuable tool in mitigating BRD risk.

M.E. Theurer, R.L. Larson, B.J. White. Systematic review and meta-analysis of the effectiveness of commercially available vaccines against bovine herpes virus, bovine viral diarrhea virus, bovine respiratory syncytial virus, and parainfluenza-type 3 virus for mitigation of bovine respiratory disease complex in cattle. J Am Vet Med Assoc. 2015 246:126-142.