Efficacy of a live glycoprotein E-negative bovine herpesvirus 1 vaccine incattle in the field

To assess the efficacy of a live glycoprotein E-negative bovine herpesvirus 1 (BHV1) vaccine to reduce transmission of BHV1 in cattle, a randomised, d ouble-blind, placebo-controlled field trial including 84 herds was conducte d in the Netherlands. The incidence of BHV1 infections during 17 months was monitored by detecting antibodies against BHV1 glycoprotein E. In the plac ebo-treated group 214 seroconversions in 3985 paired sera, and in the vacci nated group 67 seroconversions in 3601 paired sera were detected. Based on these data, the transmission ratio R-o was estimated for each treatment. us ing the maximum likelihood approach and the martingale approach. In placebo -treated herds R-o was 3.5 (CI 1.4-3.1) using maximum likelihood and 2.8 (S .E. 0.4) using the martingale approach. In the vaccinated group these estim ations were 1.2 (CI 0.5-1.5) and 1.5 (S.E. 0.4) respectively. The vaccinate d and placebo-treated group differed significantly in transmission of BHV1. These results: suggest that the use of this live gE-negative BHV1 vaccine will reduce the incidence and transmission of BHV1 infections in the held. (C) 2001 Elsevier Science Ltd. All rights reserved.