Field studies evaluating the direct, indirect, total, and overall efficacy of Streptococcus suis autogenous vaccine in nursery pigs.

: Vaccine effectiveness (VE) was evaluated on a farrow-to-finish farm experiencing mortality due to Streptococcus suis. Direct, indirect, total, and overall vaccine effectiveness were analyzed by vaccinating only 75% of pigs in each litter. Cox's regression and logistic regression revealed total and overall VE to be 27% and 21%, respectively.