Recent studies have documented the efficacy of STARTVAC® against S. aureus (Schukken et al. 2014) and E. coli (Bradley et al. 2015). The former study stressed that the economic impact of STARTVAC® in a specific herd depends on the herd’s infection level with S. aureus and management level for udder health, such as milking procedures and culling regime of infected cows. Bradley et al. (2014) reported a return on investment of 2.6:1, but in the article it is stressed that this concerns the effects on milk yield alone and not the effect of the vaccine on the reduced severity of clinical cases