In a recent article from The Modern Equine Veterinarian, the new leptospirosis vaccine LEPTO EQ INNOVATOR (Zoetis), has received additional approval for use in broodmares for all three trimesters of pregnancy. “Field safety studies, which examined the vaccine when used in the first, second, and third trimesters of pregnancy, showed no systemic or local reactions to vaccinations.” The article goes on to say that one study showed that approximately 13% of bacterial abortions are caused by L. interrogans serovar Pomona, the most common serovar found in horses. “Aborting mares have been reported to shed leptospires in their urine for periods up to three months and can transmit Leptospira to exposed animals.” Prior to launching this vaccine, Zooetis conducted safety and efficacy trials that showed 0% urinary shedding in vaccinated horses that were challenged with L. interrogans serovar Pomona. Additional studies showed that 99.8% of horses vaccinated had no reaction/adverse effects from the vaccine. It is thought, although not demonstrated, that the vaccine may help to reduce the risk of equine recurrent uveitis, abortions or kidney failure that can result from infection by L. interrogans serovar Pomona. The article concludes by stating, “previously unvaccinated healthy mares should receive two doses of LEPTO EQ INNOVATOR approximately three to four weeks apart. Annual revaccination with a single dose is recommended. “
Article: New Indication Granted for Leptospirosis Vaccine. Modern Equine Veterinarian vol. 6, issue 9 2016, p. 17.