Effect of vaccination with phase I and phase II Coxiella burnetii vaccines in pregnant goats

Livestock is considered to be the major “source” of human Q fever. The efficacy of two currently available vaccines (Coxevac, phase I, CEVA Santé Animale and Chlamyvax FQ, phase II, MERIAL) against Coxiella excretion was investigated in terms of risks to human health. Two months before mating, 17 goats were vaccinated subcutaneously against Coxiella burnetii with an inactivated phase I vaccine and 16 goats were vaccinated with an inactivated phase II Coxiella mixed with Chlamydophila abortus vaccine. Fourteen goats were left unvaccinated. At 84 days of gestation, the goats were subcutaneously challenged with 104 bacteria of C. burnetii strain CbC1. Phase I vaccine was effective and dramatically reduced both abortion and excretion of bacteria in the milk, vaginal mucus and feces. In contrast, the phase II vaccine did not affect the course of the disease or excretion.