Vaccine prophylaxis of abattoir-associated Q fever.

Q fever is an important cause of morbidity in Australian meatworkers; recently there have been sharp outbreaks of Q fever in abattoirs in several states. In an attempt to control Q fever by vaccination, 924 nonimmune volunteers at two South Australian abattoirs were inoculated with one dose of a purified, formalin-inactivated, Coxiella burneti, Henzerling strain, phase 1 vaccine. Some 56% of workers in one abattoir, and 64% in the other, seroconverted after vaccination. In the 18 months after vaccination, no Q fever occurred in fully vaccinated subjects, whereas there were 34 cases in 1349 unvaccinated workers. Transient local reactions were noted in most vaccinated subjects; only a few had mild general reactions. No cases of vaccine-enhanced disease were observed. Vaccination of susceptible individuals with a purified C burneti phase 1 vaccine appears to be safe and effective in preventing Q fever in the abattoir.