Vaccinating wild mice against Borrelia burgdorferi—the causative agent in Lyme disease—can lower the prevalence of the spirochete in ticks in a given area, according to a study in PNAS this week, suggesting a means of reducing the rates of infection among humans when no human vaccine is available. While acknowledging that the study was a proof of the concept, some researchers said it had a number of hoops to jump through before it was feasible for widespread use.

Jean I. Tsao and colleagues at the Yale University School of Medicine trapped white-footed mice (Peromyscus leucopus) in a 1400-hectare mixed hardwood forest in southern Connecticut, where Lyme disease is common, and vaccinated them with nonlipidated recombinant fusion protein consisting of outer surface protein (OspA) from B. burgdorferi strain N40. They found that about 55% of all mice had developed resistance to the spirochete by the peak of the...