Knobel et al. (2017) recently published an article based on their South African study in which they suggest that the rabies vaccine can protect against all-cause mortality due to its effect against diseases other than rabies.
They concluded that the existence of a strong non-specific protective effect of rabies vaccine on the mortality in dogs could have implications on the design of dog rabies control programmes that aim to eliminate dog-mediated human rabies cases (Knobel et al. 2017).
Additionally, reduced mortality in vaccinated subgroups following mass vaccination campaigns in dogs will have the beneficial effect of extending the period during which population immunity remains above the critical threshold needed to prevent outbreaks of rabies (Knobel et al. 2017).
Knobel, D.L. et al. (2017). Rabies vaccine is associated with a decrease in all causes of mortality in dogs. Vaccine, 35, 3844-3849 doi: 10.1016/j.vaccine.2017.05.095.