This paper reviews current scientific information about the duration of imm
unity induced in dogs by infection or vaccination. it describes the shortco
mings of the methods used to measure the immune responses of dogs, and expl
ains the need for basic studies on the nature of protective humoral and cel
lular responses, and standardised assays for the long-term duration of immu
nity to pathogens other than rabies. The information is inadequate to warra
nt uniform recommendations on the ideal intervals for vaccination; each vac
cine must be evaluated on the basis of its own merits and the characteristi
cs of the disease it is intended to guard against.