PORTLAND – Responding to pet owner complaints, state officials have drafted a rule change that would clarify when a dog must receive a rabies vaccination in order to qualify for an annual license.

Many owners have had the misimpression that inoculations must be given every two years, even though vaccine makers and national canine experts recommend three-year intervals.

The current rule says a dog’s last rabies shot must be given within two years of the time of licensing. Conceivably, a dog could be vaccinated every three years, if the owner remembers to renew the license before the two years are up.

For example, if the shot were given Thursday, the owner must renew the license by Aug. 26, 2006, to make it last three years.

If the rule change is adopted, however, licenses will be granted if the owner shows a certificate of immunization is in effect at the time of licensing. That would allow owners to wait three years without having an unlicensed dog.

A public hearing on the rule change will be held Tuesday.

Veterinarians stress the importance of vaccinating against the fatal viral disease because of its continued presence in Maine.