Why is Bordatella given twice a year instead of annually?

Research shows that Bordetella protection lasts only 90 to 120 days, requiring 3 to 4 boosters annually for continual protection. For convenience, most pet owners get the Bordetella protection only twice annually. Many dogs get the protection more frequently if they frequently come in contact with other dogs such as at groom shops, city parks, boarding kennels, etc. Lymes disease, spread by ticks and becoming more prevalent every year in our area making annual immunization an important protection.