Pfizer studies duration of serologic response

Orlando, Fla.-Pfizer Animal Health recently unveiled its findings on the duration of serologic response to its Vanguard canine vaccine with or without Leptospira bacterin fraction. And the results may be surprising.

The Pfizer study shows that its Vanguard vaccines demonstrated protection for some dogs up to four years.

Pfizer explains the study was meant to shed light on the issue of duration of immunity, especially considering last year's American Animal Hospital Association canine vaccine protocols calling for three-year vaccination intervals for parvovirus, adenovirus-2, distemper and rabies (depending on state law).

Dr. Ed Kanara, director of Pfizer's technical services, explains, "Pfizer is a science-based company, and we wanted to understand this whole issue of duration of immunity with our vaccines."

The study, which was published in the Journal of the American Veterinary Medical Association's (JAVMA) Jan. 1 issue by Mouzin DE, Lorenzen MJ, Haworth JD, et al, entitled "Duration of serologic response to five viral antigens in dogs," looked at serologic response levels to canine adenovirus-1 (CAV-1), canine adenovirus-2 (CAV-2), canine distemper virus (CDV), canine parvovirus (CPV) and canine parainfluenza virus (CPIV). Kanara adds that the study only focused on Pfizer vaccines.

The study looked at 322 clinically normal dogs from veterinary clinics in the United States and Canada. The dogs were of both sexes, either sexually intact or neutered and at least 2 years of age. Serum samples were tested at Cornell University's Veterinary Diagnostic Laboratory. The company reports that serologic responses were seen in 98.4 percent of dogs for CAV-1, 99 percent for CAV-2, 98.1 percent for CDV, 98.1 percent for CPV and 100 percent CPIV. "Similar response rates were seen for low-risk and high-risk dogs (categorized based on a questionnaire)," the company reports. "Responders to each viral antigen were observed for all time periods, including up to more than four years after the last vaccination."

Inside the results

Kanara says that the data may help practitioners in making vaccination decisions with clients and in setting up appropriate vaccination intervals, however, it is under the discretion of the attending veterinarian.

What to do?

The company says, "Pfizer believes there is no universal protocol. The attending veterinarian continues to be the best person to determine the appropriate protocol for each patient in conjunction with the pet owner."