Laurel Gershwin, DVM, PhD, DACVM, of the University of California-Davis, told CVC San Diego attendees today that veterinarians can be confident in their core vaccines: all those created for dogs and cats by major veterinary companies induce an immune response that lasts well beyond three years—even if the vaccine is labeled as a one-year vaccine.
This duration of immunity is demonstrated by antibody titer testing, which verifies the presence of antibodies targeted to a particular disease agent in the animal’s system. However, in addition to antibodies, animals are also protected by a cell-mediated immune response, in which memory T cells attack the virus through cytotoxic activity, Gershwin says.
“Even though a titer may not come back from the lab as positive, that does not necessarily mean the dog is susceptible to infection,” Gershwin says. “This is because there are long-lived memory B and T cells that can provide protection in previously vaccinated animals. ... The memory B and T cell response can be vigorous despite the absence of antibodies.”
One CVC attendee specifically asked whether even core vaccines labeled for one year of immunity would provide longer-lasting protection, and Gershwin verified that they would. “The only difference between those that have the three-year label and those that don’t is that some have conducted the research and others haven’t,” she told the veterinarians in the room. “Among reputable manufacturers, all core vaccines for dogs and cats will provide well over a three-year response.”
Representatives from vaccine manufacturers Merck and Merial attended Gershwin’s session and stated that their companies supported three-year duration of immunity even for their one-year core vaccine products. If an animal given a one-year vaccine develops a break in immunity within three years, the manufacturer will provide financial and technical assistance for that patient and pet owner, they said.