In very rare occasions, cats can develop sarcoma at the injection site, yet skipping vaccines is far riskier. A veterinary oncologist explained that while this condition has been observed, its occurrence is extremely uncommon, roughly three cases per hundred thousand vaccinations. Dogs can have certain papillomaviruses that elevate the risk of specific cancers, such as squamous cell skin cancer. The virus can be transmitted to a puppy from the mother and through saliva when dogs share bowls or toys. Humans also host papillomaviruses, including some oncogenic types, but transmission between dogs and people is not possible because these infections are species-specific.
The veterinarian added that to mitigate the risk of sarcoma, some vaccines are recommended to be given not on the shoulders but at the crease of the knee or near the base of the tail, locations that are easier to treat if issues arise. The immune system’s role includes defending against cancer, and a weakened immunity from viral infections in an unvaccinated animal can raise cancer risk, so vaccination should not be avoided.
For more information on cancer prevention in dogs, see the material on cancer prevention in dogs [citation: socialbites.ca].