What Is Vaccination?
Vaccination is the process of introducing an antigen (a killed, modified-live, or recombinant pathogen) into an animal's body to stimulate an immune response and create protective memory. Vaccines do not cure disease — they train the immune system to recognise and fight a specific pathogen rapidly if exposure occurs later, before the disease can take hold.
Understanding Vaccination
Vaccines are categorised as core (recommended for all pets regardless of lifestyle) and non-core (recommended based on individual risk and exposure). For dogs, core vaccines include DHPP (distemper, hepatitis, parvovirus, parainfluenza) and rabies. For cats, core vaccines include FVRCP (feline viral rhinotracheitis, calicivirus, panleukopenia) and rabies. Non-core vaccines include leptospirosis, Bordetella, and canine influenza for dogs; FeLV for cats at risk of outdoor exposure.
The puppy and kitten series of vaccinations exists because maternal antibodies passed from the mother to offspring interfere with vaccine effectiveness early in life — they neutralise the vaccine antigen before the immune system can build its own response. Multiple boosters at 3–4 week intervals are given until the maternal antibody levels fall sufficiently for the vaccine to work. The series is not complete until the final booster is given, typically around 16 weeks of age.
Adult vaccination schedules vary by vaccine and jurisdiction. Some vaccines (notably parvovirus and distemper) now have strong evidence supporting 3-year or longer intervals after the initial series in adults, rather than annual boosters. Rabies schedules are legally mandated and vary by location. Titer testing — measuring antibody levels — is increasingly accepted as an alternative to automatic re-vaccination for some core vaccines in pets with documented immunity.