The decision to vaccinate, even with core vaccines, should be based on a risk-benefit assessment for each cat and for each vaccine antigen. Benefits of vaccination should be balanced against the risk of adverse events, likelihood of exposure, and disease severity. Every effort should be made to ensure that cats are healthy before vaccination. However, concurrent illness (including retroviral infections) does not necessarily preclude vaccination.³⁴ The 2020 AAFP Feline Retrovirus Testing and Management Guidelines state that vaccines should not be avoided in cats with retroviral infection because they can develop more severe clinical disease related to FPV and upper respiratory tract infections after natural exposure compared with uninfected cats.³⁴

The Task Force supports the WSAVA’s recommendation that veterinarians should vaccinate every animal with core vaccines and give non-core vaccine.

The vaccination needs of each cat should be evaluated individually and rationally, based on health status, age, and possible, realistic exposure to disease (Table 6). Owners and veterinarians must work together to determine the likelihood of the animal coming into contact with other animals that may spread disease, acquiring parasites that may harbor a disease-causing agent, or living in an area where a disease is known to be endemic or very widespread.²

The life stage of the cat must also be considered with respect to possibility of exposure to disease and the health status of the animal. Infectious diseases are more prevalent in kittens, and in general, kittens (younger than 6 months old) are more susceptible to infection.¹ Younger cats also tend to behave more unpredictably and require more enrichment activities, which may increase their opportunity for exposure.³⁷

The health status of the individual cat, including any previously documented adverse events to vaccines, also determines the vaccination recommendations. The nutritional status, general health (i.e., any concurrent infections or other disease) and the pregnancy status of females may change the type and schedule of vaccination for that individual cat (Table 6). As with lifestyle changes, changes in health status must be evaluated at least yearly.¹

The population density, along with the opportunity for exposure to other cats, is a major factor in determining the need for vaccination. Larger multi-cat households are likely to have a greater risk of infection and disease than households of one or two cats. The introduction of new cats and the social dynamics of the group may also cause immunosuppressive stress, leading to increased risk of disease by new infection or recrudescence. Each cat in a multi-cat environment must have a vaccination plan that balances the protection of the individual with that of the household population.¹

Cats entering boarding, breeding, foster, or shelter situations have increased risk of disease exposure as well as systemic stress. Vaccination may be warranted prior to entering these environments when possible (see Tables 2 and 3). Additionally, vaccination intervals may need to be shortened depending upon these possible scenarios.¹ As with multi-cat households, the vaccination plan for the individual cat must be considered in relation to the entire population.

One vaccination plan or protocol cannot be applied to every cat. Each animal must be evaluated and an individualized plan created that will most protect that particular cat. That plan must be reassessed when changes in health and lifestyle occur, requiring client education and compliance with at least yearly veterinary visits.³⁸