Kittens are given a set of vaccines known as the “core vaccines” in their first year of age which enables them to combat different infectious diseases that can cause high mortality rates. In previous studies, it has been assumed that yearly boosters are necessary for kittens vaccinated at one-year of age to reinforce the protective effect of the vaccine. However, recent findings reveal that not all vaccines require annual boosters to exert a maximal protective effect. Further investigation is still needed to prove that administering booster shots are beneficial for cats. A laboratory or serological test that measures the number of antibody titers can often be performed by veterinarians to assess if the cat has developed a good immune response that can adequately protect them against diseases and to determine if there is a need for additional boosters. However, these antibody titer tests may not be too ideal since they will cost more than the booster shot and can be a stressful experience for cats. However, high antibody titers do not necessarily confer definite protection from disease strains with high virulence.