After being bitten by a cat and having received the rabies vaccine, if bitten again, is it necessary to get another injection?

Generally speaking, whether a rabies vaccine shot is needed after being bitten by a cat again following previous vaccination depends on the time interval between the incidents. If the interval is short, another injection is usually unnecessary; however, if the interval is long, it is recommended to receive another rabies vaccine. The specific analysis is as follows:

The effective protection period of the rabies vaccine typically lasts from six months to one year. Within this period, antibody levels in the human body remain at sufficient concentrations to defend against reinfection by the rabies virus. If a person is bitten by a cat again before the protective period of the previous vaccination has expired, the antibodies in their body are generally still effective and capable of neutralizing the virus to prevent infection; therefore, re-vaccination is not required.

Over time, antibody levels in the body gradually decline due to metabolic processes. If a significant amount of time has passed since the last rabies vaccination—longer than the vaccine's effective protection period—the concentration of antibodies may no longer be high enough to provide adequate protection. In such cases, if bitten by a cat again, there may be a risk of infection. Therefore, it is advisable to receive another dose of the rabies vaccine to stimulate the body to produce new antibodies and enhance immunity.

To prevent rabies, individuals should avoid contact with animals that have not been vaccinated against rabies, thereby reducing the risk of bites. Maintaining good personal hygiene and promptly treating any wounds are also important measures for preventing rabies.