What is the effect of administering immune globulin after receiving the live attenuated varicella vaccine?

Administering immune globulin after receiving the live attenuated varicella vaccine has the effect of inactivating the vaccine. This is because immune globulin contains antibodies that can neutralize the live attenuated virus present in the vaccine. The varicella vaccine works by stimulating the immune system to produce its own antibodies against the varicella-zoster virus, which causes chickenpox. However, when immune globulin is administered shortly after vaccination, it provides ready-made antibodies that interfere with the vaccine's ability to elicit a robust immune response.

This interference can prevent the vaccine from effectively working to build immunity, defeating its purpose. Therefore, the timing of immune globulin administration in relation to live vaccines is crucial, as it can significantly affect the vaccine's effectiveness. In practice, guidelines often recommend delaying the use of immune globulin for certain durations following vaccination to allow the body to mount an adequate immune response.