In patients with AIDS, which vaccine is contraindicated?

In patients with AIDS, the varicella vaccine is contraindicated due to its live attenuated virus formulation. Individuals with compromised immune systems, such as those with AIDS, may not mount an adequate immune response to the vaccine and are also at risk for serious complications from the vaccine itself. The live virus can potentially cause disease in these patients, making it unsafe for them.

In contrast, other vaccines mentioned may be appropriate depending on the individual's immune status. For example, the MMR (measles, mumps, rubella) vaccine can be given to those with mild immunosuppression after a careful assessment, while flu vaccines, particularly inactivated ones, are generally recommended for immunocompromised patients. Vivotif is an oral typhoid vaccine which is also contraindicated in those with moderate to severe immunosuppression, but the primary concern with live virus vaccines like varicella makes it the most critical vaccine to avoid in patients with AIDS.