Which vaccine is contraindicated in immunocompromised patients, such as those with Crohn's disease on infliximab?

The zoster vaccine, which is designed to prevent shingles caused by the varicella-zoster virus, is contraindicated in immunocompromised patients. This is primarily because this vaccine is a live attenuated vaccine, meaning it contains a weakened form of the virus. In individuals with compromised immune systems, such as those with Crohn's disease who are undergoing treatment with medications like infliximab, there is an elevated risk of adverse reactions because their immune systems may not sufficiently control the live virus.

In contrast, pneumococcal vaccine, tetanus toxoid, and hepatitis A vaccine are generally considered safe for immunocompromised patients. These vaccines are either inactivated or polysaccharide vaccines, which do not pose the same risk as live vaccines. Thus, the zoster vaccine is specifically contraindicated for these patients to prevent potential complications from the live virus present in the vaccine.