Importantly, these medications increase the risk for severe complications of certain infections that may be related to travel, including tuberculosis, endemic mycoses, non-typhoidal salmonellosis, and leishmaniasis.15–18 Vaccine responses, particularly to influenza and pneumococcal vaccines, may be diminished in people taking TNF blockers, but vaccination is nevertheless recommended.19–21 Live-virus vaccination is contraindicated in people receiving immune-modulating agents, such as TNF blockers. This evidence concerns the gene TNF and influenza.