**5. Infectious evaluation and vaccination**

A complete serologic status of the potential recipient should always be obtained before HTx, especially considering previous exposure to cytomegalovirus and Mycobacterium tuberculosis, as it is crucial when defining infectious prophylaxis after HTx.

The human immunodeficiency virus infection with undetectable viral load is not a contraindication to HTx at present, although each case must be assessed individually and retroviral treatment should be adapted to avoid interference with calcineurin inhibitors [48].

Patients with chronic hepatitis B infection (defined by the presence of hepatitis B surface antigen) have equal survival rates compared to the rest of the cohort, unless there is significant liver disease. In this setting, liver cirrhosis should be ruled out with biopsy if necessary, and antivirals should be given in order to lower viral load, since there is a risk of reactivation of the disease with immunosuppression after HTx. Similarly, when hepatitis C virus serology is positive, the quantitative viral load and degree of liver disease must be determined. If circulating HCV is detected, the disease is active and antiviral treatment must be prescribed to eliminate the virus. An altered hepatic function, which is not justified by HF, or a liver biopsy with evidence of cirrhosis, should be considered an absolute contraindication [30].

Finally, vaccination against hepatitis A and B viruses is also recommended if not previously given, as well as vaccination against Pneumococcus (every 5 years), Influenza (annual) and *Haemophilus influenzae* before the HTx [29].
