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Infectious diseases are a major cause of morbidity and mortality in patients with chronic liver disease, both before and after liver transplantation. Impaired humoral and cellular immunity in these patients is attributable to liver disease itself but also to immunosuppressive agents.1–10 Active immunization is an effective way to protect transplant recipients against certain infectious agents. Patients should be immunized against common infections such as pneumococci and influenza as soon as chronic liver disease is diagnosed.11–14 Vaccination against hepatitis A and B virus is also recommended for these patients who are vulnerable to viral coinfection. Furthermore, infections can contribute to rejection of the transplanted organ and to the subsequent development of certain types of cancers. Following transplantation, the risk for infectious diseases increases and the serologic response to vaccination decreases due to immunosuppressive agents. For this reason, efforts should be made to vaccinate patients early in the course of liver disease.
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Protection upon vaccination results from the complex interaction of humoral and cellular components of the immune system.15,16
Humoral responses to vaccines are significantly reduced after solid organ transplantation by immunosuppressive agents, organ type, organ function and age.10
High variability of the antibody response was observed for all vaccines, possible due to multiple factors (varying seasonal composition of the influenza vaccine, different vaccination schedules and doses, different immunosuppressive agents, presence of viral coinfections, etc.).
However, despite the reduced humoral response and low antibodies titers, vaccine-specific cellular immunity can be present.15
Inactivated vaccines are safe in the posttransplant patient receiving immunosuppressive therapy. Live vaccines are generally contraindicated in adult immunosuppressed patients. Patients can shed viruses up until 5 weeks after vaccination with live viruses. Ideally, transplant surgery should not be performed 1 to 2 months after immunization with a live vaccine.
However, based on recent data, vaccination with live attenuated vaccines (varicella-zoster virus [VZV], measles, mumps, rubella [MMR]) should be considered when the risk of exposure is high.10
Guidelines and recommendations for vaccination of solid organ transplantation recipients are poorly supported by evidence and are largely extrapolated from what is known in the immune-competent population.15
If possible, transplant patients should receive all age-appropriate and risk-specific vaccines recommended by the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention prior to transplantation.17–20
As important as the immunization of the transplant recipients is the immunization of close household contacts and health care workers who will care for the immune-suppressed patient. Updating the vaccination of household contacts and health care workers will minimize the transplant patient’s exposure to certain viral and bacterial agents. It is safe to immunize close contacts of transplant patients with live viruses except for the typhoid, smallpox, and oral polio vaccines.
Monitoring antibody titers 1 or 2 months after a vaccination series can be useful to check for seroconversion.
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