gms | German Medical Science

Introduction: Infections represent a significant threat for SOT candidates and recipients, with higher attack rates and risks for severe and complicated illness especially after SOT. Despite existing recommendations, SOT candidates and recipients may not be immune because of insufficient routine immunization and/or limited magnitude and duration of vaccine-induced protection in end-stage disease and/or use of immunosuppressive regimens.

Objectives: Primary objective: to evaluate vaccine-induced seroprotection before and after SOT. Secondary objective: to evaluate the acceptability of influenza and pneumococcal immunization in SOT candidates.

Methods: Since January 2014, a systematic approach was implemented at the University Hospitals of Geneva (HUG): a vaccinology consultation was implemented for all adult (>18 years old) SOT candidates and recipients. At time of listing, vaccine history is taken and immunization status documented in a national electronic immunization registry (www.myvaccines.ch) which is accessible by physicians of the transplant center, physicians in charge of the patients in private practice and the patients themselves. Serological evaluation is performed, including antibodies to tetanus, measles, rubella, varicella and hepatitis A/B. One dose of 13-valent pneumoccocal conjugate vaccine and influenza immunization (before/during the influenza season) are offered to all candidates at time of listing. Insufficient immunity is identified and the first missing vaccines administered during the hospital workup, specific immunization instructions being sent to the physicians in charge to complete immunization schedule and to repeat serological analyses after immunization.

Results: Fourty-three patients were evaluated between January 1^st and March 15, 2014.

Twenty-two patients were SOT candidates (liver: 13; liver + kidney: 3; heart: 3; kidney: 2; lung: 1), with a median age of 57 years (range 42-68) and a male-to-female gender ratio of 4.5. Antibodies to tetanus were present (>100 UI/L) in most (18/22, 81%) and often at sufficient titers to confer sustained protection (13/22 (60%) >500 UI/L). Past HBV infection was documented in 6/22 (27%). Only 2 of the remaining 16 candidates (12.5%) had been immunized and both had anti-HBS antibodies >10 UI/L, but < 100 UI/L. Only 11/22 (50%) SOT candidates had been immunized against influenza in 2013/2014. Influenza immunization was administered to 7 patients during the pre-SOT workup. Pneumococcal (PCV13) immunization was proposed to all and immediately accepted by 19/22 (86%) candidates.

Twenty-one patients were SOT recipient (liver: 8, kidney: 7; liver + kidney: 1; islet of Langerhans or pancreas +/- kidney: 4; lung: 1;). Their median age was 53 years (range 29-68) with a male-to-female gender ratio of 2. 19/21 patients had detectable (>100 UI/L) antibodies to tetanus, mostly (18/21, 86%) at a titer >500 UI/L sufficient for sustained protection. One patient had been infected with HBV. Among the remaining 20 patients, only 11 (55%) had been immunized. Most (8/11, 80%) had anti-HBS antibody >10 UI/L and 5/11 (50%) >100 UI/L. Remarkably, only 2/8 (25%) of liver SOT had a documented HBV immunization and only 1 with anti-HBS antibodies >10, but <100 UI/l. Influenza immunization (2013/2014) was only recorded for 14/21 (67%) of SOT recipients.

Conclusions: Adult organ end-stage disease patients referred to our center for pre-transplant workups are rarely (12.5%) immunized / protected against HBV. Vaccine recommendations were infrequently followed as only 55% of SOT recipients (including 25% of liver recipients), had been vaccinated against HBV. Tetanus immunity, resulting from routine immunization, was more prevalent (≥81%). This did not reflect vaccine refusal, as both influenza and pneumococcal immunization were readily accepted when recommended during pre-transplant workup. Despite the small sample size of this 10-week initial period, this demonstrates the need for a systematic review of vaccine history and immunity in SOT candidates and recipients.