Vaccinations, response, and controls before and after intestinal transplantation in children

Poor response to hepatitis A vaccination in hematopoietic stem cell transplant recipients

BACKGROUND

Hepatitis A virus (HAV) infection is highly prevalent in developing countries. In countries experiencing a shift from intermediate/high endemicity to low endemicity, the World Health Organization recommends the incorporation of HAV vaccine into the national vaccination calendar for children aged ≥1 year. Since HAV antibodies wane over time, most HSCT revaccination guidelines advise vaccination as optional, following the country recommendation. However, no study has evaluated the serological response to HAV vaccine in allogeneic HSCT recipients.

METHODS

We conducted a prospective study in 46 HSCT recipients who received two doses of inactivated HAV vaccine. Blood samples were taken before vaccination to determine HAV prevalence rates, and before and 4-6 weeks after the second dose. Specific anti-HAV antibodies were detected by a competitive commercial enzyme immune assay.

RESULTS

Patients received the first dose of vaccine at a median of 332.5 (120-4134) days after HSCT. Median absolute lymphocyte count at vaccination was 1947 (696-12 500)/mm³ . The seroprevalence rate was 93.5% at inclusion. Although safe and well tolerated, the serological response to HAV vaccine in susceptible patients was poor (33%), and no boost effect was observed in seropositive patients.

CONCLUSIONS

In areas with intermediate/high seroprevalence of HAV, serology should be recommended prior to referral to vaccination. The mechanisms of antibody interference and how to overcome T-cell function deficiency need to be better understood in transplant populations receiving HAV vaccine. Alternative schedules of HAV vaccination should be evaluated in prospective trials.

Life of patients 10 years after a successful pediatric intestinal transplantation in Europe

A multicenter Europe-wide single-point study in intestinal transplantation (ITx) centers was conducted to identify and describe patients surviving for more than 10 years after ITx in childhood. The health and nutritional status, care requirements and psychosocial status were recorded. Among 120 transplanted before 2005, 38 patients with a functioning graft were included. Thirty (79%) had an exclusive oral diet, seven (18%) complimentary enteral nutrition for eating disorders, and one a combination of parenteral and enteral nutrition. They received a median of five drugs daily and five had a stoma. We did not observe any catch-up growth during the 10 years of follow-up. In the previous five years, 22 patients needed unplanned hospitalization with a median in-patient stay of six days. Eleven needed ongoing psychiatric follow-ups, and nine needed other specialist follow-ups. An increasing independency from parents was seen after the age of 18, with three having a stable employment and 31 pursuing education. Despite a good graft function, growth may not catch up. The burden of medical care remains high in the long term. This has to be closely followed in a multidisciplinary setting to improve long-term quality of life in these patients.

Innovative Approaches to Improve Anti-Infective Vaccine Efficacy

Safe and efficacious vaccines are arguably the most successful medical interventions of all time. Yet the ongoing discovery of new pathogens, along with emergence of antibiotic-resistant pathogens and a burgeoning population at risk of such infections, imposes unprecedented public health challenges. To meet these challenges, innovative strategies to discover and develop new or improved anti-infective vaccines are necessary. These approaches must intersect the most meaningful insights into protective immunity and advanced technologies with capabilities to deliver immunogens for optimal immune protection. This goal is considered through several recent advances in host-pathogen relationships, conceptual strides in vaccinology, and emerging technologies. Given a clear and growing risk of pandemic disease should the threat of infection go unmet, developing vaccines that optimize protective immunity against high-priority and antibiotic-resistant pathogens represents an urgent and unifying imperative.