Immunisations in solid-organ transplant recipients

Live-attenuated vaccination for measles, mumps, and rubella in pediatric liver transplantation

BACKGROUND

Infections are a serious short- and long-term problem after pediatric organ transplantation. In immunocompromised patients, they can lead to transplant rejection or a severe course with a sometimes fatal outcome. Vaccination is an appropriate means of reducing morbidity and mortality caused by vaccine-preventable diseases. Unfortunately, due to the disease or its course, it is not always possible to establish adequate vaccine protection against live-attenuated viral vaccines (LAVVs) prior to transplantation. LAVVs such as measles, mumps, and rubella (MMR) are still contraindicated in solid organ transplant recipients receiving immunosuppressive therapy (IST), thus creating a dilemma.

AIM

This review discusses whether, when, and how live-attenuated MMR vaccines can be administered effectively and safely to pediatric liver transplant recipients based on the available data.

MATERIAL AND METHODS

We searched PubMed for literature on live-attenuated MMR vaccination in pediatric liver transplantation (LT).

RESULTS

Nine prospective observational studies and three retrospective case series were identified in which at least 833 doses of measles vaccine were administered to 716 liver transplant children receiving IST. In these selected patients, MMR vaccination was well tolerated and no serious adverse reactions to the vaccine were observed. In addition, an immune response to the vaccine was demonstrated in patients receiving IST.

CONCLUSION

Due to inadequate vaccine protection in this high-risk group, maximum efforts must be made to ensure full immunization. MMR vaccination could also be considered for unprotected patients after LT receiving IST following an individual risk assessment, as severe harm from live vaccines after liver transplantation has been reported only very rarely. To this end, it is important to establish standardized and simple criteria for the selection of suitable patients and the administration of the MMR vaccine to ensure safe use.

Low switched memory B cells are associated with no humoral response after SARS-CoV-2 vaccine boosters in kidney transplant recipients

Introduction

The humoral response after SARS-CoV-2 vaccination and boosters in kidney transplant recipients (KTRs) is heterogeneous and depends on immunosuppression status. There is no validated immune measurement associated with serological response in clinical practice. Multicolor flow cytometric immunophenotyping could be useful for measuring immune response. This study aimed to study B- and T-cell compartments through Standardized EuroFlow PID Orientation after SARS-CoV-2 vaccination and their association with IgG SARS-CoV-2 seropositivity status after two doses or boosters.

Methods

We conducted a multicenter prospective study to evaluate humoral response after SARS-CoV-2 vaccination in KTRs. Heterologous regimen: two doses of inactivated SARS-CoV-2 and two boosters of BNT162b2 mRNA (n=75). Homologous vaccination: two doses of BNT162b2 mRNA and one BNT162b2 mRNA booster (n=13). Booster doses were administrated to KTRs without taking into account their IgG SARS-CoV-2 seropositivity status. Peripheral blood samples were collected 30 days after the second dose and after the last heterologous or homologous booster. A standardized EuroFlow PID Orientation Tube (PIDOT) and a supervised automated analysis were used for immune monitoring cellular subsets after boosters.

Results

A total of 88 KTRs were included and divided into three groups according to the time of the first detected IgG SARS-CoV-2 seropositivity: non-responders (NRs, n=23), booster responders (BRs, n=41), and two-dose responders (2DRs, n=24). The NR group was more frequent on mycophenolate than the responder groups (NRs, 96%; BRs, 80%; 2DRs, 42%; p=0.000). Switched memory B cells in the 2DR group were higher than those in the BR and NR groups (medians of 30, 17, and 10 cells/ul, respectively; p=0.017). Additionally, the absolute count of central memory/terminal memory CD8 T cells was higher in the 2DR group than in the BR and NR groups. (166, 98, and 93 cells/ul, respectively; p=0.041). The rest of the T-cell populations studied did not show a statistical difference.

Conclusion

switched memory B cells and memory CD8 T-cell populations in peripheral blood were associated with the magnitude of the humoral response after SARS-CoV-2 vaccination. Boosters increased IgG anti-SARS-CoV-2 levels, CM/TM CD8 T cells, and switched MBCs in patients with seropositivity after two doses. Interestingly, no seropositivity after boosters was associated with the use of mycophenolate and a lower number of switched MBCs and CM/TM CD8 T cells in peripheral blood.

Efficacy and Safety of Hepatitis B Virus Vaccination Following Hepatitis B Immunoglobulin Withdrawal After Liver Transplantation

BACKGROUND

Hepatitis B immunoglobulin (HBIG) and oral nucleoside/nucleotide analogs have been the mainstay of hepatitis B virus (HBV) prophylaxis after liver transplantation. However, long-term HBIG administration could have disadvantages, such as an increase in medical costs and the development of mutant HBV strains. This study aimed to investigate the safety and efficacy of HBV vaccination after the withdrawal of HBIG after liver transplantation.

METHODS

This prospective open-label single-arm observational clinical trial enrolled 41 patients who underwent liver transplantation between 2010 and 2016 because of a condition related to chronic HBV infection. At the time of enrollment, all patients had taken entecavir and discontinued HBIG administration. When hepatitis B surface antibody titer was undetectable after the withdrawal of HBIG, a recombinant HBV vaccine was injected intramuscularly at month 0, 1, and 6.

RESULTS

After excluding 5 patients who dropped out and 2 patients who had a persistent hepatitis B surface antibody titer, 9 (26.5%) of 34 patients had a positive vaccination response. The median hepatitis B surface antibody titer at seroconversion was 86 (12-1000) IU/L, and those at the end of follow-up were 216 (30-1000) IU/L. No patients experienced HBV recurrence during the study period. Sex (female, odds ratio 32.91 [1.83-592.54], P = .018) and the dosing interval of HBIG before withdrawal (≥90 days, 16.21 [1.21-217.31], P = .035) were independent contributing factors for positive response to the vaccination.

CONCLUSION

HBV vaccination still deserves consideration as active immunoprophylaxis after liver transplantation because it could provide added immunity to nucleoside/nucleotide analogs monotherapy with excellent cost-effectiveness.

Deceased Donor Predictors for Pediatric Liver Allograft Utilization

BACKGROUND

The number of pediatric deceased organ donors has recently declined, and the nonutilization of pediatric liver allografts has limited the development of liver transplantation. We determined the utilization rate of pediatric livers and identified risk factors for graft discard.

METHODS

We used data from the Scientific Registry of Transplant Recipients database from January 1, 2000, to December 31, 2012. The trends of pediatric liver donors and utilization rates were analyzed. Donor risk factors that impacted the graft use of pediatric livers were measured. Logistic regression modelling was performed to evaluate graft utilization and risk factors.

RESULTS

A total of 11,934 eligible pediatric liver donors were identified during this period. A total of 1191 authorized liver grafts did not recover or recovered without transplantation. Factors including pediatric donors >1 year of age (odds ratio [OR] = 2.956, 95% confidence interval [CI] 2.494-3.503, P < .001), nonhead trauma (OR = 2.243, 95% CI 1.903-2.642, P < .001), lack of heartbeat (OR = 7.534, 95% CI 5.899-9.623, P < .001), hepatitis B surface antigen positivity (OR = 4.588, 95% CI 1.021-20.625, P = .047), anti-hepatitis C virus positivity (OR = 4.691, 95% CI 1.352-16.280, P = .015), total bilirubin >1 mg/dL (OR = 1.743, 95% CI 1.469-2.068, P < .001), and blood urea nitrogen >21 mg/dL (OR = 1.941, 95% CI 1.546-2.436, P < .001) were significantly related to graft nonutilization. Steroids or diuretics administered prerecovery were significantly related to graft utilization (OR = 0.684, 95% CI 0.581-0.806, P < .001; OR = 0.744, 95% CI 0.634-0.874, P < .001; respectively).

CONCLUSIONS

The pediatric liver allograft utilization rate and risk factors for nonutilization of grafts were determined.

Vaccines in pediatric transplant recipients-Past, present, and future

Infections significantly impact outcomes for solid organ and hematopoietic stem cell transplantation in children. Vaccine-preventable diseases contribute to morbidity and mortality in both early and late posttransplant time periods. Several infectious diseases and transplantation societies have published recommendations and guidelines that address immunization in adult and pediatric transplant recipients. In many cases, pediatric-specific studies are limited in size or quality, leading to recommendations being based on adult data or mixed adult-pediatric studies. We therefore review the current state of evidence for selected immunizations in pediatric transplant recipients and highlight areas for future investigation. Specific attention is given to studies that enrolled only children.

Vaccination practices in End Stage Renal Failure and Renal Transplantation; Review of current guidelines and recommendations

Due to the increased burden of infectious complications following solid organ transplantation, vaccination against common pathogens is a hugely important area of discussion and application in clinical practice. Reduction in infectious complications will help to reduce morbidity and mortality post-transplantation. Immunisation history is invaluable in the work-up of potential recipients. Knowledge of the available vaccines and their use in transplant recipients, donors and healthcare providers is vital in the delivery of quality care to transplant recipients. This article will serve as an aide-memoire to transplant physicians and health care professionals involved in managing transplant recipients as it provides an overview of different types of vaccines, timing of vaccination, vaccines contraindicated post solid organ transplantation and travel vaccines.

Active immunization for prevention of De novo hepatitis B virus infection after adult living donor liver transplantation with a hepatitis B core antigen-positive graft

De novo hepatitis B virus (DNHB) infections may occur in recipients who do not receive prophylaxis after liver transplantation (LT) with antibody to hepatitis B core antigen (anti-HBc)-positive donor grafts. Active immunization has been shown to prevent DNHB in pediatric recipients. Our aim is to investigate the efficacy of HBV vaccination for preventing DNHB in adult living donor liver transplantation (LDLT). In total, 71 adult antibody to hepatitis B surface antigen (anti-HBs)-negative LDLT patients who received anti-HBc+ grafts from 2000 to 2010 were enrolled into this study. Patients were given hepatitis B virus vaccinations with the aim of achieving anti-HBs > 1000 IU/L before transplant and >100 IU/L after transplant. The cohort was stratified into 3 groups: patients with pretransplant anti-HBs titer of > 1000 IU/L without the need for posttransplant prophylaxis (group 1, n = 24), patients with pretransplant low titer of <1000 IU/L who were given posttransplant lamivudine prophylaxis and responded appropriately to posttransplant vaccination by maintaining anti-HBs titers of > 100 IU/L (group 2, n = 30), and low titer nonresponders (anti-HBs titer of < 100 IU/L despite vaccination), for whom lamivudine was continued indefinitely (group 3, n = 17). All DNHB occurred in group 3 patients with posttransplant anti-HBs levels of < 100 IU/L, with an incidence rate of 17.6% compared with 0% in patients with posttransplant anti-HBs levels of > 100 IU/L (P = 0.001). A pretransplant anti-HBs level of >1000 IU/L was significantly associated with early attainment and a sustained level of posttransplant anti-HBs of >100 IU/L (P < 0.001). Active immunization is effective in preventing DNHB in adult LDLT if the posttransplant anti-HBs level is maintained above 100 IU/L with vaccination. Antiviral prophylaxis can be safely discontinued in patients who obtain this immunity. Liver Transplantation 23 1266-1272 2017 AASLD.

Enteroviruses and Parechoviruses

Infections with enteroviruses and human parechoviruses are highly prevalent, particularly in neonates, where they may cause substantial morbidity and mortality. Individuals with B-cell-related immunodeficiencies are at risk for severe enteroviral infections, usually a chronic and fatal meningoencephalitis. In transplant recipients and patients with malignancy, enterovirus infections typically involve the respiratory tract, but cases of severe, disseminated infection have been described. The mainstay of diagnosis for enterovirus and human parechovirus infections involves the use of molecular diagnostic techniques. However, routine nucleic acid-detection methods for enteroviruses will not detect human parechoviruses. Laboratory diagnosis of these viral infections is important in determining a patient's prognosis and guiding clinical management.

Influenza Vaccine Antibody Responses in Lung Transplant Recipients

Context

Lung transplant recipients are at high risk of morbidity and mortality from influenza infection because of altered lung physiology and immunosuppression. Annual influenza immunization is recommended, but the ability to mount an antibody response may be limited by immunosuppressant medications.

Objective

To compare the antibody response rate to influenza vaccine in lung transplant recipients to healthy controls.

Design

Open label study

Setting

Lung transplant clinic and General Clinical Research Center at a university hospital.

Subjects

Sixty-eight single and bilateral lung transplant recipients and 35 healthy controls were enrolled in October and November 2002.

Methods

Each individual underwent blood sampling before receiving the 2002–2003 influenza vaccine and 4 weeks later. Influenza antibody concentrations were measured by hemagglutination inhibition assay. Vaccine response rates (antibody concentration >40 hemagglutination units and at least 4-fold increase in antibody concentration) were compared using χ2. The influence of specific immunosuppressants on vaccine response was compared.

Results

The influenza vaccine response rate for lung transplant recipients was 29/68 (43%) and 22/35 (63%) for the healthy individuals ( Pž < .05; χ2). Among the recipients, mycophenolate mofetil was associated with poorer influenza vaccine antibody response (> 40 hemagglutination units) (62% vs 91%; Pž = .01), whereas sirolimus (91% vs 63%; Pž = .02) was associated with better influenza antibody response compared to those not taking mycophenolate mofetil or sirolimus, respectively.

Conclusion

Lung transplant recipients had lower influenza vaccine response rates than healthy individuals. Influenza vaccine antibody response is influenced by concomitant administration of mycophenolate mofetil or sirolimus. Future studies should measure protection from influenza infection conferred by immunization and alternative vaccination strategies.

Immunizations in solid organ and hematopoeitic stem cell transplant patients: A comprehensive review

The Solid Organ Transplantation (SOT) and Haematopoietic Stem Cell Transplantation (HSCT) population is continuously increasing as a result of broader indications for transplant and improved survival. Infectious diseases, including vaccine-preventable diseases, are a significant threat for this population, primarily after but also prior to transplantation. As a consequence, clinicians must ensure that patients are optimally immunized before transplantation, to provide the best protection during the early post-transplantation period, when immunosuppression is the strongest and vaccine responses are poor. After 3-6 months, inactivated vaccines immunization can be resumed. By contrast, live-attenuated vaccines are lifelong contraindicated in SOT patients, but can be considered in HSCT patients at least 2 years after transplantation, if there is no immunosuppression or graft-versus-host-disease. However, because of the advantages of live-attenuated over inactivated vaccines--and also sometimes the absence of an inactivated alternative--an increasing number of prospective studies on live vaccine immunization after transplantation are performed and give new insights about safety and immunogenicity in this population.

De novo hepatitis b prophylaxis with hepatitis B virus vaccine and hepatitis B immunoglobulin in pediatric recipients of core antibody-positive livers

The use of hepatitis B core antibody-positive (HBcAb+) grafts for liver transplantation (LT) has the potential to safely expand the donor pool, as long as proper prophylaxis against de novo hepatitis B (DNHB) is employed. The aim of this study was to characterize the longterm outcome of pediatric LT recipients of HBcAb + liver grafts under a prophylaxis regimen against DNHB using hepatitis B virus (HBV) vaccine and hepatitis B immunoglobulin (HBIG). From June 1996 to February 2013, 49 patients receiving pediatric LT at our center were from HBcAb + donors. Forty-one patients who received DNHB prophylaxis according to our protocol were included in this analysis. Our DNHB prophylaxis protocol consists of HBV vaccine intramuscular injections given intermittently to maintain anti-hepatitis B surface antibody (HBsAb) titers above 100 IU/L. HBIG was also used during the first posttransplant year with a target anti-HBsAb titer level above 200 IU/L. There were 19 boys and 22 girls. Median age was 1.0 year (range, 4 months to 16 years). Median follow-up time was 66 months after transplant. Median annual number of HBV vaccine injections was 0.8 per year (range, 0-1.8 per year). Four patients did not require any HBV vaccine injections during follow-up. One patient with DNHB was encountered during the follow-up period (1/41, 2.4%). DNHB was diagnosed at 3.5 years after transplant, when hepatitis B surface antigen was positive upon routine follow-up serologic testing. Anti-HBsAb titer was 101.5 IU/L at the time. No grafts were lost because of DNHB-related events. Overall survival of the 41 recipients of HBcAb + grafts who received DNHB prophylaxis was 92.3% at 10 years after transplant. In conclusion, longterm prophylaxis against DNHB with HBV vaccine in pediatric LT recipients of HBcAb + grafts was safe and effective in terms of DNHB incidence as well as graft and patient survival.

Live virus vaccines in transplantation: friend or foe?

Solid organ and hematopoietic stem cell transplant recipients may be exposed to diseases which may be prevented through live attenuated virus vaccines (LAVV). Because of their immunosuppression, these diseases can lead to severe complications in transplant recipients. Despite increasing evidence regarding the safety and effectiveness of certain LAVV, these vaccines are still contraindicated for immunocompromised patients, such as transplant recipients. We review the available studies on LAVV, such as varicella zoster, measles-mumps-rubella, influenza, yellow fever, polio, and Japanese encephalitis vaccines in transplant patients. We discuss the current recommendations and the potential risks, as well as the expected benefits of LAVV immunization in this population.

Vaccination of the immunocompromised child

The development of vaccination is a major achievement in modern medicine. However, children treated with immunosuppression may not at all, or only in part, receive routine immunization due to uncertainty of its risks and effect. There is a substantial lack of pediatric studies concerning the efficacy and safety of vaccination in this patient group. Experience from similar adult groups and children with HIV infection can be used as a model for other disease categories. With increasing knowledge of the immunologic basis of vaccination and how immunosuppressive drugs interfere with the immune system, improved vaccines could be tailored, and adequate, individualized guidelines issued.

Cyclosporine combined with nonlytic interleukin 2/Fc fusion protein improves immune response to hepatitis B vaccination in a mouse skin transplantation model

BACKGROUND

Improving immune responses to vaccination in immunosuppressed patients is extremely important. Previously, we observed that cyclosporine (CsA) combined with a nonlytic interleukin (IL)-2/fragment crystallizable (Fc) fusion protein induces immune tolerance to mouse skin transplantations. In the present study, we asked whether this combination improved hepatitis B (HBV) vaccine efficacy in immunosuppressed mice while also prolonging skin graft survival.

METHODS

After C57BL/6 mice received DBA/2 skin grafts, they were administered a 14-day course of CsA (30 mg/kg intraperitoneal) combined with IL-2/Fc (1 μg, intraperitoneal). HBV vaccine (2 μg) was injected intramuscularly on the day of skin transplantation. On day 14, the serum levels of hepatitis B surface antibody (HBsAb), IL-4, IL-10, interferon (IFN-γ), and IL-2 were measured by enzyme-linked immunosorbent assay. We assessed the percentages of CD4(+)CXCR5(+) follicular T helper cells, CD4(+)FoxP3(+) regulatory T cells (Treg) and expressions of IL-17, IL-21, FoxP3, Bcl-6 in the spleen. Animals were divided into four groups: control, vaccine-treated, CsA + vaccine-treated, CsA + IL-2/Fc + vaccine-treated hosts.

RESULTS

Combination therapy significantly increased HBsAb levels and also prolonged skin graft survival. Serum levels of Th1 cytokines IL-2 and IFN-γ were significantly higher in the combination group, while Th2 cytokines, IL-4 and IL-10 were lower. Combined treatment increased the percentage of Treg and the expression of Foxp3 and IL-21, meanwhile inhibiting the expression of Bcl-6. But the percentage of Tfh did not significantly change among the groups.

CONCLUSIONS

These observations suggested that a combination of CsA and IL-2/Fc fusion protein enhanced immune responses after HBV vaccination and prolonged skin graft survival.

Long-term outcome after liver transplantation

Liver transplantation is a life-saving therapy for patients with end-stage liver disease, acute liver failure, and liver tumors. Over the past 4 decades, improvements in surgical techniques, peritransplant intensive care, and immunosuppressive regimens have resulted in significant improvements in short-term survival. Focus has now shifted to addressing long-term complications and improving quality of life in liver recipients. These include adverse effects of immunosuppression; recurrence of the primary liver disease; and management of diabetes, hypertension, dyslipidemia, obesity, metabolic syndrome, cardiovascular disease, renal dysfunction, osteoporosis, and de novo malignancy. Issues such as posttransplant depression, employment, sexual function, fertility, and pregnancy must not be overlooked, as they have a direct impact on the liver recipient's quality of life. This review summarizes the latest data in long-term outcome after liver transplantation.

[Daily life, pregnancy, and quality of life after liver transplantation]

It is now accepted that patients with a liver transplantation regain the ability to lead a normal life within months of surgery, but at the price of lifetime immunosuppressive treatment and specific regular surveillance. A balanced and diversified diet, together with regular physical activity is necessary to prevent, limit, or delay the development of the cardiovascular complications that determine the prognosis for long-term survival. Attenuated live vaccines are contraindicated in patients treated with immunosuppressants to avoid the risk of reversion of the attenuation of the virus or bacteria. Travel abroad is possible to places with good sanitary conditions, if the patient increases his or her vigilance for any contagious infection. The global incidence of cancer is higher than in the general population, justifying specific and regular testing and clinical monitoring. A planned pregnancy is possible in patients stabilized after liver transplantation, and prognosis is most often good for mother and child. Early multidisciplinary management is essential because of the elevated risks of fetal growth restriction and preterm delivery. The global perception of quality of life increases after liver transplantation, but remains lower than in healthy subjects.

[Recommendations before travelling for renal transplant patients]

Travel is now a reasonable objective of CKD patients after renal transplantation. However, immunosuppressive treatment makes them particularly susceptible to infections and may interfere with vaccinations and other drugs. Travel in countries with low health level should be strongly discouraged in the first six months after transplantation or following an acute event. Otherwise, specific consultations should be arranged to prepare the patient as soon as possible. Vaccinations should be started early before departure. Specific immunisations include vaccines against hepatitis A, typhoid, meningococcus and rabies in some cases. Living vaccines are formally contra-indicated. Particular attention should be paid for protection against insects because this is the only effective measure against diseases. In the case of malaria, it should be complemented by adapted chemoprophylaxis that should be started 15 days before the departure date. Advice on hygiene measures should be clarified because this can prevent numerous infections, especially of the digestive tract. Advice on the management of diarrhoea is essential, especially in terms of preventing dehydration. Finally, advice about transport and physical risks, especially those related to sun exposure, should also be addressed.

Vaccination in adults with auto-immune disease and/or drug related immune deficiency: results of the GEVACCIM Delphi survey

INTRODUCTION

There are insufficient data regarding the efficacy and safety of vaccination in patients with auto-immune disease (AID) and/or drug-related immune deficiency (DRID). The objective of this study was to obtain professional agreement on vaccine practices in these patients.

METHODS

A Delphi survey was carried out with physicians recognised for their expertise in vaccinology and/or the caring for adult patients with AID and/or DRID. For each proposed vaccination practice, the experts' opinion and level of agreement were evaluated.

RESULTS

The proposals relating to patients with AID specified: the absence of risk of AID relapse following vaccination; the possibility of administering live virus vaccines (LVV) to patients not receiving immunosuppressants; the pertinence of determining protective antibody titre before vaccination; the absence of need for specific monitoring following the vaccination. The proposals relating to patients with DRID specified that a 3-6 month delay is needed between the end of these treatments and the vaccination with LVV. There is no contraindication to administering LVV in patients receiving systemic corticosteroids prescribed for less than two weeks, regardless of their dose, or at a daily dose not exceeding 10mg of prednisone, if this involves prolonged treatment. Out of 14 proposals, the level of agreement between the experts was "very good" for eleven, and "good" for the remaining three.

CONCLUSION

Proposals for vaccine practices in patients with AID and/or DRID should aid with decision-making in daily medical practice and provide better vaccine coverage for these patients.

Response to booster hepatitis B vaccines in liver-transplanted children primarily vaccinated in infancy

BACKGROUND

A hepatitis B virus (HBV) universal vaccination program for infants was implemented for 24 years in Taiwan. Most of the children who received organ transplantation were primarily vaccinated before transplantation. This study investigated the efficacy of HBV vaccination and booster responses in children after liver transplantation (LT).

METHODS

Totally 31 children were enrolled. They were clinically stable for more than 1 year after LT. Twenty of them kept a titer of antibody to hepatitis B surface antigen (anti-HBs) more than 10 mIU/mL and received no booster, while 11 received one booster because their anti-HBs titers were less than 10 mIU/mL. Cellular immunity was checked by enzyme-linked immunospot assay with interferon-gamma surrogated for T-helper 1 cells and interleukin-5 for T-helper 2 before and after booster vaccine.

RESULTS

One of the non-boosters had de novo HBV infection after LT and recovered to be anti-HBs positive. The first booster restored an adequate titer in 64% (7/11) of those with anti-HBs titer less than 10 mIU/mL after LT. The four patients who failed the first booster responded well to the second dose. After the booster, the mononuclear cells of all 11 had more than one spot-forming cell for interferon-gamma or interleukin-5. Transplanted girls maintained a higher antibody titer than boys.

CONCLUSION

Primary HBV vaccination or the booster dose(s) of HBV vaccine could provide adequate humoral and cellular immunity in children with LT.

Immune responsiveness and protective immunity after transplantation

The growing success of solid organ transplantation poses unique challenges for the implementation of effective immunization strategies. Although live attenuated vaccines have proven benefits for the general population, immunosuppressed patients are at risk for unique complications such as infection from the vaccine because of lack of both clearance and containment of a live attenuated virus. Moreover, while vaccination strategies using killed organisms or purified peptides are believed to be safe for immunosuppressed patients, they may have reduced efficacy in this population. The current lack of knowledge of the basic safety and efficacy of vaccination strategies in the immunosuppressed has limited the development of guidelines regarding vaccination in this population. Recent fears of influenza pandemics and potential attacks by weaponized pathogens such as smallpox heighten the need for increased knowledge. Herein, we review the current understanding of the effects of immunosuppressants on the immune system and the ability of the suppressed immune system to respond to vaccination. This review highlights the need for systematic, longitudinal studies in both humans and nonhuman primates to understand better the defects in innate and adaptive immunity in transplant recipients, thereby aiding the development of strategies to vaccinate these individuals.

Active immunization to prevent de novo hepatitis B virus infection in pediatric live donor liver recipients

This study aims to evaluate the efficacy of HBV vaccination as an alternative preventive measure against de novo HBV infection in pediatric living donor liver transplantation (LDLT). Sixty recipients were enrolled in this study. Thirty received grafts from anti-HBc(+) donors, and another 30 received grafts from anti-HBc(-) donors. HBV vaccine was given pretransplant to every candidate. Posttransplant, lamivudine was routinely given to recipients receiving anti-HBc(+) grafts for about 2 years. Forty-seven (78%) recipients achieved high levels of anti-HBs titer (>1000 IU/L). Two (3.3%) recipients developed de novo HBV infection where one received an anti-HBc(-) graft and another received an anti-HBc(+) graft. Both recipients were in the lower anti-HBs titer group (<1000 IU/L). The incidence of de novo HBV infection was significantly higher in the lower titer group (15.4% vs. 0%, p = 0.04). The median follow-up period was 51 months in recipients with anti-HBc(-) grafts and 57 months in those with anti-HBc(+) grafts. Active immunization is an effective method to prevent de novo HBV infection. It can result in high levels of anti-HBs titer (>1000 IU/L) which may prevent de novo HBV infection in pediatric patients with efficient primary vaccination undergoing LDLT.

Vaccination for the paediatrician

In most of Australia, general practitioners manage routine childhood vaccination schedules. However, paediatricians have an important role and need to have a thorough understanding of vaccination, particularly as it interfaces with other medical care. This is challenging as the Australian Standard Vaccination Schedule has undergone some substantial changes over the past 4 years, with the addition of meningococcal C conjugate, 7 valent pneumococcal conjugate, varicella and inactivated polio vaccines. Paediatricians are frequently the first port of call for advice on vaccination schedules for children with special needs, in relation to either vaccine efficacy or the risk of side effects. Categories include children with a range of chronic diseases, immunosuppression, premature infants and immigrant children. Advice about specific vaccines such as varicella, inactivated polio, influenza or multivalent vaccines and revaccination after adverse events is also often sought. The aim of this article is to update paediatricians on vaccination recommendations and relevant reference sources. The first part of this article discusses groups with special vaccination requirements. The second part discusses the use of individual vaccines in these children.

Extended double-dosage HBV vaccination after liver transplantation is ineffective, in the absence of lamivudine and prior wash-out of human Hepatitis B immunoglobulins

BACKGROUND

The recommended prophylaxis against hepatitis B virus recurrence after liver transplantation based on hepatitis B immunoglobulins and lamivudine is highly expensive. A recent study reported a significant anti-HBs (antibodies against hepatitis B surface antigen) response after a reinforced vaccination against hepatitis B virus, a result not confirmed in a study from our group. Concomitant lamivudine treatment and the achievement of complete washout of anti-hepatitis B-specific immunoglobulin prior to vaccination in our study could explain the contradiction.

AIMS

To test the efficacy of a reinforced anti-hepatitis B virus vaccination schedule without lamivudine and without previous anti-hepatitis B-specific immunoglobulin washout.

METHODS

A double reinforced course of S-recombinant hepatitis B virus vaccination was given to seven male patients who were transplanted for hepatitis B virus-related cirrhosis. Vaccination consisted of two cycles of three intramuscular double doses (40 microg), given at month 0, 1, 2, and 3, 4, 5, respectively. The first dose was given 2 weeks after stopping lamivudine and the intravenous administration of anti-HBs immunoglobulins. The latter was continued throughout the study and follow-up period to maintain an anti-HBs titre >100 IU/L.

RESULTS

At the end of both the first and the second vaccination cycle none of the patients developed an anti-HBs titre greater than the basal anti-HBs titre.

CONCLUSION

These data confirm and expand our previous data on the lack of effectiveness of conventional recombinant hepatitis B virus vaccination in liver transplant recipients.

Safety of live-virus vaccines for children with immune deficiency

PURPOSE

Conduct an integrative literature review to evaluate the safety and effectiveness of live-virus vaccines, namely, the measles, mumps, rubella, and varicella vaccines, in children who are immune compromised by exogenous medication either posttransplant or while undergoing maintenance chemotherapy for leukemia.

DATA SOURCES

Medline, MedlinePlus, EBSCO, PubMed, MD Consult, CINAHL, Clinical Pharmacology, ERIC, Biomedical Reference Collection-Basic, Health Source-Consumer Edition, Health Source-Nursing/Academic Edition, Ovid, CANCERLIT, and the Cochrane Library Online.

CONCLUSIONS

Because measles infection has a low incidence rate in the United States, it may be advisable not to vaccinate children who are immunocompromised and risk side effects of the vaccine. In contrast to measles infection, varicella has a higher incidence rate and poses a more imminent threat to those who are immunocompromised. Children who are immunosuppressed can receive the varicella vaccination; however, they should have regular titers drawn to confirm adequate protection against the disease and should receive boosters as deemed appropriate.

IMPLICATIONS FOR PRACTICE

The number of solid organ transplant recipients is steadily increasing with more than 600,000 solid organ transplantations worldwide since the first renal transplant in 1954. The steadily increasing numbers of pediatric patients surviving transplantation, coupled with increased life expectancy, accelerate the need for nurse practitioners to understand the management of these delicate patients following release from the transplant unit.

Immunization issues before and after solid organ transplantation in children

Solid-organ transplant recipients are at risk from various infectious diseases, many of which can be prevented by immunizations that could reduce morbidity and mortality. However, it is not uncommon for children requiring transplantation to have received inadequate or no immunizations pre-transplant. Every effort should be made to immunize transplant candidates early in the course of their disease according to recommended schedules prior to transplantation. It is also important to immunize their household contacts and healthcare workers. In this review, we summarize the major immunization issues for children undergoing transplantation, the data currently available on immunization safety and efficacy, and suggest immunization practices to reduce vaccine-preventable disease. There is a real need for a standardized approach to the administration and evaluation of immunizations in this group of patients.

Measles-associated encephalopathy in children with renal transplants

Two children, boys of 8 and 13 years, presented with measles-associated encephalopathy several years after kidney transplantation for congenital nephrotic syndrome. In the absence of prior clinical measles, the neurological symptoms initially eluded diagnosis, but retrospective analysis of stored samples facilitated the diagnosis of measles-associated encephalopathy without recourse to biopsy of deep cerebral lesions. Each had received a single dose of measles mumps and rubella vaccine before 12 months of age. Prior vaccination, reduction of immunosuppression and treatment with intravenous immunoglobulin and ribavirin may have contributed to their survival. Persistent measles virus RNA shedding, present in one child, was not controlled by treatment with i.v. ribavirin. Two years later, both patients continue to have functioning allografts with only minimal immunosuppression. These cases illustrate the difficulty in diagnosing measles-associated encephalopathy in the immunocompromised host, even in the era of molecular diagnostics, and highlight the renewed threat of neurological disease in communities with incomplete herd immunity.

Immunization with an adjuvant hepatitis B vaccine in liver transplant recipients: antibody decline and booster vaccination with conventional vaccine

Patients after orthotopic liver transplantation (OLT) due to hepatitis B virus (HBV)-related disease are at risk of endogenous hepatitis B reinfection and may receive life long prophylaxis with hepatitis B hyperimmunoglobulin (HBIG). In a previous study 16 of 20 OLT patients were immunized successfully with an adjuvant hepatitis B vaccine. To maintain protective antibody levels under immunosuppressive therapy, 11 of these patients were revaccinated with a double dosed conventional hepatitis B vaccine. Median interval between last vaccination and booster was 24 months (range 22-31 months). Antibody titres against hepatitis B surface antigen (anti-HBs) were monitored at the day of booster vaccination (day 0), at day 7 and day 28. At day 0, all vaccinees but one had anti-HBs titres greater than 500 IU/L (median 1,925 IU/L, range 196-7,612 IU/L). Maximum antibody titres after previous vaccination declined by a median of 82% (range 47-96%). After booster vaccination the anti-HBs titre increased significantly by a median factor of 2.42 (P<0.05). In conclusion, the majority of liver transplant recipients who previously had responded to adjuvant hepatitis B vaccine exhibited sufficient immunocompetence to produce a substantial antibody response after booster immunization with a conventional vaccine.

Fulminating varicella despite prophylactic immune globulin and intravenous acyclovir in a renal transplant recipient: should renal patients be vaccinated against VZV before transplantation?

We describe a case of fulminating varicella despite prophylactic immune globulin and intravenous acyclovir in a renal transplant recipient. This promoted a survey of all 383 adult patients awaiting a renal transplant in Scotland, which showed a low level of Varicella zoster virus (VZV) awareness but a willingness to consider vaccination if non immune. 359/363 serum samples tested were seropositive for VZV antibody giving a susceptibility to VZV of 1.2%. Although data on vaccination in adults with chronic kidney disease are limited, expert opinion is of the view that the benefits of vaccinating immunocompetent seronegative patients before transplantation are likely to outweigh the risks. We believe that adult patients awaiting a transplant in the UK should be tested for their susceptibility to VZV and that early vaccination should be offered to those who are both immunocompetent and seronegative.

Recommendations for the use of the 23-valent polysaccharide pneumococcal vaccine in adults: a Belgian consensus report

A multidisciplinary expert panel, appointed by the High Council for Public Health, evaluated the scientific evidence on which the recommendations for the appropriate use of the pneumococcal vaccine was based and reviewed the studies that became available since previous reports. The conclusions of the working group, presented in this manuscript, resulted in an update of the Belgian recommendations for pneumococcal vaccination.

Extended HBV vaccination in liver transplant recipients for HBV-related cirrhosis: report of two successful cases

The effectiveness of hepatitis B virus vaccination in liver transplant recipients for hepatitis B virus-related end-stage liver disease is controversial. We report two successful cases, who developed sustained protection after long-term vaccination. Case 1. A 58-year-old male, transplanted 9 years earlier, received three intramuscular monthly doses of 40 microg of recombinant S vaccine and developed an anti-hepatitis B surface titre of 154 IU/L. After an additional 40 microg dose, he reached an anti-hepatitis B surface peak of 687 IU/L and then maintained a "protective" titre (>100 IU/L) without further vaccinations for the next 40 months. At this time, revaccination with three monthly doses of 40 microg resulted in an anti-hepatitis B surface titre greater than 25,000 IU/L, sustained over time. Case 2. A 56-year-old woman, transplanted 8 years earlier, first received three intramuscular monthly doses of 40 microg of S vaccine without developing any detectable anti-HBs. She was then given multiple intradermal vaccine doses which resulted in a titre of 37 IU/L. Next, after readministration of three 40 microg intramuscular monthly doses, she developed an anti-HBs titre of 280 IU/L. In the following 4 years, the anti-HBs titre dropped below 100 IU/L four times (at month 20, 30, 38 and 44) and readministration of single 40 microg doses of vaccine was always sufficient to restore a protective titre. Conclusion. Extended HBV vaccination may afford valid protection against HBV recurrence in selected liver transplant recipients.

Response to an experimental HBV vaccine permits withdrawal of HBIg prophylaxis in fulminant and selected chronic HBV-infected liver graft recipients

Strategies using lamivudine and hepatitis B immunoglobulins (HBIg) for prevention of hepatitis B virus (HBV) reinfection after liver transplantation (LT) are expensive since life-long treatment is needed. We evaluated the possibility to obtain protective hepatitis B surface antigen (HBsAg) antibody (anti-HBs) titers after LT and to discontinue HBIg prophylaxis after a reinforced course of vaccination against HBV using an experimental adjuvant HBsAg / AS04 vaccine (GlaxoSmithKline Biologicals [GSK], Rixensart, Belgium) in patients transplanted for hepatitis B. Fifteen LT patients on stable low-level immunosuppression were vaccinated with a double dose of the vaccine at 0, 1, 2, 6, and 12 months: 5 patients were transplanted for nonviral diseases and 10 patients were transplanted for HBV on HBIg monotherapy. HBIg were continued during baseline vaccination (0, 1, and 2 months) and when anti-HBs titers determined every 6 weeks dropped below 150 IU/L. Overall follow-up was 18 months. Sustained long-term response to vaccination was defined as anti-HBs titers >500 IU/L without further need for HBIg administration during a follow-up period of at least 12 months. Overall sustained response to vaccination was 53% (8 / 15 patients); 80% (4 / 5 patients) in the nonviral disease group and 40% (4 / 10 patients) in the HBV group (2 /2 fulminant and 2/8 chronically infected patients) developed a sustained long-term response and were completely free of HBIg at the end of the 18-month follow-up. No HBV recurrence, rejection episodes, or side effects occurred during the follow-up. In conclusion, protective anti-HBs titers were obtained in a substantial number of LT patients following a reinforced course of HBV vaccination with vaccines containing new immunostimulating adjuvants. Vaccination seems well tolerated and safe and allows long-term discontinuation of HBIg.

Safety and immunogenicity of the American Academy of Pediatrics--recommended sequential pneumococcal conjugate and polysaccharide vaccine schedule in pediatric solid organ transplant recipients

OBJECTIVE

Solid organ transplant recipients are at increased risk for invasive pneumococcal disease. The American Academy of Pediatrics recommends immunization with sequential pneumococcal vaccines for this group; however, data are lacking. Accordingly, this study was designed to evaluate the safety and immunogenicity of the recommended regimen.

METHODS

Pediatric solid organ transplant recipients (n = 25) between 2 and 18 years of age who had not previously received 7-valent conjugate pneumococcal vaccine (PCV7) were enrolled. These patients received 2 doses of the PCV7 and a single dose of the 23-valent polysaccharide pneumococcal vaccine (23V). Each vaccine dose was given 2 months apart. Healthy age-matched controls (n = 23) were enrolled for comparison. Controls received a single dose of PCV7 followed 2 months later by a single dose of 23V. Antibody concentrations to serotypes 1, 4, 5, 6B, 9V, 14, 18C, 19F, and 23F were measured by enzyme-linked immunosorbent assay prevaccination, 2 months after each vaccine dose and 5 to 7 months after 23V. Local and systemic reactions to each vaccine dose were recorded.

RESULTS

Systemic and injection-site reactions were comparable between the 2 groups. Significant rises in serotype-specific pneumococcal antibody geometric mean concentrations from prevaccination levels were observed in both groups; however, final antibody responses to serotypes 1, 4, 9V, 14, 18C, 19F, and 23F were significantly lower in solid organ transplant recipients compared with the control group. Antibody concentrations did not increase significantly among solid organ transplant patients after the second dose of PCV7. No additional increase in PCV7-associated serotype-specific antibody levels was observed after the 23V dose in both groups. Heart transplant recipients had lower antibody responses compared with liver transplant recipients.

CONCLUSIONS

Although the pneumococcal vaccine regimen was safe and immunogenic among pediatric solid organ transplant recipients, the patients did not seem to benefit from the second dose of PCV7 or from the 23V dose given 2 months later. Additional studies are needed to determine the number of PCV7 doses and the interval between PCV7 and 23V to induce optimal responses.

Influenza vaccine antibody responses in lung transplant recipients

CONTEXT

Lung transplant recipients are at high risk of morbidity and mortality from influenza infection because of altered lung physiology and immunosuppression. Annual influenza immunization is recommended, but the ability to mount an antibody response may be limited by immunosuppressant medications.

OBJECTIVE

To compare the antibody response rate to influenza vaccine in lung transplant recipients to healthy controls.

DESIGN

Open label study.

SETTING

Lung transplant clinic and General Clinical Research Center at a university hospital.

SUBJECTS

Sixty-eight single and bilateral lung transplant recipients and 35 healthy controls were enrolled in October and November 2002.

METHODS

Each individual underwent blood sampling before receiving the 2002-2003 influenza vaccine and 4 weeks later. Influenza antibody concentrations were measured by hemagglutination inhibition assay. Vaccine response rates (antibody concentration >40 hemagglutination units and at least 4-fold increase in antibody concentration) were compared using chi2. The influence of specific immunosuppressants on vaccine response was compared.

RESULTS

The influenza vaccine response rate for lung transplant recipients was 29/68 (43%) and 22/35 (63%) for the healthy individuals (P < .05; chi2). Among the recipients, mycophenolate mofetil was associated with poorer influenza vaccine antibody response (> 40 hemagglutination units) (62% vs 91%; P = .01), whereas sirolimus (91% vs 63%; P = .02) was associated with better influenza antibody response compared to those not taking mycophenolate mofetil or sirolimus, respectively.

CONCLUSION

Lung transplant recipients had lower influenza vaccine response rates than healthy individuals. Influenza vaccine antibody response is influenced by concomitant administration of mycophenolate mofetil or sirolimus. Future studies should measure protection from influenza infection conferred by immunization and alternative vaccination strategies.

The potential of GM-CSF to improve resistance against infections in organ transplantation

Immunosuppressed patients retain transplants but become more susceptible to opportunistic infections, which is a major complication in organ transplantation. Life-long immunosuppression for such patients could be reduced by creating immune tolerance, although this might be associated with an increased risk for infections and malignancies. An alternative therapeutic concept could consist of boosting the innate immune response against infections while continuing to suppress the adaptive immune response to prevent graft rejection. We propose granulocyte-macrophage colony-stimulating factor (GM-CSF) as a novel candidate to achieve this goal, based on recent studies in which beneficial effects were demonstrated in immunosuppressed mice with skin allografts and in dexamethasone-suppressed blood from healthy volunteers and blood from liver transplant recipients undergoing immunosuppressive therapy. Such data suggest that GM-CSF or other endogenous factors with similar properties should be examined in clinical trials.

Tolerance of liver transplant patients to strenuous physical activity in high-altitude

Physical functioning is improved after liver transplantation but studies comparing liver transplant recipients with normal healthy people are lacking. How liver (and other organ) transplant recipients tolerate strenuous physical activities is unknown. There are no data on the tolerance of transplant patients at high altitude. Six liver transplant subjects were selected to participate in a trek up Mount Kilimanjaro 5895 m, Tanzania. Physical performance and susceptibility to acute mountain sickness were prospectively compared with fifteen control subjects with similar profiles and matched for age and body mass index. The Borg-scale (a rating of perceived exertion) and cardiopulmonary parameters at rest were prospectively compared with six control subjects also matched for gender and VO2max. Immunosuppression in transplant subjects was based on tacrolimus. No difference was seen in physical performance, Borg-scales and acute mountain sickness scores between transplant and control subjects. Eight-three percent of transplant subjects and 84.6% of control subjects reached the summit (p=0.7). Oxygen saturation decreased whereas arterial blood pressure and heart rate increased with altitude in both groups. The only difference was the development of arterial hypertension in transplant subjects at 3950 m (p=0.036). Selected and well-prepared liver transplant recipients can perform strenuous physical activities and tolerate exposure to high altitude similar to normal healthy people.

Immunization of children after solid organ transplantation

The array of immunizations commonly used in childhood has risen in an attempt to prevent many of the potentially serious infections of infancy and childhood. In this article, the authors provide rational guidelines for vaccination of these children. The authors briefly review the susceptibilities caused by immunosuppression in these patients, discuss the problems with various immunizations, and make individual recommendations regarding the use of each vaccine. Most recommendations are based on inferences from populations that may not be directly comparable to the transplantation population (patients with HIV or cancer or patients who have undergone bone marrow transplant), from case reports, and from small series of patients. The best recommendations ultimately must await the results of controlled trials of immunization.

Immunization with an adjuvant hepatitis B vaccine after liver transplantation for hepatitis B-related disease

Patients who undergo transplantation for hepatitis B virus (HBV)-related diseases are treated indefinitely with hepatitis B hyperimmunoglobulin (HBIG) to prevent endogenous HBV reinfection of the graft. Active immunization with standard hepatitis B vaccines in these patients has recently been reported with conflicting results. Two groups of 10 liver transplant recipients on continuous HBIG substitution who were hepatitis B surface antigen (HBsAg) positive and HBV DNA negative before transplantation were immunized in a phase I study with different concentrations of hepatitis B s antigen formulated with the new adjuvants 3-deacylated monophosphoryl lipid A (MPL) and Quillaja saponaria (QS21) (group I/vaccine A: 20 microg HBsAg, 50 microg MPL, 50 microg QS21; group II/vaccine B: 100 microg HBsAg, 100 microg MPL, 100 microg QS21). Participants remained on HBIG prophylaxis and were vaccinated at weeks 0, 2, 4, 16, and 18. They received 3 additional doses of vaccine B at bimonthly intervals if they did not reach an antibody titer against hepatitis B surface antigen (anti-HBs) greater than 500 IU/L. Sixteen (8 in each group) of 20 patients (80%) responded (group I: median, 7,293 IU/L; range, 721-45,811 IU/L anti-HBs; group II: median, 44,549 IU/L; range, 900-83,121 IU/L anti-HBs) and discontinued HBIG. They were followed up for a median of 13.5 months (range, 6-22 months). The vaccine was well tolerated. In conclusion, most patients immunized with the new vaccine can stop HBIG immunoprophylaxis for a substantial, yet to be determined period of time.

Immunization with an adjuvant hepatitis B vaccine after liver transplantation for hepatitis B-related disease

Patients who undergo transplantation for hepatitis B virus (HBV)-related diseases are treated indefinitely with hepatitis B hyperimmunoglobulin (HBIG) to prevent endogenous HBV reinfection of the graft. Active immunization with standard hepatitis B vaccines in these patients has recently been reported with conflicting results. Two groups of 10 liver transplant recipients on continuous HBIG substitution who were hepatitis B surface antigen (HBsAg) positive and HBV DNA negative before transplantation were immunized in a phase I study with different concentrations of hepatitis B s antigen formulated with the new adjuvants 3-deacylated monophosphoryl lipid A (MPL) and Quillaja saponaria (QS21) (group I/vaccine A: 20 microg HBsAg, 50 microg MPL, 50 microg QS21; group II/vaccine B: 100 microg HBsAg, 100 microg MPL, 100 microg QS21). Participants remained on HBIG prophylaxis and were vaccinated at weeks 0, 2, 4, 16, and 18. They received 3 additional doses of vaccine B at bimonthly intervals if they did not reach an antibody titer against hepatitis B surface antigen (anti-HBs) greater than 500 IU/L. Sixteen (8 in each group) of 20 patients (80%) responded (group I: median, 7,293 IU/L; range, 721-45,811 IU/L anti-HBs; group II: median, 44,549 IU/L; range, 900-83,121 IU/L anti-HBs) and discontinued HBIG. They were followed up for a median of 13.5 months (range, 6-22 months). The vaccine was well tolerated. In conclusion, most patients immunized with the new vaccine can stop HBIG immunoprophylaxis for a substantial, yet to be determined period of time.

Tetanus antitoxin seroprevalence in patients with Behçet's disease

Anti-tetanus antibody status was evaluated by enzyme-linked immunosorbent assay in 82 patients with Behçet's disease and 79 healthy individuals. 76 patients with Behçet's disease (92.7%) and 74 healthy controls (93.7%) had protective antibody titres against tetanus, with geometric mean levels of 1.0194 +/- 1.2755 and 1.3899 +/- 1.6533 IU/ml, respectively. The difference between the 2 groups was not statistically significant. There was a significant inverse correlation between antitoxin titres and age in patient and control groups. These findings imply that patients with Behçet's disease have intact overall immunity against tetanus.

Smallpox and live-virus vaccination in transplant recipients

Recent bioterrorism raises the specter of reemergence of smallpox as a clinical entity. The mortality of variola major infection ('typical smallpox') was approximately 30% in past outbreaks. Programs for smallpox immunization for healthcare workers have been proposed. Atypical forms of smallpox presenting with flat or hemorrhagic skin lesions are most common in individuals with immune deficits with historic mortality approaching 100%. Smallpox vaccination, even after exposure, is highly effective. Smallpox vaccine contains a highly immunogenic live virus, vaccinia. Few data exist for the impact of variola or safety of vaccinia in immunocompromised hosts. Both disseminated infection by vaccinia and person-to-person spread after vaccination are uncommon. When it occurs, secondary vaccinia has usually affected individuals with pre-existing skin conditions (atopic dermatitis or eczema) or with other underlying immune deficits. Historically, disseminated vaccinia infection was uncommon but often fatal even in the absence of the most severe form of disease, "progressive vaccinia". Some responded to vaccinia immune globulin. Smallpox exposure would be likely to cause significant mortality among immunocompromised hosts. In the absence of documented smallpox exposures, immunocompromised hosts should not be vaccinated against smallpox. Planning for bioterrorist events must include consideration of uniquely susceptible hosts.

Vaccinations for adult solid-organ transplant recipients: current recommendations and protocols

Recipients of solid-organ transplantation are at risk of severe infections due to their life-long immunosuppression. Despite emerging evidence that vaccinations are safe and effective among immunosuppressed patients, most vaccines are still underutilized in these patients. The efficacy, safety, and protocols of several vaccines in this patient population are poorly understood. Timing of vaccination appears to be critical because response to vaccinations is decreased in patients with end-stage organ disease and in the first 6 months after transplantation. For these reasons, the primary immunizations should be given before transplantation, as early as possible during the course of disease. Vaccination strategy should include vaccination of household contacts and health care workers at transplant centers unless contraindicated. No conclusive data are available on the use of immunoadjuvants and screening for protective titers. Most vaccines appear to be safe in solid-organ transplantation recipients, but live vaccines should be avoided until further studies are available. The risk of rejection appears minimal. Recommended vaccines include pneumovax, hepatitis A and B, influenza, and tetanus-diphtheria. We outline specific protocols and recommendations in this particular patient population. Specific contraindications exist for other vaccines, such as yellow fever, oral polio vaccine, bacillus Calmette-Guerin, and vaccinia. We conclude that solid-organ recipients will benefit from consistent immunization practices. Further studies are recommended to improve established protocols in this patient population.

[Vaccinations and solid-organ transplantation: review and recommendations]

Pediatric solid-organ transplant recipients are at high risk for various infectious diseases. Many children are not fully vaccinated before transplantation. To reduce the risk of morbidity and mortality from vaccine-preventable disease, physicians treating pediatric solid-organ transplant recipients should monitor the immunization status of these patients. Consensus on the most appropriate immunization schedule for solid-organ transplant recipients is lacking. Therefore, we provide a review of the currently available data on immunization safety and efficacy and describe strategies to avoid vaccine-preventable diseases in pediatric solid-organ transplant recipients.

Successful hepatitis B vaccination in patients who underwent transplantation for hepatitis B virus-related cirrhosis: preliminary results

Long-term hepatitis B immunoglobulin (HBIg) prophylaxis prevents endogenous hepatitis B virus (HBV) reinfection in the majority of liver transplant recipients. Active hepatitis B vaccination after orthotopic liver transplantation (OLT) in these patients has produced conflicting results to date. On this study, patients who remained hepatitis B surface antigen (HBsAg) negative with passive immunization after OLT for HBV cirrhosis were actively immunized using recombinant HBV antigen (Engerix), together with a novel adjuvant system (monophosphoryl lipid A and a natural saponine molecule). This led to a sustained antibody response to HBsAg (>500 IU/L) in 5 of 10 patients. This antibody response prevented reinfection and allowed termination of prophylactic HBIg substitution for more than 12 months in these patients.