Varicella vaccination in children with steroid-sensitive nephrotic syndrome

Vaccines and nephrotic syndrome: efficacy and safety

Vaccines represent the most important medical evolution in the last two centuries allowing prevention and formally eradication of a wide number of infectious diseases. Safety and effectiveness are main issues that still require an open discussion. A few clinical reports described a critical temporal relationship between vaccination and acute nephrotic syndrome, indirectly suggesting an association. For this review, the literature was reviewed to identify articles reporting associations of nephrotic syndrome with vaccines against a vast array of infectious diseases (including bacteria, virus and Sars-Cov-2). As specific aims, we evaluated effectiveness and safety in terms of occurrence of either "de novo" nephrotic syndrome in health subjects or "relapse" in those already affected by the disease. In total, 377 articles were found; 166 duplicates and 71 non-full text, animal studies or non-English language were removed. After excluding another 50 articles not containing relevant data on generic side effects or on relapses or new onset nephrotic syndrome, 90 articles met the search criteria. Overall, studies reported the effect of vaccines in 1015 patients, plus 4 nationwide epidemiologic investigations. Limited experience on vaccination of NS patients with measles, mumps, and rubella live attenuated vaccines does not allow any definitive conclusion on their safeness. VZV has been administered more frequently without side effects. Vaccines utilizing virus inactivated, recombinant, and toxoid can be utilized without risks in NS. Vaccines for influenza reduce the risk of infections during the pandemic and are associated with reduced risk of relapse of NS typically induced by the infection. Vaccines for SARS-CoV-2 (all kinds) offer a concrete approach to reduce the pandemic. "De novo" NS or recurrence are very rare and respond to common therapies.

Is influenza vaccination associated with nephrotic syndrome relapse in children? A multicenter prospective study

BACKGROUND

Prospective research of children receiving heterogeneous vaccines has shown that immunization is not associated with pediatric idiopathic nephrotic syndrome (NS) relapses. However, prospective data concentrating only on influenza (flu) virus vaccines are not available.

METHODS

This multicenter prospective study was conducted in children with NS who received inactivated flu vaccines from June 2017 to July 2018. The day of flu vaccination was defined as day 0, and the period between prevaccination and postvaccination days was defined as - X to + Y (period from day - 180 to 0 as the precontrolled period). The primary outcome was the NS relapse rate from day 0 to + 30 as a direct association with vaccination compared with those in the precontrolled period. Exacerbation was defined as children experiencing more NS relapses after vaccination compared with those in the precontrolled period, or children starting any new immunosuppressants due to NS relapse after vaccination.

RESULTS

Sixty-three children were included. Relapse rates were not significantly different between the precontrolled period and 0 to + 30 periods (0.38 vs. 0.19 times/person-year, p = 0.95). Although the exacerbation rate during the 0 to + 180 period in children without NS relapse in the precontrolled period was very low (4/54 [7.4 %]), children with at least one NS relapse in the precontrolled period showed a remarkable increase in the rate (4/9 [44.4%]; p = 0.01).

CONCLUSIONS

Flu vaccination did not significantly precipitate the direct relapse of NS in children. However, it might increase the disease activity in children with at least one NS relapse within a half year before vaccination. A higher resolution version of the Graphical abstract is available as Supplementary information.

Influenza virus vaccination in pediatric nephrotic syndrome significantly reduces rate of relapse and influenza virus infection as assessed in a nationwide survey

Although vaccination may precipitate relapses of nephrotic syndrome (NS) in children with idiopathic NS, no data are available regarding NS activity regarding influenza (flu) virus infections and NS relapses after receiving inactivated flu vaccines. We conducted a nationwide study of children aged 6 months to 15 years with idiopathic NS to assess the relationship between NS relapse, flu vaccination, and flu infections. We used a multivariate Poisson regression model (MPRM) to calculate the risk ratio (RR) for flu infection and for NS relapse in children with and without flu vaccination. Data of 306 children were assessed. The MPRM in all 306 children showed a significantly lower RR for flu infection (RR: 0.21, 95% confidence interval CI 0.11-0.38) and for NS relapse (RR: 0.22, 95% CI 0.14-0.35) in children receiving flu vaccination compared with unvaccinated children. In an additional MPRM only among 102 children receiving flu vaccination, they had a significantly lower risk for NS relapse during the post-vaccination period (RR: 0.31. 95% CI 017-0.56) compared with the pre-vaccination period. Although our study was observational, based on the favorable results of flu vaccinations regarding flu infections and NS relapse, the vaccine may be recommended for children with NS.

Steroid Sensitive Nephrotic Syndrome: Revised Guidelines

Justification

Steroid sensitive nephrotic syndrome (SSNS) is one of the most common chronic kidney diseases in children. These guidelines update the existing Indian Society of Pediatric Nephrology recommendations on its management.

Objective

To frame revised guidelines on diagnosis, evaluation, management and supportive care of patients with the illness.

Process

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by review of literature and evaluation of evidence by experts in two face-to-face meetings.

Recommendations

The initial statements provide advice for evaluation at onset and follow up and indications for kidney biopsy. Subsequent statements provide recommendations for management of the first episode of illness and of disease relapses. Recommendations on the use of immunosuppressive strategies in patients with frequent relapses and steroid dependence are accompanied by suggestions for step-wise approach and plan of monitoring. Guidance is also provided regarding the management of common complications including edema, hypovolemia and serious infections. Advice on immunization and transition of care is given. The revised guideline is intended to improve the management and outcomes of patients with SSNS, and provide directions for future research.

Influenza virus vaccination in children with nephrotic syndrome: insignificant risk of relapse

Background

Immunization with various vaccines is considered desirable for children with idiopathic nephrotic syndrome (NS) because of their high risk of severe infections. Vaccinations may precipitate relapses of NS, but there is no available data regarding inactivated influenza (flu) virus vaccines.

Methods

We retrospectively reviewed the medical records of children with NS who had received flu vaccines between 2002 and 2015. The day of flu vaccination was defined as day 0, and the period between the pre-vaccination and the post-vaccination days was defined as − X to + Y. The risk ratios and their 95% confidence intervals for NS relapse rate were estimated by generalized estimating equation (GEE) Poisson regression.

Results

A total of 104 pediatric patients received 208 flu vaccines. The mean age at onset of NS was at 4.85 ± 3.87 years old. There were 261 NS relapses between days − 180 and + 180. Compared with the relapse rate in the − 180 to 0 interval (1.19 times/person-year), those in 0 to + 30 (1.23), + 31 to + 60 (1.58), + 61 to + 90 (1.41), + 91 to + 120 (1.41), and + 121 to + 180 (1.32) days groups were slightly increased, but without significance. Multivariate analysis using GEE Poisson regression also showed no significant increase in relapse rate in each day group compared with days − 180 to 0. Risk ratios for NS relapse were significantly higher in children who were treated with steroids at the first vaccination.

Conclusions

Our results suggest that flu vaccines should not be avoided in children with NS based on the potential for NS relapses.

Electronic supplementary material

The online version of this article (10.1007/s10157-020-01930-8) contains supplementary material, which is available to authorized users.

[Vaccine recommendations for children with idiopathic nephrotic syndrome]

The specific treatment of idiopathic nephrotic syndrome is based on corticosteroid therapy and/or steroid-sparing immunosuppressive agents in children who are steroid-dependant or frequent relapsers (60-70 %). Patients have an increased infectious risk not only related to the disease during relapses (hypogammaglobulinemia and urinary leakage of opsonins) but also to treatments (corticosteroids or immunosuppressive agents) in period of remission. Vaccination is therefore particularly recommended in these patients. Potential vaccine risks are ineffectiveness, induction of vaccine disease and relapse of idiopathic nephrotic syndrome. Only live vaccines expose to the risk of vaccine disease: they are in general contra-indicated under immunosuppressive treatment. The immunogenicity of inactivated vaccines is reduced but persists. The immunogenic stimulus of vaccination may in theory trigger a relapse of the nephrotic syndrome. Nevertheless, this risk is low in the literature, and even absent in some studies. The benefit-risk ratio is therefore in favor of vaccination with respect to the vaccination schedule for inactivated vaccines, with wide vaccination against pneumococcus and influenza annually. Depending on the context and after expert advice, immunization with live vaccines could be discussed if residual doses/levels of immunosuppressive treatments are moderate and immunity preserved.

Influenza vaccination among children with idiopathic nephrotic syndrome: an investigation of practices

Background

Annual influenza vaccination is recommended for all children with idiopathic nephrotic syndrome (INS) in France. Consequently, the Social Security automatically sends prescriptions to all patients suffering from a chronic disease. The aim of this study was to evaluate the follow-up to these recommendations.

Methods

We conducted a monocentric retrospective investigation of practices. We included all children with steroid-sensitive INS in remission who attended our clinics from January 1st 2015 to January 1st 2017, resided in France and had a valid phone number. Data were collected from May 2017 to June 2017 through a phone interview and review of clinical charts.

Results

75 patients met the inclusion criteria. The parents of 57 children could be reached by phone and agreed to participate to the survey. 35/57 (61.4%) declared having received a prescription during the 2016–2017 campaign. Only 14 children (24.6%) were vaccinated. 17/43 (39.5%) parents of unvaccinated children had concerns about the safety of the vaccine, 16/43 (37.2%) were not aware of the recommendations, 5/43 (11.6%) had been recommended by their physician not to vaccinate their child, 3/43 (7%) forgot to have them vaccinated and 2/43 (4.6%) reported no reason. 13/43 (30%) unvaccinated children presented a relapse during the flu season - 2/13 during an influenza-like illness - whereas 1/14 (7%) immunized children presented a relapse during the six months of post-vaccination follow-up. Relapse rates were not increased in vaccinated children compared to unvaccinated children (p = 0.15), nor in the 6 months following vaccination compared to the 6 months prior (1/14 vs 5/14, p = 0.20).

Conclusions

1) < 2/3 patients were properly prescribed the recommended yearly influenza vaccination at our center 2) only 1/4 were vaccinated and most of their parents were misinformed. Physicians must be aware of this and should make every effort to better inform their patients on the risks of flu illness and the benefits and safety of the vaccination.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1240-2) contains supplementary material, which is available to authorized users.

Varicella infection in the Middle East: Prevalence, complications, and vaccination

Varicella (chickenpox) is the primary infection of varicella-zoster virus (VZV), it is a mild self-limiting infection, but it is also highly contagious and can cause severe complications among high-risk group of individuals. It is usually a childhood infection providing lifelong immunity, but adults without varicella history are also susceptible to infection. High-risk group of individuals is more likely to develop serious complications. Varicella vaccine was introduced to protect this group of individuals and to prevent epidemic spread of VZV infection in a community. Thus, it was added to the recommended vaccination schedules for children in most developed countries. This review aimed to outline varicella status, seroprevalence, complications, and vaccination in the Middle East region. Based on our findings, children were the most affected age group, but there are also adult cases due to high number of expatriates, especially in Gulf Cooperation Council countries. Central nervous system involvements and skin diseases followed by varicella pneumonia were the most varicella-associated complications. Varicella vaccine was introduced in most Middle East countries, either mandatory by the Ministries of Health or optional in the private clinics. Few numbers of studies have reported an obvious reduction in varicella prevalence, hospitalizations, and deaths in the Middle East following varicella vaccination. A basic database about varicella infection before the initiation and implementation of a vaccination policy is essential to determine the target group of individuals. As far as our knowledge, this is the first review about varicella infection in the Middle East.

The Italian Society for Pediatric Nephrology (SINePe) consensus document on the management of nephrotic syndrome in children: Part I - Diagnosis and treatment of the first episode and the first relapse

This consensus document is aimed at providing an updated, multidisciplinary overview on the diagnosis and treatment of pediatric nephrotic syndrome (NS) at first presentation. It is the first consensus document of its kind to be produced by all the pediatric nephrology centres in Italy, in line with what is already present in other countries such as France, Germany and the USA. It is based on the current knowledge surrounding the symptomatic and steroid treatment of NS, with a view to providing the basis for a separate consensus document on the treatment of relapses. NS is one of the most common pediatric glomerular diseases, with an incidence of around 2-7 cases per 100000 children per year. Corticosteroids are the mainstay of treatment, but the optimal therapeutic regimen for managing childhood idiopathic NS is still under debate. In Italy, shared treatment guidelines were lacking and, consequently, the choice of steroid regimen was based on the clinical expertise of each individual unit. On the basis of the 2015 Cochrane systematic review, KDIGO Guidelines and more recent data from the literature, this working group, with the contribution of all the pediatric nephrology centres in Italy and on the behalf of the Italian Society of Pediatric Nephrology, has produced a shared steroid protocol that will be useful for National Health System hospitals and pediatricians. Investigations at initial presentation and the principal causes of NS to be screened are suggested. In the early phase of the disease, symptomatic treatment is also important as many severe complications can occur which are either directly related to the pathophysiology of the underlying NS or to the steroid treatment itself. To date, very few studies have been published on the prophylaxis and treatment of these early complications, while recommendations are either lacking or conflicting. This consensus provides indications for the prevention, early recognition and treatment of these complications (management of edema and hypovolemia, therapy and prophylaxis of infections and thromboembolic events). Finally, recommendations about the clinical definition of steroid resistance and its initial diagnostic management, as well as indications for renal biopsy are provided.

Vaccinations in children on immunosuppressive medications for renal disease

Renal diseases are often treated with immunosuppressive medications, placing patients at risk of infections, some of which are vaccine-preventable. However, in such patients vaccinations may be delayed or disregarded due to complications of the underlying disease process and challenges in its management. The decision to administer vaccines to immunosuppressed children is a risk-benefit balance as such children may have a qualitatively diminished immunological response or develop diseases caused by the vaccine pathogen. Vaccination may cause a flare-up of disease activity or provocation of graft rejection in renal transplant recipients. Moreover, it cannot be assumed that a given antibody level provides the same protection in immunosupressed children as in healthy ones. We have evaluated the safety and efficacy of licensed vaccines in children on immunosuppressive therapy and in renal transplant recipients. The limited evidence available suggests that vaccines are most effective if given early, ideally before the requirement for immunosuppressive therapy, which may require administration of accelerated vaccine courses. Once treatment with immunosuppressive drugs is started, inactivated vaccines are usually considered to be safe when the disease is quiescent, but supplemental doses may be required. In the majority of cases, live vaccines are to be avoided. All vaccines are generally contraindicated within 3-6 months of a renal transplant.

The non-immunosuppressive management of childhood nephrotic syndrome

Idiopathic nephrotic syndrome (INS) is one of the most common renal diseases found in the paediatric population and is associated with significant complications, including infection and thrombosis. A high proportion of children enter sustained remission before adulthood, and therapy must therefore mitigate the childhood complications, while minimising the long-term risk to health. Here we address the main complications of INS and summarise the available evidence and guidance to aid the clinician in determining the appropriate treatment for children with INS under their care. Additionally, we highlight areas where no consensus regarding appropriate management has been reached. In this review, we detail the reasons why routine prophylactic antimicrobial and antithrombotic therapy are not warranted in INS and emphasise the conservative management of oedema. When pharmacological intervention is required for the treatment of oedema, we provide guidance to aid the clinician in determining the appropriate therapy. Additionally, we discuss obesity and growth, fracture risk, dyslipidaemia and thyroid dysfunction associated with INS. Where appropriate, we describe how recent developments in research have identified potential novel therapeutic targets.

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND

The prevention of varicella (chickenpox) using live attenuated varicella vaccines has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States and Australia. Many countries do not routinely immunise children against varicella and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP).

OBJECTIVES

To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1966 to March week 1, 2014), EMBASE (January 1990 to March 2014) and LILACS (1982 to March 2014). We searched for unpublished trials registered on the clinicaltrials.gov and WHO ICTRP websites.

SELECTION CRITERIA

RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse events following vaccination.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data using Review Manager software.

MAIN RESULTS

We identified three trials involving 110 healthy children who were siblings of household contacts. The included trials varied in study quality, vaccine used, length of follow-up and outcomes measured and, as such, were not suitable for meta-analysis. We identified high or unclear risk of bias in two of the three included studies. Overall, 13 out of 56 vaccine recipients (23%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with fewer than 50 skin lesions). In the three trials, most participants received PEP within three days following exposure; too few participants were vaccinated four to five days post-exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included trial reported on adverse events following immunisation.

AUTHORS' CONCLUSIONS

These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. We identified no RCTs for adolescents or adults. Safety was not adequately addressed.

Hepatitis B virus vaccination in children with steroid sensitive nephrotic syndrome: immunogenicity and safety?

We investigated the efficacy and safety of Hepatitis B vaccine (HBVac) in steroid sensitive nephrotic syndrome (SSNS) children. 41 patients with SSNS and 30 controls were vaccinated with HBVac(Engerix B(®)). Patients were divided into 3 subgroups:full dose steroid users, alternate-day steroid users and steroid non-users. Seroconversion rate was lower in steroid users than non-users at the 6th(p=0.015) and 12th(p=0.036) months. Antibody to Hepatitis B surface antigen(HBsAb) titers were significantly different between subgroups and controls at the 15th month. However, HBsAb and response rates were not different between subgroups at the 12th and 15th months (p>0.05). Five patients were unresponsive to HBVac. Relapse rates after the vaccination were higher than those in the prevaccination period (p=0.002). HBVac is less effective in producing immune response in SSNS children with steroid therapy. HBVac may trigger relapse in some patients. We recommend HBVac to SSNS children with low dose steroid therapy or after steroids are discontinued.

Complications of nephrotic syndrome

Nephrotic syndrome (NS) is one of the most common glomerular diseases that affect children. Renal histology reveals the presence of minimal change nephrotic syndrome (MCNS) in more than 80% of these patients. Most patients with MCNS have favorable outcomes without complications. However, a few of these children have lesions of focal segmental glomerulosclerosis, suffer from severe and prolonged proteinuria, and are at high risk for complications. Complications of NS are divided into two categories: disease-associated and drug-related complications. Disease-associated complications include infections (e.g., peritonitis, sepsis, cellulitis, and chicken pox), thromboembolism (e.g., venous thromboembolism and pulmonary embolism), hypovolemic crisis (e.g., abdominal pain, tachycardia, and hypotension), cardiovascular problems (e.g., hyperlipidemia), acute renal failure, anemia, and others (e.g., hypothyroidism, hypocalcemia, bone disease, and intussusception). The main pathomechanism of disease-associated complications originates from the large loss of plasma proteins in the urine of nephrotic children. The majority of children with MCNS who respond to treatment with corticosteroids or cytotoxic agents have smaller and milder complications than those with steroid-resistant NS. Corticosteroids, alkylating agents, cyclosporin A, and mycophenolate mofetil have often been used to treat NS, and these drugs have treatment-related complications. Early detection and appropriate treatment of these complications will improve outcomes for patients with NS.

Pharmacotherapeutic review and update of idiopathic nephrotic syndrome in children

AIM OF THE REVIEW

The therapeutic management of pediatric idiopathic nephrotic syndrome is still a challenge due to the large number of potentially effective pharmacological alternatives and the insufficient scientific evidence available. A bibliographic review was performed in order to identify the available pharmacological alternatives, as well as their place in therapy, and to analyze whether the treatment algorithm developed by the pediatric nephrology department of our hospital is consistent with the evidence published to date.

METHOD

A literature search was carried out on MEDLINE, through PubMed, using the medical subject heading (MeSH) nephrotic syndrome. The search was limited to review papers, meta-analyses, clinical practice guidelines, and randomized controlled trials performed on pediatric populations up to September 2009.

RESULTS

The treatment algorithm established in our hospital is consistent with the evidence available. Prednisone constitutes the first line treatment with evidence level Ia. When corticosteroids do not achieve remission, there are other therapeutic options that are not clearly positioned yet and further studies that provide more information on their comparative efficacy and safety are needed. These alternative therapeutic options are cyclosporine, mycophenolate mofetil, levamisol, cyclophosphamide and methylprednisolone, as independent strategies or as part of "Mendoza Protocol", tacrolimus and rituximab. Their sequence of introduction in the therapeutic scheme of NS is classified as evidence level IV and grade D recommendation.

CONCLUSION

The wide range of options available for the pharmacotherapeutic management of NS and the lack of evidence about the comparative efficacy and safety of the different therapeutic strategies, make its positioning rather difficult. Therefore each hospital needs to draw up protocols based not only on the small amount of evidence available, but also on the authorized indications, availability of the drugs, clinical experience, associated costs, and patient preferences with regard to the duration of treatment, incidence and type of adverse effects. Development of new randomized controlled trials should be encouraged and setting up national plans for the treatment of this pathology might be a good approach for this problem.

Management of childhood onset nephrotic syndrome

The therapeutic approach to childhood nephrotic syndrome is based on a series of studies that began with an international collaborative effort sponsored by the International Study of Kidney Disease in Children in 1967. The characteristics of children presenting with nephrotic syndrome have changed over recent decades with greater frequency of the challenging condition focal segmental glomerulosclerosis and a greater prevalence of obesity and diabetes mellitus, which may be resistant to glucocorticoids in the former and exacerbated by long-term glucocorticoid therapy in the latter 2 conditions. The Children's Nephrotic Syndrome Consensus Conference was formed to systematically review the published literature and generate a children's primary nephrotic syndrome guideline for use in educational, therapeutic, and research venues.

Vaccines for post-exposure prophylaxis against varicella (chickenpox) in children and adults

BACKGROUND

Live attenuated varicella vaccines for the prevention of varicella (chickenpox) has been demonstrated both in randomised controlled trials (RCTs) and in population-based immunisation programmes in countries such as the United States. However, many countries do not routinely immunise children against varicella, and exposures continue to occur. Although the disease is often mild, complications such as secondary bacterial infection, pneumonitis and encephalitis occur in about 1% of cases, usually leading to hospitalisation. The use of varicella vaccine in persons who have recently been exposed to the varicella zoster virus has been studied as a form of post-exposure prophylaxis (PEP).

OBJECTIVES

To assess the efficacy and safety of vaccines for use as PEP for the prevention of varicella in children and adults.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008, Issue 1); MEDLINE (1966 to February 2008); and EMBASE (January 1990 to February 2008).

SELECTION CRITERIA

RCTs and quasi-RCTs of varicella vaccine for PEP compared with placebo or no intervention. The outcome measures were efficacy in prevention of clinical cases and/or laboratory-confirmed clinical cases and adverse effects following vaccination.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and analysed data using Review Manager software.

MAIN RESULTS

Three studies involving 110 healthy children who were siblings of household contacts were identified as suitable for inclusion. The studies varied in quality, study design, vaccine used, and outcomes measured and, as such, were not suitable for meta-analysis. Overall, 13 out of 56 vaccine recipients (18%) developed varicella compared with 42 out of 54 placebo (or no vaccine) recipients (78%). Of the vaccine recipients who developed varicella, the majority only had mild disease (with less than 50 skin lesions). In the three studies, most subjects received PEP within three days following exposure; too few subjects were vaccinated four to five days post exposure to ascertain the efficacy of vaccine given more than three days after exposure. No included studies reported on adverse events following immunisation.

AUTHORS' CONCLUSIONS

These small trials suggest varicella vaccine administered within three days to children following household contact with a varicella case reduces infection rates and severity of cases. No RCTs for adolescents or adults were identified. However safety was not adequately addressed.

Review of the Varilrix varicella vaccine

Varicella zoster virus causes an acute infection that affects most children globally, but the age of infection can be greater in residents of tropical areas. It has generally been considered a mild disease, although there are accumulating data to show that it can cause significant morbidity and mortality in immunocompetent as well as immunocompromised children and adults. Oka-strain live attenuated varicella vaccines were developed in the 1970s. Varilrix developed by GlaxoSmithKline Biologicals (Rixensart, Belgium), is one of the vaccines produced and marketed in over 80 countries. Similar to the other Oka-strain vaccines, Varilrix is safe, immunogenic and efficacious in both immunocompromised and immunocompetent children and adults.

[Immunisation against varicella]

Two vaccines against varicella are now being licensed in France, both deriving from the Oka strain. Seroconversion has been obtained in almost 100% of the cases after one dose in toddlers and children, and two doses in adolescents and adults. Efficacy has been mainly established from the US experience, where a universal immunisation programme of children aged > 12 months with a catch-up for susceptible adolescents and adults was begun in 1995. The incidence of varicella has decreased by about 85% over all age groups. The safety of the vaccine is good, and most adverse events are represented by fever, reactions at the injection site and varicella-like rashes. For the time being, France has adopted restrictive recommendations for the use of this vaccine because of uncertainties with respect to the duration of protection, a shift of the disease towards older age and the potential increase of the incidence of herpes-zoster.

Seroprevalence of antibodies against varicella-zoster virus and response to the varicella vaccine in pediatric renal transplant patients

The severity of varicella-zoster virus (VZV) in immunocompromised children, especially in those receiving renal transplants, is well known. However, the use of live attenuated virus vaccine in this population is controversial. This study aimed to: (i) assess the immunization status of pediatric renal transplant recipients at our center; (ii) determine the anti-VZV antibody titers in such patients; (iii) evaluate the response to VZV vaccine in seronegative children and in those who present low antibody titers (defined as <500 mAU/mL). Vaccinated children were monitored for adverse effects for 8 wk after vaccination. Fifty patients with a mean age of 13.7 yr (range, 3-17 yr) were enrolled. In 49, blood samples were collected and antibodies were screened using ELISA. Seropositivity to VZV was found in 43 (88%), and antibody titers were >/=500 mAU/mL in 37 (75.5%). Of the 12 children who were eligible for vaccination and had antibody titers <500 mAU/mL, one developed varicella before vaccination, two did not meet the inclusion criteria, and three parents refused the vaccination. In the six vaccinated children, there were no adverse reactions to the vaccine, and four (66.6%) responded with anti-VZV titers >/=500 mAU/mL 6-8 wk after vaccination. In conclusion, after renal transplantation, varicella vaccine is safe with a 66% rate of conversion to high antibody titers.

A review of the varicella vaccine in immunocompromised individuals

BACKGROUND

Individuals with underlying cell-mediated immunodeficiency disorders are at high risk of developing severe, life-threatening illness associated with varicella-zoster virus infection. A live-attenuated varicella vaccine is recommended for routine childhood immunisation in some countries. In healthy children, the vaccine is efficacious and safe but because immunocompromised individuals may be unable to limit replication of live-attenuated vaccine viruses, the varicella vaccine is not recommended for them and there are few exceptions.

OBJECTIVES

The purpose of this paper is to review the published studies addressing the use of the varicella vaccine in people with cell-mediated immunodeficiency disorders.

METHODS

A computerised search on the PubMed database was used to collect the relevant papers published up to March 2003.

RESULTS

The varicella vaccine has been extensively studied in susceptible children with acute lymphoblastic leukaemia in remission, but studies involving individuals with other immunodeficiency disorders are scarce. Some of the current recommendations are based on very few and small studies with short follow-up. Immunocompromised individuals should be given the varicella vaccine only with complete knowledge of their clinical and immunological conditions and after considering the risks of natural infection and vaccination.

Nephrotic syndrome in childhood

Childhood nephrotic syndromes are most commonly caused by one of two idiopathic diseases: minimal-change nephrotic syndrome (MCNS) and focal segmental glomerulosclerosis (FSGS). A third distinct type, membranous nephropathy, is rare in children. Other causes of isolated nephrotic syndrome can be subdivided into two major categories: rare genetic disorders, and secondary diseases associated with drugs, infections, or neoplasia. The cause of idiopathic nephrotic syndrome remains unknown, but evidence suggests it may be a primary T-cell disorder that leads to glomerular podocyte dysfunction. Genetic studies in children with familial nephrotic syndrome have identified mutations in genes that encode important podocyte proteins. Patients with idiopathic nephrotic syndrome are initially treated with corticosteroids. Steroid-responsiveness is of greater prognostic use than renal histology. Several second-line drugs, including alkylating agents, ciclosporin, and levamisole, may be effective for complicated and steroid-unresponsive MCNS and FSGS patients. Nephrotic syndrome is associated with several medical complications, the most severe and potentially fatal being bacterial infections and thromboembolism. Idiopathic nephrotic syndrome is a chronic relapsing disease for most steroid-responsive patients, whereas most children with refractory FSGS ultimately develop end-stage renal disease. Research is being done to further elucidate the disorder's molecular pathogenesis, identify new prognostic indicators, and to develop better approaches to treatment.