Varicella zoster exposure on paediatric wards between 2000 and 2007: safe and effective post-exposure prophylaxis with oral aciclovir

Prevention and Control of Nosocomial Varicella During the United States Varicella Vaccination Program Era

The United States varicella vaccination program has successfully reduced varicella incidence and hospitalizations by ≥90%, consequently reducing the risk of nosocomial exposures. However, patients and healthcare personnel (HCP) continue to introduce varicella zoster virus (VZV) into healthcare settings. Herpes zoster (HZ) is less contagious than varicella, but it can also result in exposures. Unrecognized varicella and HZ may lead to extensive contact investigations, control efforts, and HCP furloughs that result in significant disruption of healthcare activities as well as substantial costs. Robust occupational health and infection prevention programs that ensure healthcare personnel immunity and prompt recognition and isolation of patients with varicella or HZ will lower the risk of VZV transmission and reduce or eliminate the need to furlough exposed HCP and associated costs.

PEPtalk 3: oral aciclovir is equivalent to varicella zoster immunoglobulin as postexposure prophylaxis against chickenpox in children with cancer - results of a multicentre UK evaluation

OBJECTIVE

To compare the occurrence of chickenpox in children with cancer who received varicella immunoglobulin (VZIG) or aciclovir as postexposure prophylaxis (PEP).

DESIGN

Prospective multicentre service evaluation of children with cancer who received either VZIG or aciclovir as PEP following significant exposure to varicella zoster virus (VZV) over a 24-month period from May 2018.

SETTING

Data were collected from 9 UK Paediatric Oncology Primary Treatment Centres.

PATIENTS

Children under 16 years old with a diagnosis of cancer and/or previous haematopoietic stem cell transplant who were VZV seronegative at exposure and/or diagnosis and received PEP following significant VZV exposure.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of breakthrough varicella within 6 weeks of VZV exposure and treatment with PEP.

RESULTS

A total of 105 eligible patients were registered with a median age of 4.9 years (range 1.1-10.5 years). Underlying diagnoses were acute leukaemia (64), solid tumours (22), Langerhans cell histiocytosis (9), central nervous system (CNS) tumours (8) and other (2). Aciclovir was received by 86 patients (81.9%), 18 received VZIG (17.1%) and 1 valaciclovir (0.9%). There were seven reported break-through VZV infections in 103 patients at follow-up (7/103, 6.8%). Clinical VZV developed in 5/84 of the aciclovir group (6.0%, 95% CI 2.0 to 13.3) and 2/18 of VZIG group (11.1%, 95% CI 1.4 to 34.7). All breakthrough infections were either mild (5/7) or moderate (2/7) in severity.

CONCLUSION

Aciclovir is a safe and effective alternative to VZIG as VZV PEP in children with cancer and should be considered as standard of care.

Post-exposure prophylaxis to prevent varicella in immunocompromised children

Background

Varicella-zoster virus (VZV) infection can cause life-threatening events in immunocompromised patients. Post-exposure prophylaxis (PEP) is required to prevent secondary VZV infection. Limited evidence is available for the use of acyclovir (ACV)/valacyclovir (VCV) as PEP.

Methods

Herein, we retrospectively analyzed immunocompromised paediatric patients with significant exposure to VZV. Patients administered PEP were categorized into four groups: 1) ACV/VCV group; 2) intravenous immunoglobulin (IVIG) group; 3) ACV/VCV/IVIG group; 4) vaccine group.

Results

Among 69 exposure events, 107 patients were administered PEP (91, ACV/VCV; 16, ACV/VCV/IVIG) and 10 patients did not receive PEP (non-PEP group). The index case was diagnosed based on clinical symptoms in 55 cases (79.7%). Fourteen cases (20.3%) were confirmed using direct virological diagnostic procedures. In the PEP group, only 2 patients (2.2%) developed secondary VZV infections. Additionally, 2 patients in the non-PEP group (20.0%) developed secondary VZV infection. The incidence of secondary VZV infection was significantly lower in the PEP group than in the non-PEP group (P=0.036). Among patients administered PEP, no antiviral drug-induced side effects were detected.

Conclusions

Antiviral agents administered as PEP are effective and safe for preventing VZV infections in immunocompromised patients. Rapid virological diagnosis of index cases might allow efficient administration of PEP after significant exposure to VZV infection.

Varicella post-exposure management for pediatric oncology patients

INTRODUCTION

The objective was to evaluate health care providers' (HCP) adherence to and efficacy of varicella post-exposure prophylaxis (PEP) recommendations. It was an observational, prospective, multicenter study set in Ile-de-France, France.

METHODS

All children under 18 with a cancer diagnosis, currently or within 3months of receiving cancer treatment, regardless of varicella zoster virus (VZV) serostatus or previous personal history of varicella, were eligible. Study participants with significant exposure were reviewed prospectively for PEP indications. Main outcome measures were the percentage of exposure situations for which HCP were guideline-compliant, the proportion of available VZV serostatuses and the incidence of breakthrough varicella after different PEP approaches.

RESULTS

A total of 51 patients from 15 centers were enrolled after 52 exposure episodes. Median age at exposure was 5 years (range, 1-15). Exposure within the household led to 38% of episodes. Prophylactic treatment consisted in specific anti-VZV immunoglobulins (V-ZIG) (n=19) or in oral aciclovir (n=15). No prophylactic treatment was given for 18 patients (in compliance, n=16). In compliance with guidelines, 17 patients received V-ZIG, 11 did not develop varicella (65%, [95% CI, 39-90%]); 15 received aciclovir, 13 did not develop varicella (87%, [95% CI, 67-100%]). Breakthrough varicella occurred in 11 patients, with simple clinical course in all cases; in 8/47 (17%) episodes when PEP was guideline-compliant versus 3/5 (60%) when not.

DISCUSSION

Recommendations have been respected and are efficient. PEP needs to be standardized and a study carried out to define the optimal approach. Anti-VZV immunization of seronegative family members should be encouraged.

Low complication rate in immunocompromised children with varicella-zoster virus infections in a single centre

AIM

Recent studies focusing on morbidity and mortality rates of immunocompromised children with varicella-zoster virus (VZV) infections are scarce. We aimed to summarise our experience.

METHODS

The study was a retrospective analysis of the medical records of children, who were admitted to Hadassah-Hebrew University Medical Centre, Jerusalem, Israel, during the period of 2008-2016. Data regarding baseline characteristics, treatment and outcome were extracted from patient's medical files.

RESULTS

We enrolled 74 patients (43% males) with a mean age of 8 (1-19) years. Most patients (72%) had no reported complications. Clinical outcome was favourable with 73 (99%) patients who had completely recovered and none died. Multivariable analysis identified the presence of fever (P = .005 and 0.02; hazard ratio (HR) 7.72 and 17.61, for total and herpes zoster groups, respectively) and prolonged interval period from clinical presentation to treatment onset (P = .021 and 0.025; HR 1.68 and 2.26, respectively), as associated with higher rates of complications.

CONCLUSION

Our results found low complication rate of VZV-associated infections in immunocompromised children admitted to a single centre. This should encourage conducting further large multicentre studies evaluating management of low-risk patients with oral acyclovir treatment.

Antiviraux chez l’enfant en pratique de ville : infections herpétiques, varicelle, grippe

Les infections liées à l’herpès virus humain (HSV), au virus de la varicelle et du zona (VZV) et au virus de la grippe (Influenza A et B) sont très fréquentes en pédiatrie et sont le plus souvent bénignes avec une guérison spontanée. L’utilisation des antiviraux antigrippaux (inhibiteurs de neuraminidase) a été étudiée dans de larges essais randomisés et fait l’objet de recommandations nationales et internationales. Celle des anti-HSV et anti-VZV n’a pas fait l’objet d’études de la même ampleur et de ce fait, leur prescription est plus discutée avec des bénéfices moins bien définis et variables (à l’exception des infections néonatales et/ou neuro-méningées). L’objectif de cette mise au point est donc de proposer une synthèse des données disponibles dans la littérature concernant les indications des antiviraux en pratique de ville pour les infections liées à l’HSV (gingivostomatite, herpès récurrent, faux panaris herpétique), au VZV (varicelle, zona) et à la grippe.

Nosocomial infection by human bocavirus and human rhinovirus among paediatric patients with respiratory risks

BACKGROUND

Nosocomial infections by respiratory viruses undetected by rapid tests are not often diagnosed. For paediatric patients with background diseases, nosocomial infection could be fatal.

AIM

To determine the relationship between developing symptoms by respiratory viruses undetectable by rapid tests and respiratory risks and to improve the management of infection control.

METHODS

Two episodes of nosocomial infection by human bocavirus (HBoV) and human rhinovirus (HRV) were retrospectively investigated in a tertiary hospital paediatric ward in Japan. Viruses were identified by polymerase chain reaction to determine infection control management. When viruses of the same species were detected from different patients, the virus homology was investigated. The relationship between respiratory risks and developing symptoms was statistically investigated.

FINDINGS

Three and four patients with respiratory risks in the HBoV and HRV outbreaks, respectively, developed respiratory symptoms. The nucleotide sequences of two patients in the HBoV outbreak and all four patients in the HRV outbreak were phylogenetically close. In both outbreaks, the patients with respiratory risks developed significantly more symptoms than those without any risk (P = 0.035 and 0.018, respectively). After the patients with respiratory infection were separated from those with respiratory risks, no additional nosocomial infection occurred.

CONCLUSION

Patients with respiratory risks easily develop respiratory symptoms and acquire severe symptoms of nosocomial infection by those viruses. In a paediatric ward, we should adopt not only standard precautions but also isolation management of the patients with respiratory symptoms, even if they have negative results in rapid tests.

PEPtalk2: results of a pilot randomised controlled trial to compare VZIG and aciclovir as postexposure prophylaxis (PEP) against chickenpox in children with cancer

OBJECTIVE

To determine the likely rate of patient randomisation and to facilitate sample size calculation for a full-scale phase III trial of varicella zoster immunoglobulin (VZIG) and aciclovir as postexposure prophylaxis against chickenpox in children with cancer.

DESIGN

Multicentre pilot randomised controlled trial of VZIG and oral aciclovir.

SETTING

England, UK.

PATIENTS

Children under 16 years of age with a diagnosis of cancer: currently or within 6 months of receiving cancer treatment and with negative varicella zoster virus (VZV) serostatus at diagnosis or within the last 3 months.

INTERVENTIONS

Study participants who have a significant VZV exposure were randomised to receive PEP in the form of VZIG or aciclovir after the exposure.

MAIN OUTCOME MEASURES

Number of patients registered and randomised within 12 months of the trial opening to recruitment and incidence of breakthrough varicella.

RESULTS

The study opened in six sites over a 13-month period. 482 patients were screened for eligibility, 32 patients were registered and 3 patients were randomised following VZV exposure. All three were randomised to receive aciclovir and there were no cases of breakthrough varicella.

CONCLUSIONS

Given the limited recruitment to the PEPtalk2 pilot, it is unlikely that the necessary sample size would be achievable using this strategy in a full-scale trial. The study identified factors that could be used to modify the design of a definitive trial but other options for defining the best means to protect such children against VZV should be explored.

TRIAL REGISTRATION NUMBER

ISRCTN48257441, EudraCT number: 2013-001332-22, sponsor: University of Birmingham.

Varicella Vaccination of Children With Leukemia Without Interruption of Maintenance Therapy: A Danish Experience

BACKGROUND

Varicella-zoster virus (VZV) can be fatal or cause severe complications in children with acute lymphoblastic leukemia (ALL). This analysis set out to investigate the morbidity and mortality of VZV vaccination without interruption of maintenance therapy in children with ALL.

METHODS

Files of 73 seronegative children with ALL were examined for data regarding VZV vaccination and infection, and long-term seroconversion was measured. Criteria before VZV vaccination were (1) seronegative, (2) in complete remission, (3) age ≥ 1.0 year, (4) lymphocyte count ≥ 0.6 × 10/L at time of vaccination and (5) receiving maintenance therapy.

RESULTS

Forty-five children were vaccinated. No child died or experienced serious adverse events due to VZV vaccination. Nine children developed late chickenpox despite vaccination. Long-term protection was found in 86% of children not receiving acyclovir and 78% of the entire population. Long-term seroconversion was found in 52% of the children. There were no severe cases of varicella infection. Acyclovir prophylaxis postvaccination was associated with an increased risk of late chickenpox [hazard ratio = 5.40 (1.43, 20.41), P = 0.01]. In contrast, a vaccine-induced rash reduced the risk of late chickenpox [hazard ratio = 0.08 (0.01, 0.66), P = 0.02]. No child had interruption of maintenance therapy at the time of vaccination, but 33% experienced discontinuation of therapy due to vaccine-induced rash. Dexamethasone was associated with an increased risk of vaccine-induced rash [hazard ratio = 2.9 (1.21, 6.90), P = 0.02].

CONCLUSIONS

This analysis indicates that VZV vaccination is feasible and justified in seronegative children with ALL, in countries where VZV vaccination is not part of the national vaccination program.

Incidence and consequences of varicella in children treated for cancer in Guatemala

BACKGROUND

Varicella-zoster virus infection is associated with significant morbidity and mortality in immune-compromised children, despite treatment with antiviral agents. Universal varicella vaccine programs have significantly decreased this risk in many highincome countries, but in most low-income and middleincome countries, the burden of varicella in children treated for malignancy is poorly defined.

METHODS

We retrospectively reviewed records of children at the National Unit of Pediatric Oncology (UNOP) in Guatemala diagnosed with varicella between January 2009 and March 2013 in order to calculate incidence of varicella and evaluate morbidity, mortality, treatment interruption, and cost.

RESULTS

Fifty-nine cases of varicella were identified. Incidence was 23.4 cases per 1000 person-years (p-y). 66.1% of cases occurred in children with leukemia (median age 5.2 years; interquantile range 3.4-7 years) and 41.0% of these occurred during maintenance therapy. Source of exposure was identified for 14/59 (23.7%) children. Most were hospitalized (71.2%) and given intravenous acyclovir (64.4%). Eight (13.6%) children required critical care, and two (3.4%) died from disseminated varicella with multiorgan failure. Chemotherapy was delayed or omitted due to varicella in 50%. No significant differences in outcomes based on nutritional and immunologic status were detected. The minimum average cost of treatment per episode was 598.75 USD.

CONCLUSIONS

Varicella is a significant problem in children treated for cancer in Guatemala, where effective post-exposure prophylaxis is limited. In the absence of universal varicella vaccination, strategies to improve recognition of exposure and the future use of novel inactivated vaccines currently under investigation in clinical trials could mitigate this burden.

Infectious complications in children with acute lymphoblastic leukemia treated in low-middle-income countries

Infections are the most important cause of morbidity and mortality in children treated for acute lymphoblastic leukemia (ALL). The rates of infection-associated mortality are up to 10-times higher in low- and middle-income countries (LMIC) than in high-income countries. The prevention, early recognition and management of infectious complications is especially challenging in LMIC because of disease and poverty-related factors, as well as the shortage of trained personnel, supplies, diagnostic tools and adequate organizational infrastructure. Children in LMIC with ALL, who are frequently underweight, are at increased risk of community-acquired pathogens, nosocomial multidrug-resistant pathogens and opportunistic microorganisms. This review summarizes the challenges of managing the major categories of infections in children receiving treatment for ALL and provides updated practical recommendations for preventing and managing these infections in LMIC.

Recent progress and concerns regarding the Japanese immunization program: addressing the "vaccine gap"

Recent progress in the Japanese immunization program has partially closed the "vaccine gap," i.e., the deficiencies in that program relative to immunization programs in other developed countries. During the last several years, seven new vaccines (12 new products, excluding influenza vaccines) have been introduced in Japan. Five of these new vaccines are produced outside Japan and four are now included as routine vaccines in the National Immunization Program, which is a new development in the licensing and financial support of imported vaccines. However, along with this progress, important concerns have arisen regarding the Japanese immunization program. A rubella epidemic among adults, in 2012-2013, resulted in more than 40 cases of congenital rubella syndrome as of March 2014. In addition, the temporary withdrawal of the active governmental recommendation for human papilloma virus vaccines, in 2013-2014, highlighted challenges in the current Japanese immunization system. Furthermore, some important vaccines - including vaccines for hepatitis B virus, mumps, varicella, and rotavirus - are still not included in the National Immunization Program and have been categorized as voluntary vaccines since their introduction. The possibility of their inclusion in the National Immunization Program remains a matter for discussion. We hope that future initiatives will further address the vaccine gap and protect Japanese children from vaccine-preventable diseases.

Postexposure prophylaxis for influenza in pediatric wards oseltamivir or zanamivir after rapid antigen detection

BACKGROUND

Postexposure prophylaxis (PEP) using neuraminidase inhibitors against exposure to influenza virus has been well studied in household settings but not in nosocomial settings in pediatric wards.

METHODS

We used oseltamivir or zanamivir as PEP in our pediatric wards. All influenza cases were diagnosed by the influenza rapid diagnostic test.

RESULTS

Between 2003 and 2011, there were 20 nosocomial introductions of influenza (10 were A, 9 were B and 1 was undetermined). The index cases consisted of 17 inpatients, 2 parents and 1 medical staff member. The 17 inpatients had been admitted to the hospital for reasons other than infectious disease and they developed influenza after hospitalization. Among the 81 contacts, 28 (35%) were exposed to influenza A, and 52 (64%) were exposed to influenza B. The rate of secondary infection among contacts not given PEP was 29% (5/17), and the rate among contacts given PEP was significantly lower, 3% (2/63; P = 0.004). The 2 infected contacts who had been given PEP were both influenza B cases, and both had received oseltamivir. The contacts who received PEP within 24 hours (59), for influenza A (23) and those who received zanamivir (15) did not develop influenza. No adverse events were reported.

CONCLUSIONS

PEP using oseltamivir or zanamivir for unexpected occurrences of nosocomial influenza in pediatric wards is safe and effective. The influenza rapid diagnostic test that we used was helpful for detecting nosocomial influenza in children.

Preventing varicella in children with malignancies: what is the evidence?

PURPOSE OF REVIEW

The prevention of varicella in children with cancer is generally agreed to be an important goal, because of their elevated risk of varicella zoster virus (VZV)-associated morbidity and mortality. However, there is a lack of consensus on the best means of achieving this. Here, we review the existing evidence in relation to postexposure prophylaxis against varicella in this group and summarize data regarding the role of active vaccination.

RECENT FINDINGS

Death from varicella during treatment for cancer is now rare, but VZV disease and its prevention remain significant problems in paediatric oncology practice. Measures to reduce VZV exposure amongst seronegative individuals are often neglected. When exposure is known to have occurred, early administration of varicella zoster immune globulin (VZIG) is generally protective against severe and complicated varicella. However, many centres in the UK and Japan use an oral antiviral agent, aciclovir, in place of VZIG. Published evidence for the efficacy of aciclovir as postexposure prophylaxis (PEP) relates mostly to healthy children, with no controlled studies in the immunocompromised.

SUMMARY

Good evidence already supports the administration of varicella vaccine to healthy susceptible family contacts of children with malignancy, but not to patients themselves. Further data are urgently needed to inform the choice of PEP against VZV in the immunocompromised.