Varicella in pediatric oncology patients in the post-vaccine era-Analysis of routine hospital data from Bavaria (Germany), 2005-2011

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.

Viral reactivations following hematopoietic stem cell transplantation in pediatric patients - A single center 11-year analysis

Viral reactivation occurs frequently in the context of immunodeficiency and immunosuppression after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and can cause severe complications. The aim of this single-center retrospective analysis was to characterize viral infections in the first year after HSCT, to investigate risk factors and to study the impact of viral infections on transplantation outcome. This will facilitate the identification of at-risk patients and the development of new preventive strategies. 107 pediatric allo-HSCT from January 2005 through December 2015 were analyzed for infections with Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), adenovirus (ADV), herpes simplex virus (HSV) and varicella zoster virus (VZV). Viral infections were detected after 68.2% of transplantations. The viruses most commonly encountered were HHV-6 (36/107) and EBV (30/107). Severe viral disease was rare (7/107) and none of the patients died as result of viral reactivation. Important risk factors for viral infections were higher age at HSCT, donor type and occurrence of acute graft-versus-host disease (aGvHD). Especially for EBV, transplant from an unrelated donor and in-vivo T-cell depletion (TCD) had a significant effect on infection rates, whereas for CMV the strongest effect was seen by donor and recipient serostatus with recipient seropositivity most predictive for reactivation. The occurrence of severe aGvHD was associated with EBV and ADV infections. For HSV, the recipient serostatus was identified as prognostic factor for HSV infections, while we found higher age at time of HSCT as risk factor for VZV infections. The overall survival of patients with or without viral infections did not differ significantly. Interestingly, when looking at the 85 patients in our cohort who had received an HSCT for a malignant disease, a tendency towards lower relapse rates was seen in patients affected by viral infections (HR 0.51, 95% CI 0.25 - 1.06, p = 0.072). Viral reactivations are common after pediatric allo-HSCT, though severe complications were rare in our collective. Determining risk factors for viral reactivations may help to identify patients in need of intensified monitoring and to individualize preventive strategies.

Specific Varicella-Related Complications and Their Decrease in Hospitalized Children after the Introduction of General Varicella Vaccination: Results from a Multicenter Pediatric Hospital Surveillance Study in Bavaria (Germany)

BACKGROUND

Universal varicella vaccination (UVV) for children introduced in Germany in 2004 resulted in a significant overall decline of varicella-related hospitalizations (VRHs). We investigated the incidence of specific types of varicella-related complications (VRCs) in hospitalized children and the impact of UVV on VRCs during the first 7 years of UVV.

METHODS

Children < 17 years of age hospitalized with an ICD-10-based (International Classification of Diseases, 10th Revision) discharge diagnosis of varicella were identified as VRH in pediatric hospitals in Bavaria by annual standardized data queries of the hospital databases (2005-2011). For each VRH, the hospitals reported basic demographic data, duration of hospital stay, all diagnostic and procedural codes, and outcome. VRCs were reported overall, per year, and by immune status. Complication rates were calculated as mean number per complication category per hospital and per year; VRC trends over time were assessed by linear regression.

RESULTS

Between 78% (2005) and 61% (2011) of Bavarian hospitals participated and reported a total of 1263 VRHs. Specific VRCs were reported in 954 (76%) children. Complication rates per hospital and year decreased from 6.7 [95% confidence interval (CI): 5.1-8.3] in 2005 to 1.5 (95% CI: 0.8-2.3) in 2011, with the strongest reduction of 90% in children < 5 years of age from 5.3 (95% CI: 4.0-6.6) in 2005 to 0.5 (95% CI: 0.1-0.9) in 2011. Significant decreases were observed for children with upper respiratory tract (URT, by 97%), lower respiratory tract (LRT, by 90%), skin (by 81%), gastrointestinal (by 78%), and neurologic (by 65%) VRCs. Forty-eight children with VRCs were immunocompromised; their annual rate decreased by 87%.

DISCUSSION

Corresponding to increasing varicella vaccination coverage in the population, the incidence of VRC decreased by 77% from 2005 to 2011, with the most substantial decrease in the target group for UVV.

CONCLUSION

Within 7 years, UVV in Germany led to a decrease of about 77% of all types of VRCs, with the highest reductions observed for VRCs of the respiratory tract.