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

ABSTRACT

Varicella in oncology patients can result in serious complications. We analyzed trends in hospitalization rates and characteristics of pediatric oncology and non-oncology patients hospitalized with varicella during the first 7 years after introduction of routine varicella vaccination. Our data included children <17 years of age with an International Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) main or secondary discharge diagnosis of varicella identified by annual database queries in 22–29 pediatric hospitals in Bavaria (Germany) in 2005–2011. Of a total of 1,245 varicella-associated hospitalizations, 42 children (median age 4 years, interquartile range 3–5) had an underlying malignancy (67% with acute lymphoblastic leukemia). Overall, additional diagnoses potentially associated with varicella were reported less often in oncology than in non-oncology varicella patients (62% vs. 77%, p = 0.041), suggesting earlier hospitalization of high-risk patients. Acute hematological diagnoses (29% vs. 3%, p < 0.001) and coinfections (invasive 12% vs. 2%, p = 0.001; noninvasive 19% vs. 8%, p = 0.019) were more frequent, whereas neurological (5% vs. 19%, p = 0.023) and upper respiratory tract diagnoses (2% vs. 16%, p = 0.014) were less frequent in oncology compared to non-oncology varicella patients. Oncology varicella patients showed a longer hospital stay (median 5 vs. 3 days, p < 0.001). Hospitalization rates in non-oncology varicella patients declined constantly since 2006, from 114.8 (2006) to 30.5 (2011) per 1,000 pediatric beds. The rates of varicella-associated hospitalizations in oncology patients indicated an overall decreasing trend (3.8, 1.9, 4.6, 3.5, 0.4, 2.1 and 0.6 cases per 1,000 pediatric beds in 2005–2011). Thus, pediatric oncology patients potentially profit from herd protection effects, resulting from increasing vaccine coverage in the general population.

KEYWORDS:

• Children
• hospitalization
• oncology
• surveillance
• varicella zoster virus

Acknowledgments

The authors thank Karin Seeger for the valuable comments on the manuscript, and Sabrina Hanke and Christina Bungartz for their support in data management. They also thank the following hospitals for participation in the study: Kreisklinik Altötting, Zentrum für Kinder-und Jugendmedizin (Altötting); Klinikum St. Marien Amberg, Klinik für Kinder und Jugendliche (Amberg); Klinikum Aschaffenburg, Klinik für Kinder-und Jugendmedizin (Aschaffenburg); Klinikum Augsburg, Klinik für Kinder und Jugendliche (Augsburg); Klinik Josefinum, Kinderkrankenhaus (Augsburg); Klinikum Sozialstiftung Bamberg, Kinderklinik (Bamberg); Klinikum Bayreuth GmbH, Kinderklinik (Bayreuth); Regiomed-Kliniken gGmbH, Klinik für Kinder-und Jugendmedizin (Coburg); DONAUISAR Klinikum Deggendorf, Kinder-und Jugendmedizin (Deggendorf); Universitätsklinikum Erlangen, Kinder-und Jugendklinik (Erlangen); Klinikum Fürth, Klinik für Kinder und Jugendliche (Fürth); Klinikum Garmisch-Partenkirchen GmbH, Fachabteilung Kinder-und Jugendmedizin (Garmisch-Partenkirchen); Sana Klinikum Hof GmbH, Kinderklinik (Hof); Klinikum Kaufbeuren, Abteilung Pädiatrie (Kaufbeuren); Klinikum Kempten-Oberallgäu, Kinderklinik (Kempten); Klinikum Landsberg am Lech, Abteilung für Kinder-und Jugendmedizin (Landsberg); Kinderkrankenhaus St. Marien, Abteilung für Kinder-und Jugendmedizin (Landshut); Städtisches Klinikum München GmbH, Klinikum Harlaching, Klinik für Kinder-und Jugendmedizin (München); Ludwig-Maximilians-Universität München, Dr von Haunersches Kinderspital (München); Städtisches Klinikum München GmbH, Klinikum Schwabing, Klinik für Kinder-und Jugendmedizin (München); Klinikum Dritter Orden, Klinik für Kinder-und Jugendmedizin (München); Kliniken St. Elisabeth, Abteilung für Kinder-und Jugendmedizin (Neuburg a.d. Donau); Klinik Hallerwiese, Cnopf'sche Kinderklinik (Nürnberg); Klinikum Nürnberg, Klinik für Neugeborene, Kinder und Jugendliche (Nürnberg); Kinderklinik Dritter Orden (Passau); Krankenhaus Barmherzige Brüder Regensburg, Klinik für Kinder und Jugendmedizin (Regensburg); RoMed Klinikum Rosenheim GmbH, Kinderklinik (Rosenheim); Leopoldina-Krankenhaus der Stadt Schweinfurt GmbH, Klinik für Kinder und Jugendliche (Schweinfurt); Klinikum Starnberg, Klinik für Kinder-und Jugendmedizin (Starnberg); Kliniken Südostbayern AG, Klinikum Traunstein, Klinik für Kinder-und Jugendmedizin (Traunstein); Kliniken Nordoberpfalz AG, Klinikum Weiden, Klinik für Kinderheilkunde und Jugendmedizin (Weiden); Universitätsklinikum Würzburg, Kinderklinik und Poliklinik (Würzburg); and Missionsärztliche Klinik gGmbH, Kinderklinik (Würzburg).

Declaration of interest

The Bavarian Varicella Surveillance Project was financially supported by an unrestricted research grant from GlaxoSmithKline (GSK) Vaccines (Rixensart, Belgium) from 2006 to 2011. AS and JGL received further research grants from both manufacturers of varicella vaccine, GSK and Sanofi Pasteur MSD. AS and JGL received support for conference attendance, and AS honoraria for expert meetings from GSK and Sanofi Pasteur MSD. VW declares no conflict of interest.