Incidence and case-fatality of varicella-zoster virus infection among pediatric cancer patients in developing countries

Abstract

Limited evidence is available about varicella-zoster virus (VZV) infection among pediatric cancer patients in developing countries, which raises questions about the generalizability of VZV vaccine recommendations for pediatric cancer patients (derived from developed countries) to these settings. We assessed the incidence and case-fatality of VZV infection at three institutions in developing countries (Argentina, Mexico, and Nicaragua). Individuals eligible for our study were aged <20 years and actively receiving cancer-directed therapy. We estimated a summary incidence rate (IR) and case-fatality risk with corresponding 95 % confidence limits (CL) of VZV infection across sites using random-effects models. Our study population comprised 511 pediatric cancer patients, of whom 64 % were aged <10 years, 58 % were male, and 58 % were diagnosed with leukemia. We observed a total of 10 infections during 44,401 person-days of follow-up across the 3 sites (IR = 2.3, 95 % CL 1.2, 4.2). The summary case-fatality risk was 10 % (95 % CL 1.4, 47 %) based on one death.

Conclusion: Our results suggest low incidence and case-fatality of VZV infections among pediatric cancer patients in three developing countries. VZV vaccine recommendations for pediatric cancer patients in developed countries may be generalizable to developing countries.

What is known: • Current recommendations, based on evidence from pediatric cancer patients in developed countries, contraindicate varicella-zoster virus (VZV) vaccination until completion of cancer-directed therapy and recovery of immune function. • The generalizability of these VZV vaccine recommendations to pediatric cancer patients in developing countries is unknown because of limited information about the incidence and case-fatality of VZV in these settings. What is New: • Our results suggest low incidence and case-fatality of VZV infections among pediatric cancer patients in three developing countries. • VZV vaccine recommendations based on evidence from pediatric cancer patients in developed countries may be generalizable to pediatric cancer patients in developing countries.

Keywords: Cancer; Infection; Pediatric; Vaccine; Varicella-zoster virus.