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

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.

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.

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.