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Immunogenicity of a two‐dose regime of varicella vaccine in children with cancers
Author(s) -
Leung TingFan,
Li ChiKong,
Hung Emily C. W.,
Chan Paul K. S.,
Mo ChiWai,
Wong Raymond P. O.,
Chik KiWai
Publication year - 2004
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.2004.00216.x
Subject(s) - medicine , varicella vaccine , vaccination , varicella zoster virus , immunology , immunogenicity , chickenpox , seroconversion , chickenpox vaccine , virology , immune system , virus , immunization
Objective: Live‐attenuated varicella vaccine is effective and safe in immunocompetent children. In this study, we assess the immunogenicity and adverse events following varicella vaccination in immunosuppressed cancer children. Methods: Varicella‐zoster virus (VZV)‐seronegative cancer children received two doses of live‐attenuated VZV vaccine (Varilrix ® ) in a span of 3 months. Patients with acute lymphoblastic leukaemia (ALL) were in the maintenance phase of chemotherapy, whereas those with solid tumours joined the study around 3–6 months from treatment discontinuation. VZV‐specific cellular and humoral immune responses were measured before and after VZV vaccination. Results: The median (range) age of the 17 patients was 4.4 yr (2.0–14.5). Thirteen had ALL, one had myelodysplastic syndrome and three had solid tumours. Following vaccination, the VZV‐specific stimulation index (SI) increased from 1.7 (0.9–2.9) to 17.9 (5.9–36.0) ( P < 0.001). Similarly, SI to phytohaemagglutinin mitogen increased from 1136 (499–1930) to 1714 (848–2518) ( P = 0.028). There were also significant increases in CD4+ cells and CD4 : CD8 ratio as well as a reduction in CD16/56+ cells in peripheral blood lymphocytes. Seroconversion rate to VZV was 19% after one dose and increased to 94% after the second dose of VZV vaccine. Serum VZV‐specific IgG concentrations also increased significantly following two doses when compared with one dose of VZV vaccine ( P = 0.0004). One subject developed possibly vaccine‐related chickenpox with self‐limiting hepatitis at 5 wk following vaccination. None of the patients developed herpes‐zoster at a median (range) follow‐up of 27.5 months (24.0–30.0). Conclusions: Non‐immune cancer children can be effectively vaccinated against chickenpox at the defined period. However, the safety of chickenpox vaccine in these immunosuppressed children needs to be further studied.