Safety of live attenuated influenza vaccine in mild to moderately immunocompromised children with cancer

BackgroundThe safety of intranasal live-attenuated influenza vaccine (LAIV) in immunocompromised children with cancer is unknown. The objective of this study was to describe the safety and immunogenicity of LAIV in mild to moderately immunocompromised children with cancer.MethodsWe conducted a multicenter, randomized, double-blind study of LAIV versus placebo in children aged 5–17 years with cancer. LAIV (frozen formulation) or allantoic fluid/buffer was administered intranasally. Reactogenicity, adverse events, blood for immune assays, and nasal swabs for viral shedding were obtained during 5 visits over the first 42 days postvaccination; information concerning serious adverse events (SAEs) was collected for 180 days.Results20 subjects were enrolled (LAIV, n = 10; placebo, n = 10) with a mean age of 12.2 years. Ten subjects had hematologic malignancy (LAIV, n = 4; placebo, n = 6); 10 subjects had solid tumors (LAIV, n = 6; placebo, n = 4). One subject was excluded from immunogenicity analysis for not receiving a full dose of LAIV. LAIV resulted in an increased incidence of runny nose/nasal congestion occurring in all LAIV recipients; no related SAEs were observed. Four of 10 LAIV recipients shed vaccine virus, with none exceeding 7–10 days duration. LAIV demonstrated modest immunogenicity by hemagglutination inhibition (≥4 fold rise for any strain, 33%) and microneutralization assays (≥4 fold rise for any strain, 44%).ConclusionIn this small pilot study conducted in mild to moderately immunocompromised children with cancer, runny nose/nasal congestion was increased in LAIV recipients, no related SAEs occurred, and prolonged viral shedding was not detected. Moderate immunogenicity was demonstrated in this small group of individuals. (ClinTrials.gov: NCT00112112).

► LAIV has not been studied in mild/moderately immunocompromised children with cancer.
► We conducted a double-blind placebo controlled Phase 1 study in this population.
► The safety and tolerability profile was comparable to that in healthy children.
► Immunogenicity was modest in this heavily prevaccinated population.
► Viral shedding was not prolonged compared with healthy children.