Immunogenicity and safety of the influenza A H1N1v 2009 vaccine in cancer patients treated with cytotoxic chemotherapy and/or targeted therapy: the VACANCE study

Influenza vaccination is recommended to cancer patients undergoing chemotherapy, but vaccine coverage remains low. During the 2009 influenza pandemic, French recommendations were to vaccinate immunocompromised patients with two doses of adjuvanted vaccine. This study aimed to evaluate vaccine immunogenicity in cancer patients receiving chemotherapy. VACANCE is a prospective open-label study that evaluated the immunogenicity and safety of two doses of AS03A-adjuvanted H1N1v vaccine in cancer patients receiving cytotoxic and/or targeted therapies. Serum haemagglutination-inhibited antibody titres against influenza A H1N1v were measured at days 1, 21, and 42, to estimate the proportion of participants with antibody titres ≥1:40 [seroprotection rate (SPR)], the efficacy of seroconversion, and factors that increased the geometric mean titre. Sixty-five patients were included. At baseline, 5% of patients had vaccine strain titres of specific haemagglutination inhibition antibodies that were ≥1:40. After one and two doses of vaccine, SPRs were48% and 73%, respectively, and seroconversion rates were 44% and 73%, respectively. Vaccine-related adverse events were mild to moderate. A single dose of AS03-adjuvanted A/H1N1 vaccine triggered a low immune response in cancer patients on chemotherapy depending on their treatment type and frequency. Two doses are needed for these cancer patients.