Vaccine-preventable diseases are a significant cause of morbidity and mortality. As new vaccines are proving to be effective and as the incidence of some infections decreases, vaccination practices are changing. Healthcare workers (HCWs) are particularly exposed to and play a role in nosocomial transmission, which makes them an important target group for vaccination. Most vaccine-preventable diseases still carry a significant risk of resurgence and have caused outbreaks in recent years. While many professional societies favor vaccination of HCWs as well as the general population, recommendations differ from country to country. In turn, vaccination coverage varies widely for each microorganism and for each country, making hospitals and clinics vulnerable to outbreaks. Vaccine mandates and non-mandatory strategies are the subject of ongoing research and controversies. Optimal approaches to increase coverage and turn the healthcare workforce into an efficient barrier against infectious diseases are still being debated.

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.

Morbidity and mortality of influenza are increased in immunocompromised patients. For instance, mortality rate of influenza infection can reach 9% in patients treated in oncology [1]. Hence, vaccination against influenza is recommended in immunocompromised patients, including those receiving anticancer chemotherapy, irrespective of their age. However, vaccine coverage remains poor in high-risk patients: 25% of adults aged 18–64 years, increasing with the patient's age (18% in the 18- to 49-year group and 32% in the 50- to 64-year group) [2].

Background: Methods: Results: Conclusion: