Cancer Patients Undergoing Chemotherapy Show Adequate Serological Response to Vaccinations Against Influenza Virus and Streptococcus pneumoniae

Cancer patients receiving chemotherapy are prone to develop infections that might postpone treatment and lead to complications. The aim of our study was to investigate whether a heterogeneous population of patients with solid tumors and malignant lymphoma undergoing chemotherapy would respond serologically to vaccination against influenza and pneumococcal disease. There are no established routines in oncology departments in Norway regarding vaccination of these patients. The study included 35 cancer patients with median age 53 yr (range 20-74) and 38 controls with median age 57 yr (range 43-75). The chemotherapy regimens used were mild or moderately immunosuppressive. After one vaccination, 25 patients (72%) and 34 controls (87%) were serologically protected against two or three influenza strains. A higher proportion of patients with solid tumors (81%) than lymphoma (38%) achieved protection. Age, months on chemotherapy, and curative versus palliative treatment did not influence responses to vaccination. After vaccination with a 23-valent polysaccharide vaccine against pneumococci, most patients and controls achieved protective serum levels of antibodies against the different serotypes, with the exception that fewer patients were protected against serotype 4. The responses in controls were, however, generally stronger to all serotypes. Tumor type did not influence this vaccination response. We conclude that our cancer patients achieved adequate responses to influenza virus and Streptococcus pneumoniae. These are not live vaccines and are therefore safe for immunocompromised patients. Routine vaccinations against influenza virus and Streptococcus pneumoniae should be considered in cancer patients undergoing mild to moderately immunosuppressive chemotherapy.