Vaccination Against Respiratory Infections in Adults with Cancer: A Concise Guide for Clinicians

Global cancer incidence reached 20 million new cases across 185 countries in 2022, with approximately 10 million cancer-related deaths annually. Among adults with solid tumors and hematological malignancies, infections are a major contributor to morbidity and mortality, with respiratory infections playing a particularly significant role. These infections not only reduce life expectancy but can also delay cancer therapy, negatively affect treatment outcomes, and increase healthcare costs. In recent years, the burden of respiratory infections in this population has been driven by influenza virus, SARS-CoV-2, respiratory syncytial virus, <i>Streptococcus pneumoniae</i>, and <i>Bordetella pertussis</i>. Effective vaccines are available for all these pathogens and are recommended for adults with cancer, yet vaccination uptake remains suboptimal despite their heightened vulnerability. This review provides practical guidance for healthcare professionals on vaccinating adults with cancer against respiratory infections, summarizing key information to help clinicians address vaccination-related complacency, confidence, and convenience. Evidence from studies in both the general population and cancer patients consistently shows that vaccination benefits outweigh potential risks, with adverse event rates comparable to those seen in individuals without cancer. Early vaccination is encouraged, as there is limited justification for delaying immunization even when immune responses may be reduced. Vaccine dosing aligns with recommendations for the general population, with important exceptions. Live attenuated vaccines should be avoided because of the risk of replication and disease in immunocompromised patients, and selected groups may require booster doses to achieve adequate protection. Notably, cancer immunotherapy does not appear to impair vaccine-induced immune responses.