Abstract and Introduction
Yearly administration of the influenza vaccine is the main strategy to prevent influenza in immunocompromised patients. Here, we reviewed the recent literature regarding the clinical significance of the influenza virus infection, as well as the immunogenicity and safety of the influenza vaccine in HIV-infected individuals, solid-organ and stem-cell transplant recipients and patients receiving biological agents. Epidemiological data produced during the 2009 influenza pandemic have confirmed that immunocompromised patients remain at high risk of influenza-associated complications, namely viral and bacterial pneumonia, hospitalization and even death. The immunogenicity of the influenza vaccine is overall reduced in immunocompromised patients, although a significant clinical protection from influenza is expected to be obtained with vaccination. Influenza vaccination is safe in immunocompromised patients. The efficacy of novel strategies to improve the immunogenicity to the vaccine, such as the use of adjuvanted vaccines, boosting doses and intradermal vaccination, needs to be validated in appropriately powered clinical trials.
The influenza virus infection remains associated with significant morbidity and mortality, particularly in high-risk populations, such as immunocompromised patients, the elderly and patients with cardiopulmonary conditions.[1,2] In immunocompromised patients, influenza is associated with a high rate of bacterial pneumonia, other opportunistic respiratory infections, hospitalization and even death.[3,4] Thus, prevention of influenza is of major importance in this population. Yearly vaccination is the main strategy to prevent influenza and it is widely recommended for immunocompromised patients.[5,6] However, immunogenicity of the vaccine can be impaired by the immunosuppressive condition, and there have been some concerns regarding the safety of the vaccine in specific populations, particularly in solid-organ transplant (SOT) recipients.
The primary purpose of this article is to assess the clinical relevance of influenza in immunocompromised patients, including HIV-infected individuals, SOT and hematopoietic stem-cell transplant (HSCT) recipients, and patients receiving biological agents. We then focus on reviewing the existing literature on the immunogenicity, efficacy and safety of the influenza vaccine in these populations. Finally, novel strategies to increase the immune response to the vaccine are discussed.
Immunotherapy. 2014;6(2):131-139. © 2014 Future Medicine Ltd.