Influenza vaccination in HIV-positive subjects: latest evidence and future perspective

Annual influenza vaccination is recommended for persons with human immunodeficiency virus (HIV) infection. Recent reports indicate that immunizations may increase HIV replication in infected individuals. Generally, vaccination against influenza is well tolerated in both children and adult individuals with HIV and does not induce significant changes in viral load and CD4+ cell counts. The observed increase in viral replication is usually transient and a clear, measurable progression of the underlying HIV disease is hard to be determined. Several studies reported immunogenicity data in HIV+ population, by comparing different influenza vaccines, adjuvanted or not, and different administration routes. Data are encouraging because an adequate immune response is shown, although split/subunit vaccines do not elicite an efficient immune response in these subjects. New strategies have been evaluated to increase the immune response in immunocompromised patients.The aim of this review is to evaluate tolerability, safety, immunogenicity and efficacy of vaccines actually approved for human use and to consider latest evidence and future perspective in HIV positive subjects.