Impact of Obesity on Immunity to the Influenza Virus: Gut Microbiota, Mechanisms, and Novel Therapeutic Strategies

Obesity affects millions of individuals globally, and a deeper understanding of its associated physiological disturbances is essential for addressing key public health concerns. It has been demonstrated that the influenza virus possesses substantial global epidemic potential, with higher incidence rates observed in obese individuals and prolonged recovery times. Obese individuals exhibit impaired immune organ function, decreased immune cell activity, disrupted metabolism characterized by mitochondrial dysfunction, and an imbalance in gut microbiota associated with intestinal mucosal barrier damage. The gut microbiota and their metabolic composition in obese patients differ from those in non-obese individuals, potentially promoting viral replication and exacerbating disease severity. These factors collectively contribute to more severe tissue damage and heightened immune responses in obese patients during influenza infection. Therefore, understanding the impact of obesity on influenza virus infection dynamics enables the development of strategies promoting healthy lifestyles to manage body weight and enhance immunity against viral infections. Additionally, given that this special population may not respond optimally to antimicrobial drugs and vaccination, it is necessary to consider how treatment strategies for this group are managed. This review illustrates findings concerning the impact of obesity on the immune response to influenza virus infection, including potential underlying mechanisms.