Pneumonia—most commonly, secondary bacterial pneumonia—is the most frequent complication of influenza. Influenza infection may also worsen cardiovascular disease. While this relationship is not completely understood, an autoimmune reaction that produces vascular injury may be the underlying cause for this complication in patients with CVD. [36] People with diabetes may have abnormalities in their immune function, which may lead to an increased risk of morbidity and mortality from infection. [38] Influenza vaccination has reduced the number of hospitalizations and deaths in patients with high-risk chronic conditions. [1]
