Update on Influenza Vaccines: Needs and Progress.

Influenza is an annual seasonal epidemic, and occasionally pandemic, respiratory disease that causes considerable morbidity and mortality worldwide. Despite the widespread availability of safe and effective vaccines since the 1950s, this virus continues to pose a significant public health threat. Variable and often weak vaccine effectiveness, antigenic drift and shift, and vaccine hesitancy are some of the obstacles that must be overcome to control this disease. In this article, we briefly review current influenza vaccines, address safety concerns and the need for newer influenza vaccines of higher efficacy, and discuss efforts to create broadly protective, universal influenza vaccines.