Improving influenza vaccines: challenges to effective implementation.

Influenza virus causes contagious respiratory illness and remains a major burden on healthcare systems and the economy. Seasonal influenza vaccine is the most cost-effective way to combat the disease. However, underestimation of disease severity and controversy over vaccine safety and effectiveness hampers public confidence in vaccination. Action is needed to restore public confidence and improve vaccine uptake. Tailoring seasonal influenza vaccines according to immune responsiveness and infection/vaccination history of different populations can improve vaccine efficacy and effectiveness. Steady progress has been made in next generation influenza vaccine designs aiming at broad and long-lasting protective immunity in pre-clinical and clinical studies. However, substantial research and regulatory effort is required before reaching the goal of a truly universal vaccine.