The threat of human influenza: the viruses, disease impacts, and vaccine solutions.

Influenza is an acute respiratory illness that remains an important cause of excessive morbidity and mortality with substantial economic cost to the population. Influenza, being a virus that frequently mutates, is not amenable to elimination. Vaccination remains the most effective preventive measure. This review summarises the latest developments in the fields of biology and epidemiology relating to clinical and economic impacts of influenza disease, and vaccination. We suggest that future efforts should focus on developing safer, more effective, and cost-effective prophylactic vaccines for influenza.