Influenza

Influenza is an acute upper respiratory illness caused by a virus member of the Orthomyxoviridae family affected by minor annual mutations and more infrequently major genome mutations with dramatic pandemic potential. An infection with very high transmission rate that occurs in seasonal winter epidemics worldwide and affects a significant proportion of the whole population and develops severe pulmonary complications in the elderly and in high-risk groups; this resulting in high levels of work/school absenteeism and productivity losses; clinics and hospitals can be overwhelmed during peak periods of illness. Estimated cost of those seasonal epidemics can significantly affect the national budget. Global influenza surveillance has been conducted through WHO’s Global Influenza Surveillance and Response System (GISRS). Prevention of influenza is based on moderately effective influenza vaccines reformulated annually according to virus type circulation and non-medical interventions. Therapy is recommended in high-risk individuals with dedicated antivirals.