Influenza infection

Uncomplicated seasonal influenza infection

Seasonal influenza is usually a self-limiting acute respiratory illness that recurs each winter season as different strains emerge. Annual influenza vaccines are available to immunise against the strains expected to circulate. If seasonal influenza is contracted, institution of antivirals within 36 to 48 hours of onset of symptoms will decrease days of illness by 1 to 2 days and reduce lower respiratory tract complications.​[110]Centers for Disease Control and Prevention. Influenza antiviral medications: summary for clinicians. Dec 2023 [internet publication]. https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm ​[116]Doll MK, Winters N, Boikos C, et al. Safety and effectiveness of neuraminidase inhibitors for influenza treatment, prophylaxis, and outbreak control: a systematic review of systematic reviews and/or meta-analyses. J Antimicrob Chemother. 2017 Nov 1;72(11):2990-3007. http://www.ncbi.nlm.nih.gov/pubmed/28961794?tool=bestpractice.com ​​

Complicated seasonal influenza: viral pneumonia

Patients considered at high risk for seasonal influenza may develop a lower respiratory tract complication of viral pneumonia. This may require more aggressive supportive care or hospitalisation.

Complicated seasonal influenza: bacterial pneumonia

Patients who have an initial improvement of their respiratory illness followed by recurrence of fever and cough with productive sputum may have a bacterial pneumonia complicating the seasonal influenza infection. This may require more aggressive supportive care, appropriate antibiotic therapy, and/or hospitalisation.