Characteristics of patients admitted to Intensive care units with severe Influenza and management outcome at a large district general hospital in East of England, UK

Influenza pneumonia can be challenging to treat particularly in critically ill patients. The aim of this study is to review the risk factors for severe influenza infection, the course of the disease, the choice of antivirals and the management outcome in patients admitted with complicated influenza illness to ICU

Sixteen patients who were admitted to ICU at West Hertfordshire hospitals NHS Trust with severe influenza illness were reviewed between 20th December 2018 and 14th February 2019. Data on Demographics, vaccination status, viral strain and clinical outcome were collected and analysed.

High proportion of patients were below the age of 65 (n=9).The predominant strain was A(H1N1) pdm09 (n=10), followed by A(H3N2) (n=5) and 1 patient had no strain reported. All patients were initiated on Oseltamivir. Six patients developed multi-organ failure and were switched to IV Zanamivir. None of the latter were severely immunosuppressed. 56.25% (n=9) were not vaccinated and third with unknown status (n=5). 66% of the patients below the age of 65 were not vaccinated and had to switch to Zanamavir. Fourteen patients made good recovery and 2 died while on Zanamavir

Our result suggest that the majority of patients admitted to ICU did not carry risk factor for complications and were below the age of 65, but were unvaccinated and infected with A(H1N1)pdm09 strain. Larger study is required to fully understand the risk factors for ICU admission including vaccination status in this group of patients and the optimum antiviral choice.