s Severe Influenza: Clinical Features and Treatment Options

The first influenza pandemic in over 40 years was caused by a novel influenza A strain, A(H1N1)pdm09. Fortunately, most of those infected suffered mild disease. However, a significant minority of young adults and children exhibited severe illness, sometimes resulting in respiratory failure and even death. In the UK, A(H1N1)pdm09 influenza also caused a large disease burden the post-pandemic winter of 2010/11, stretching some healthcare resources to the limit. Although some pre-existing conditions increased the risk of severe disease, pregnant women and those with no underlying health problems contributed substantially to the total number of hospitalisations. Why outcomes of infection vary so widely is unknown and optimal personalised treatment strategies are yet to be developed. In this review, we give an overview of A(H1N1)pdm09 influenza in adults and the evidence supporting pharmacological interventions, with a focus on the use of antiviral agents.