Influenza in Vulnerable Populations

Abstract

Influenza is a ubiquitous virus that results in thousands of deaths annually, particularly in those vulnerable to it. Vulnerability is manifested in two different scenarios: when the whole population becomes susceptible, such as when resistant or rare strains start to predominate; and in the individual prone to infection, such as those at the extremes of age, from colonised populations, or with chronic disease. The first three chapters address situations that have population impact. Chapter 1 reviews literature on oseltamivir-resistance. Circulating strains are largely receptive to oseltamivir, but recently resistant strains have predominated, highlighting the need for alternative strategies. Chapter 2, a randomized controlled trial, shows no clinical or virological advantage to doubling the standard dose of oseltamivir. Chapter 3 reviews the application of polyclonal antibodies to neglected diseases like avian influenza with promising results as to safety and immunogenicity. The latter chapters focus on those who are demographically at risk. Chapter 4 asks which antiviral strategies work best to prevent and manage influenza outbreaks in aged care facilities. A protocol is proposed for treatment alone versus treatment plus prophylaxis. Obtaining participation consent is an unresolved issue. In Chapter 5, oseltamivir pharmacokinetics in infants is presented with sparse published data. Results support current dose recommendations. Chapter 6 examines among Indigenous Australians the intersection of a higher rate of both chronic disease and of severe influenza during the 2009 pandemic. The first age-standardised national analysis of government-collected data is included. With no clear correlation, results suggest effects of colonisation other than disease are responsible for higher influenza rates.