Influenza: time to vaccinate but who and why?

The impact of influenza

William Farr, a doctor and statistician in the British Office of the Registrar-General, first described the phenomenon of influenza-associated excess mortality as early as 1847. This excess mortality significantly outweighs that attributed to influenza itself. The true mortality burden of the disease is not obvious, is difficult to tease out, and is still largely unappreciated by the general population and, sometimes, by healthcare workers.

Most influenza-associated mortality occurs in older adults and a significant proportion is recorded as being due to cardiovascular and cerebrovascular events. However, such deaths do not only occur in the older adult group, and at least one study found that influenza-related ischaemic heart disease deaths occurred mostly in the 40- to 64-year-old age group. Unfortunately, mortality is only a small part of the overall burden of influenza to the Australian healthcare system.