Year-To-Year Variation of Deaths in English Small Areas, and the Interaction between a Presumed Infectious Agent and Influenza in 2015

Deaths in England and Wales in 2015 showed the largest increase over the previous year seen in nearly 50 years. This was partly due to a seasonal influenza outbreak in late 2014 with deaths peaking in January 2015, however, deaths had already shown a step-like increase earlier in 2014 due to an outbreak of a presumed infectious agent. Outbreaks of the other agent between 2002 and 2014 were characterised in very small areas, and this was compared to behaviour in 2015. Both agents were shown to have the potential to spread across all parts of England and Wales. Latest research in immunology is employed to demonstrate that the unusually high deaths in 2015 could have arisen from sequential infection within an overarching framework of the infectious burden in humans. The interaction between the other agent and influenza illustrates how a chance series of events, which may include influenza vaccination, can generate unexpected large increases in mortality and morbidity.