Global influenza pandemics during the twentieth century resulted in millions of deaths. Imperial research which models the effects of intervention on the spread of pandemics is helping to ensure that we see a very different pattern in the twenty-first century.

Quick facts

  • 50 million: one estimate of the number of deaths during the 1918-1920 Spanish flu pandemic
  • 199: the number of countries reporting cases of the H1N1 pandemic in 2009

Prior to 2004 there existed very little quantitative research into the patterns and impact of pandemic flu. This meant that governments and global organisations seeking to plan for such events – through the stockpiling of vaccinations, for example, or the preparation of policies for travel restrictions and school closures – were hampered by a limited evidence base.

Building on their work in modelling seasonal influenza and new infections, including Severe Acute Respiratory Syndrome (SARS), Professor Neil Ferguson and colleagues began to address this gap by analysing data collected in historical flu pandemics, including the 1918 – 1920 pandemic which infected 500 million people. Alongside this research, the team developed an epidemic simulator capable of modelling the impact of multiple interventions during a pandemic at a global level. This modelling provided new insight into the feasibility of containing a pandemic at its source and the effect of antiviral measures and non-pharmaceutical public health policies.

Research into action

In 2009, the importance of this work was thrown into sharp relief. The outbreak of the H1N1 pandemic (widely known as swine flu) led to academics from Imperial’s MRC Centre for Outbreak Analysis and Modelling working in collaboration with the World Health Organisation (WHO) and multiple national governments to collect data on the virus’s transmission and severity in real time. Their analysis of that data, which suggested that the pandemic’s severity was only moderate in comparison with previous pandemics, informed policy-making. As the pandemic waned, the data collected at the height of the pandemic was published as an influential article in a leading journal.

Preparation and policies

The broader impact of Professor Ferguson’s work on pandemic flu continues to be felt today. The UK government, in developing its 2011 Pandemic Preparedness strategy, drew on his research to argue for an emphasis on annual stockpiling of antiviral medication, to be used in targeted vaccination programmes, and to recommend against travel restrictions, which has been shown to have a limited mitigating effect on flu transmission.

Both the European Union and the United States also took Imperial’s research into consideration when planning for pandemics, though interestingly, each recommend a different approach: while the European Centre for Disease Prevention and Control (ECDC) focused on the use of antivirals, the United States placed more emphasis on school closures and other non-medical interventions in its planning.

Overall, the research undertaken at the Centre has not only enhanced policy-makers understanding of pandemics themselves, it has given them the tools to manage public health crises and developed informed plans to minimise the health and economic impact of future pandemics.