Maths adds new weapon in fight against pandemics

Mathematicians have developed a powerful tool to quantify the spread and infectiousness of viruses like the pandemic H1N1 flu strain, which can be used together with modern laboratory techniques to help the healthcare system plan its response to disease outbreaks. By putting statistical data under the microscope, University of Warwick researchers have created a model to predict the impact of future pandemics in real-time as they strike. During the 2009 outbreak, the true extent of H1N1 was difficult to detect as in some people it caused severe symptoms, even death, whereas in others it was so mild that they did not realise they had the virus. During an outbreak like this, it is vital that public health authorities have a clear picture of the disease among the population so they can take precautionary measures such as distributing antibiotics or closing schools if necessary. When H1N1 struck three years ago, the main source of information in the UK was laboratory testing of nose and throat swabs taken from people who went to the doctor with symptoms of the virus. But tracking the virus through this method alone has been shown to underestimate the true number of cases as those who had mild symptoms would not have gone to their doctors and would have been missed in the data. This underestimate has been confirmed by subsequent studies of blood samples from the wider population taken at the time of the outbreak, which showed that around 90 per cent of cases were missed.