By Adam Kleczkowski, Professor of Mathematics and Statistics, University of Strathclyde Glasgow, Nov 10 (The Conversation) As the days get shorter and the weather colder in the northern hemisphere, health officials have warned of a perfect storm of infectious respiratory diseases over the winter months. Outbreaks of seasonal diseases like influenza and respiratory syncytial virus (RSV) are already putting pressure on the overburdened NHS. If surges of these illnesses collide with another large COVID wave, we could be facing a public health disaster. Some have called this threat a “tripledemic”. But how can we realistically expect the winter to play out? To try to answer this question, we can look at the recent and current trends of some of the most common winter infections in the UK.