From vitamin C and echinacea to warm clothes and antibacterial soap, there’s no shortage of ideas about how to prevent and manage colds and flu. Unfortunately, many of these are not based on solid scientific evidence. In fact, medical researchers are only starting to unravel the range of factors that affect our susceptibility to getting an infection. Now we have discovered that our body clock plays an important role – making us more prone to get infected at certain times of the day.