ost upper respiratory tract infections (URTI) are caused by viruses. Familiar to us all, they include the common cold and similar illnesses with symptoms such as cough, sore throat and runny or blocked nose. More serious infections such as influenza (AK A flu) and SARS‑CoV‑2 (AKA Covid-19) can affect both the upper and lower respiratory tract, inflict more serious symptoms and take longer to recover from. Most of us suffer a common cold or similar URTI two to four times per
