Colds are a common upper respiratory tract infection usually caused by a virus. They come on gradually over a few days and usually improve within a week to 10 days. Symptoms are often milder than the flu. While more common during the winter months, you can still catch a cold any time of year.
Influenza, or the flu, is a highly contagious viral infection. Whilst it is another upper respiratory illness, it’s more severe than the common cold. Symptoms come on quickly and can be severe, lasting 1 to 2 weeks. The flu is generally seasonal, peaking during the cooler winter months. Active strains of influenza virus vary year to year, which is why a different flu vaccine is developed every year. The flu can develop into more serious conditions, including pneumonia.