Coronaviruses are a group of viruses known for causing the common cold. They have a halo or crown-like (corona) appearance when viewed under an electron microscope. The common cold is an infection of the upper respiratory tract which can be caused by many different viruses.
Most often, common cold symptoms start 1 to 3 days after someone is exposed to a cold virus. Symptoms vary. They can include: Runny or stuffy nose. Sore or scratchy throat. Cough. Sneezing. Generally feeling unwell. Slight body aches or a mild headache. Low-grade fever.
Learn about the stages of a common cold, day by day, including the worst day of a common cold, why mucus gets thicker at the end, and what to expect by day five.
A cold begins when a virus attaches to the lining of your nose or throat. Your immune system -- the body's defense against germs -- sends out white blood cells to attack this invader.
Contrary to popular belief, cold weather or being chilled doesn't cause a cold. However, more colds do occur during the cold season (early fall to late winter).