04.Why haven't they cured the common cold yet?
There are more than 200 different viruses that cause the common cold. More than half are rhinoviruses, thought to be responsible for about 30-35% of colds. Coronaviruses are also responsible for a large percentage of colds, but are less understood because they’re difficult to grow in labs . You can’t identify the virus responsible for a particular cold by its symptoms because they’re so similar, and different people react to one virus in different ways.
Unlike the flu, the common cold is not highly contagious, and even if you’re infected you may not have much in the way of symptoms – you may have multiple viruses sitting in your nose creating no more than the odd sneeze . Your immune response, which can be affected by stress and fatigue, determines the severity of cold symptoms.
White blood cells, which battle the virus, cause most of your misery. They release kinins - chemicals that cause swelling and inflammation of the blood vessels in the nose, throat and lungs, resulting in symptoms such as stuffiness, congestion and a sore throat. Excess proteins and fluids leach from blood and lymph vessels, creating mucus. Fever, fatigue, aches and pains are the body’s way of telling you to rest up and save your energy for fighting the virus. Antibodies are not produced until towards the end of the cold cycle, so they can’t do much more than hang around until you get the same virus again.
Not only is there a large number of viruses to contend with, but the viruses also tend to mutate quite frequently, making it hard to keep on top of them.
Another problem for scientists is that animals (with the exception of the chimpanzee) don’t react to the viruses the same way we do . This makes laboratory testing of potential treatments difficult and costly. However, scientists have now developed a genetically-modified mouse that can be infected by rhinoviruses, potentially leading to treatments that could prevent some of the more serious complications of colds.