It takes about two days to get a cold after exposure to the virus. In this video, Larry Gooss, DO, a family practice doctor at Chippenham & Johnston-Willis Hospitals, explains how virus can continue to live on surfaces.
A RealAge answered. To prevent vitamin C deficiency, government guidelines recommend a daily dose of 90 milligrams (mg) for men, 75 mg for women. We recommend that you get 1,200 mg of vitamin C per day from food and supplements. This higher amount not only prevents deficiency but also helps prevent disease and needless aging.
Most of the studies Moyad and his colleagues examined used 500 daily milligrams of vitamin C to achieve health results. That's much higher than the RDA of 75-90 milligrams a day for adults. So unless you can eat plenty of fruits and vegetables, you may need to take a dietary supplement of vitamin C to gain all the benefits, Moyad says. He suggests taking 500 milligrams a day, in addition to eating five servings of fruits and vegetables.