The use of supplementation with other types of vitamins has also been described in viral infections; the use of vitamin C, for example, a potent antioxidant and an important enzyme cofactor, contributes to the development of the immune response, helping in the production of type I IFN. However, a systematic review with meta-analysis found no evidence that the use of vitamin C has any effect in preventing common cold infections (213). As for vitamin E, it has been shown that its deficiency can impair cellular and humoral immune responses (214). However, the use of vitamin E has been associated with an increased risk of pneumonia and has shown no significant effect in preventing lower respiratory tract infections (215, 216).