感冒是由病毒引起的一种上呼吸道感染性疾病，一年四季均可发生，而以气候变化剧烈的冬春季为多。由于人患感冒后，免疫力弱，加之引发感冒的病毒种类多，型别更多，这些病毒能交叉感染，但无交叉免疫，防治有一定难度，因而一个人短期内可多次染上感冒。据统计，全球平均每年 Colds are a type of upper respiratory infection caused by a virus that can occur throughout the year, mostly in winter and spring, where climate change is severe. Because people suffer from cold, weak immunity, combined with the types of viruses that cause a cold, more types, these viruses can cross-infection, but no cross-vaccination, prevention and treatment have a certain degree of difficulty, so a person can be infected with cold in the short term . According to statistics, the world average each year