Under normal circumstances, the polio vaccine is used in two ways: by injection and orally. In most cases, the inactivated polio vaccine is first injected when the child reaches 2 months of age and the site of injection is usually chosen to be on the front inner side of the thigh; when the child reaches 3 months, 4 months and 4 weeks of age, the polio vaccine is changed to live attenuated vaccine to be taken orally at these three times. The polio vaccine is a free vaccine, and the oral vaccine is a light pink drop. Parents need to give the vaccine to their children on time, which can effectively help prevent polio.