Hepatitis A is mainly transmitted through the gastrointestinal tract. Close contact with people with hepatitis A, sharing utensils, teacups, and toothpaste, and eating food and water contaminated with the hepatitis A virus can lead to infection. Hepatitis A often causes epidemic outbreaks in collective units. Once infected, hepatitis A must be treated in isolation for as little as 21 days, and full recovery takes six months. Therefore, it is important to create a good sanitary environment and to “prevent hepatitis A before it happens”. Since Chinese people have long developed party-style eating habits, it is not easy to keep the “disease from the mouth”. The hepatitis A vaccine, however, can produce high levels of antibodies and provide good immunity. The hepatitis A vaccine is a non-blood product and is not contagious to hepatitis A or other diseases. It is worth reminding that vaccination must be given at a regular institution to be safe and effective. But the vaccine, a substance between a drug and a pathogen, has been compared to a fierce crocodile, but the teeth have been artificially removed. Therefore, vaccines do not bring toxic reactions to the body, but can help the body to complete the “immune building”, which is somewhat like giving the body immunity to do “military exercises”, until the day there are really germs attacking the body, the body already has the corresponding “weapon defense”. The body already has the appropriate “weapons to defend”. However, since we are conducting immune exercises in the body, we have to suffer from occasional “gunfire” and side effects after vaccination. What should I do if I get a rash after vaccination? Due to the differences in immunity of the human body, a few people may experience mild redness and swelling or slight pain at the vaccination site after vaccination, which usually subsides within 24-72 hours and is a normal adverse reaction to the hepatitis A vaccine. Very few people may experience allergic rash, malaise, fever, anorexia, diarrhea, nausea, vomiting, etc. This kind of adverse reaction to hepatitis A vaccine is also usually transient, and most of them can be relieved on their own within 24 hours. Therefore, there is no need to worry too much about the rash on the body after vaccination, and you can first keep an eye on it for observation. If the rash does not resolve in more than 24 hours, it is recommended to visit a hospital for regular treatment and therapy under the guidance of a doctor.