It is generally recommended not to get wet within a week after the hepatitis A vaccination and not to take a bath, because premature bathing may cause skin ulceration and redness at the injection site and inflammation may occur. In addition, after the hepatitis A vaccination, patients should take more rest and drink more water to maintain their immunity. Some patients may experience mild fever and drowsiness after vaccination, but if the symptoms are mild, it is fine to drink water and rest actively. However, if patients have allergic reactions, nausea, vomiting or even dizziness, they need to go to a regular medical institution for further infusion treatment. In addition, some hypersensitive patients may have delayed allergic reactions after vaccination, such as skin rashes, panic attacks, shortness of breath, and anaphylaxis, which are extremely rare. However, if these cases occur, it is necessary to actively consider going to the emergency department of a regular medical institution for anti-allergic treatment.