If an infant takes a bath after vaccination, in order to prevent infection at the vaccination site, you can sterilize the site with iodine povidone after it dries; if there is infection at the injection site, fever, etc., then symptomatic treatment is needed. 1. Infection at the injection site: babies generally need to take a bath after 24 hours after vaccination, because the injection site needle eye has not yet healed, if you take a bath within 24 hours, you can use povidone-iodine to disinfect the vaccination site after drying. If there is an infection at the injection site, use iodophor to wipe and disinfect it, and local hardness, redness and swelling can be relieved by applying local hot and cold compresses. 2. Fever: Some infants may have fever after vaccination, mostly due to immune response. If the fever is low, then take physical cooling (use warm water to wipe the forehead, armpits, groin and other capillary-rich parts), if the temperature is greater than 38.5 degrees Celsius or more, under the guidance of a physician to apply ibuprofen granules and other antipyretic drugs. Infants should avoid bathing within 24 hours after vaccination, and if any adverse reaction occurs, they need to go to the hospital for treatment, and they should not use any medication by themselves.