After your baby has received the second dose of hepatitis B vaccine, watch for fever, rash or allergies. Drowsiness is a relatively rare condition, probably not significantly related to the vaccine, and usually gets better in 1-2 days. Hepatitis B is a chronic infectious disease that seriously threatens the health of our people, and China is a large country with hepatitis B. Some people are infected with hepatitis B due to mother-to-child transmission at birth. In order to interrupt mother-to-child transmission, all newborns in our country are vaccinated against hepatitis B free of charge. The hepatitis B vaccination produces effective hepatitis B surface antibodies to protect against hepatitis B virus infection. The hepatitis B vaccination requires three doses over a six-month period to produce a high concentration of hepatitis B surface antibodies. People with protein allergies are not able to receive the hepatitis B vaccine, but for most people the vaccination is still very safe.