The danger of delaying the second dose of hepatitis B vaccination for newborns. If the second dose is not delayed for too long, a difference of 2 or 3 days is not a problem, but if it is delayed for too long, the antibody titer produced by the first dose may be lower, or may not produce antibodies. In general, the antibody rate for the first dose of hepatitis B vaccine is relatively low, with only 30% of people producing antibodies. If it is postponed later, the infection may be caused by exposure during the postponement period, such as contact with a hepatitis B patient, transmission through blood or other transmission routes, ulcers on the skin or bleeding. Usually after the 2nd vaccination, 90% of people can produce antibodies, which can provide good protection for the baby. So postpone a few days, the impact is not too big, but do not postpone too long, in case it affects the 2nd vaccination to produce antibodies, it is recommended to do the vaccination in time.