Question
Can a six-month-old child be tested for Hepatitis B surface antigens?
Answer
There are generally no restrictions on when to perform a Hepatitis B surface antigen test. If you want to check whether the Hepatitis B vaccine has been successfully administered, it is recommended to test 20 days after the completion of the full Hepatitis B vaccine series. Individual differences vary, and the chance of producing antibodies is not the same for everyone. Generally, after the first dose, only 18% of people produce antibodies within two weeks; after one month, this increases to 41%; after the second dose, 80-90% of vaccine recipients produce antibodies; and after the third dose at six months, 96% of individuals develop a positive antibody response, which can last for several years.