Question
A parent brought their 2-year-old baby to the community health center for a 23-valent pneumococcal vaccine, only to discover later that the vaccine had expired. They are asking how to handle the situation.
Answer
Generally, vaccines are either attenuated or non-toxic and do not cause any adverse effects on the human body. The purpose of vaccines is to stimulate the immune system to produce antibodies. Even if an expired vaccine is administered, it may be ineffective, but it will not harm the body. It is recommended that parents not worry excessively and consult with a doctor to see if a re-administration is necessary.