Diarrhea is generally known clinically as diarrhea. If diarrhea occurs the day before the vaccination, and the symptoms improve the next day and are not accompanied by other symptoms of infection such as fever, vaccination is generally allowed. If diarrhea is still present on the day of vaccination, or if symptoms such as fever, abdominal pain, nausea, or vomiting occur, this indicates a condition of infection, and vaccination is not appropriate at that time. Vaccination is used to combat disease-causing pathogenic microorganisms by stimulating the body to produce specific antibodies through the inoculation of antigenic components of pathogenic microorganisms. Because the vaccine contains allogeneic protein components and immune adjuvants, the body can produce both beneficial and adverse immune responses to the allogeneic protein. If the body itself has an abnormal condition with reduced tolerance and stress response capacity, the unfavorable immune response may intensify, while the disease itself may further worsen. Therefore, patients are not suitable for vaccination during either acute illness or the active phase of chronic illness. Patients who are not sure whether they are suitable for vaccination can consult the staff at the vaccination site and follow the medical advice for a safer and more effective injection.