Background
: Although adult immunization is as important as childhood immunization, is being inadequately performed. However, previous studies concerning adult immunization could not be sufficiently evaluated because studies were restricted to the residents in rural area or those who have visited a doctor.

Methods : We conducted a study by telephone interview which included 201 households(375 adult family members)selected by systematic sampling from the yellow pages of Kangnam-gu and Sungbuk-gu districts of Seoul. The types of immunization covered in this study were immunizations against hepatitis B, influenza, pneumococcus, and hemorrhagic fever with renal syndrome(HFRS). Immunization status of all adult household members, cognition of the need for immunization and of interviewees were surveyed. Sex, age, area of residency, education, medical history of study subjects were considered as factors related to the cognition of the need for immunization and immunization performance.

Results : The cognition rates of immunization were as follows : hepatitis B 85.1%, influenza 45.8%, pneumonia 38.3%, and HFRS 33.8%. In the people over 65 years old, the cognition rate against influenza and pneumococcus were 6.25%, 6.25% respectively and for those who have chronic disease. 80.0%, 20.0%, respectively. The cognition rates of immunization was significantly higher among those subjects who were young, well educated, and those residing in Kangnam-gu district.
The immunization performance rate of hepatitis B was 62.5%, influenza 5.6%, pneumonia 0.8%, and HFRS 1.1%. 75.8% of subjects vaccinated against hepatitis B had received at least three times. The immunization performance rate of influenza and pneumococcus by the immunization indication are as follows : 8.0%, 0.0%, respectively in the subjects over 65 years old, and 11.1%, 0.0% respectively in the people who have chronic diseases. The immunization performance rate of hepatitis B was higher among young, well educated subjects living in Kangnam-gu district. But age, education, area of residency played no apparent role in the case of other types of immunization.
The immunization performance rate of those who felt the need for immunization as significantly higher than that of those who did not. To assess the factors which relate to the correct cognition for immunization necessity, we used a multiple logistic regression test. For all types of immunization surveyed, sex(females) and age(young) seemed to be significantly related to the correct necessity cognition. Medical history of chronic disease was also related to the correct necessity cognition for immunization against hepatitis B and influenza.

Conclusion : This study reveals that among living in urban area the immunization performance rate and the correct cognition rate concerning the necessity for adult immunization was generally very low. Therefore, an active publicity and public education will be needed to increase the level of correct necessity cognition for immunization in which the disease status, sex, and age of vaccinee are considered. And more active effort to increase the cognition for immunization necessity performance is required.