The Haemophilus influenzae type b (Hib) vaccine was introduced into the routine immunization schedule in Turkey on January 1, 2007. This study investigates the immunity to Hib prior to the introduction of the vaccine. Materials and methods: Serum samples were collected from healthy volunteers between the ages of 6 months and 50 + years of age, living in the area of 26 health centers in the Samsun, Antalya, and Diyarbakir provinces during 2000-2001. In total, 1713 sera were selected for this study, and the younger age groups were given priority (range 0-82). A commercial ELISA test was used to measure anti-Hib IgG. Hib antibody concentrations of 0.15 to < 1.0, and >= 1.0 µg/mL were considered as non protective, short-term protection, and long term protection, respectively. The statistical analyses performed were the chi-square test and logistic regression. Results: The antibody levels considered non-protective were 58.0%, 35.3%, 28.1%, 19.8%, 18.4%, 15.3%, and 20.6% among < 5, 5-9, 10-19, 20-29, 30-39, 40-49, and 50 and over age groups, respectively. Protection against Hib infection increased by age in all 3 provinces. Conclusion: This study provides important baseline data on anti-Hib antibody levels in Turkey before routine immunization was introduced, and shows that there is a considerable percentage of subjects with non-protective antibody levels.

The Haemophilus influenzae type b (Hib) vaccine was introduced into the routine immunization schedule in Turkey on January 1, 2007. This study investigates the immunity to Hib prior to the introduction of the vaccine. Materials and methods: Serum samples were collected from healthy volunteers between the ages of 6 months and 50 + years of age, living in the area of 26 health centers in the Samsun, Antalya, and Diyarbakir provinces during 2000-2001. In total, 1713 sera were selected for this study, and the younger age groups were given priority (range 0-82). A commercial ELISA test was used to measure anti-Hib IgG. Hib antibody concentrations of 0.15 to < 1.0, and >= 1.0 µg/mL were considered as non protective, short-term protection, and long term protection, respectively. The statistical analyses performed were the chi-square test and logistic regression. Results: The antibody levels considered non-protective were 58.0%, 35.3%, 28.1%, 19.8%, 18.4%, 15.3%, and 20.6% among < 5, 5-9, 10-19, 20-29, 30-39, 40-49, and 50 and over age groups, respectively. Protection against Hib infection increased by age in all 3 provinces. Conclusion: This study provides important baseline data on anti-Hib antibody levels in Turkey before routine immunization was introduced, and shows that there is a considerable percentage of subjects with non-protective antibody levels.