The epidemiology of hepatitis a virus infection in children, in Edirne, Turkey Mehmet Sarper Erdogˇan 1 , Metin Otkun 2 , Muserref Tatman-Otkun 2 , Filiz Akata 3 & Mevlut Tu¨re 4 1 Kocaeli University Medical Faculty, Department of Public Health, Kocaeli; 2 Trakya University Medical Faculty, Department of Microbiology and Clinical Microbiology; 3 Trakya University Medical Faculty, Department of Clinical Bacteriology and Infectious Diseases; 4 Trakya University Medical Faculty, Department of Biostatistics, Edirne, Turkey Accepted in revised form 24 August 2003 Abstract. Turkey is a middle endemic area with re- spect to Hepatitis A virus (HAV) infection. However, the frequency of this infection varies due to socio- economic differences in various regions. The aim of this study was to detect the most likely age of expo- sure to HAV and factors affecting infection rates among children living in Edirne. A sample of 645 children between the ages of 0–19 living in Edirne were tested for total anti-HAV levels using ELISA method. A questionnaire on socio-economic status (SES), possible risk factors, and place of residence was completed for each child. Anti-HAV seroposi- tivity was found to be 4.4, 25, 37.3 and 43.2%, in 2–5, 6–10, 11–14 and 15–19 age groups, respectively. Seropositivity was found to be increasing with age (p < 0.05). According to logistic regression analysis results; mother’s education, SES of family, history of hepatitis in primary family members and the number of brothers or sisters were determined as factors in- creasing the seropositivity of HAV. Furthermore, HAV infection risk was found to be a decreasing function of income that is higher the income less likely the infection. These results showed that HAV infection rate in Edirne is in middle endemicity and the most likely way of exposure is transmission from family members. Although it requires further cost- effectiveness studies, our results indicate that apply- ing the HAV vaccination in early childhood would be beneficial to decrease the prevalence of the infection and prevent HAV epidemics. Key words: Childhood, Epidemiology, Hepatitis A virus, Risk factors Introduction Hepatitis A virus (HAV) infection is a fecal-orally transmitted disease, related to socio-economic status (SES) and personal hygiene. The prevalence and the age of HAV infection show regional differences and in respect to that: high, middle or low endemic areas have been defined. Turkey is known as one of the middle endemic countries with respect to HAV in- fection [1, 2]. However, the prevalence of this infec- tion varies according to socio-economical differences in various regions and by the time [3–5]. There is no known published data about epidemiology of HAV infection in Trakya region, which constitutes the European part of Turkey. Although HAV vaccine is available in pharmacies, it is not included in ‘Ex- panded Program on Immunization’ and it is not funded by the Turkish government. However, the discussions about who should routinely be vaccinated still continue [6]. In order to develop an effective HAV vaccination strategy, seroprevalence of HAV infection at different ages should be determined and cost-benefit analysis should be performed. This study was designed to detect the age of the child at the time of exposure to HAV, the factors affecting that age, and eventually to make suggestions on minimizing the rate of infection in our region. Another aim of the study is to determine the necessity of Hepatitis A vaccination of children living in Edirne. Methods Background Edirne is located at the border with Greece and Bulgaria in the northwestern part (Trakya region) of Turkey. The central settlement has a population of approximately 100,000. The 0–19 age group consti- tutes 36% of the total population. The design of the study The central settlement of Edirne is divided into eight districts. Table 1 gives the distribution of the popu- lation in the districts. In the planning of the study we wanted to be 95% confident that our estimate of the HAV prevalence rate in Edirne is within 4 units European Journal of Epidemiology 19: 267–273, 2004. Ó 2004 Kluwer Academic Publishers. Printed in the Netherlands.