Hepatitis B virus, HCV and HIV continue to be significant causes of morbidity and mortality all over the world and are endemic in South East Asia including Afghanistan (
1). The limited epidemiological data on these diseases have been obtained either from specific groups or from Afghan immigrants living in neighboring countries such as Iran and Pakistan. Vaccination program including HBV has begun within the last five years in Afghanistan. According to WHO the rate of vaccination with three doses of HBV vaccine in children younger than one-year was 85% in 2008 and 83% in 2009 (
1). Despite the socioeconomic condition of Afghanistan, transition to vaccination program for an endemic disease and the vaccination rates seem promising. The results of our study reflected the effects of the vaccination program. In this study, HBsAg seropositive results were 0.6% for the children between one and six years of age, whereas the rate was 6.5% in children between six to 15 years of age. Similarly, anti-HBs seropositive results were significantly higher in children between one and six years of age (19.3%) than in children between six to 15 years of age (9.5%). This significant difference between children between one and six years of age and children older than six years might be a result of the vaccination program. There was not any information available about the vaccination schedule of our patients because of the low literacy rate of the parents. Even if the vaccination was done, no document related to the name or dose of the vaccines was available.
The prevalence of HBsAg in limited and specific groups of Afghans has been reported between 1.23% and 8.3% (
6-
11). In studies from Pakistan, the prevalence of hepatitis B infections is between 1.7% and 5.5% in the children (
13). There is no data available concerning the prevalence of HIV or HCV in Pakistan or Afghanistan. Studies on the prevalence of HBsAg in Afghanistan did not reflect the entire population as they included specific populations such as sex workers, intrapartum women, and intravenous drug users, with an incidence rate between 1.5% and 6.5% (
7-
9,
14). High values are reported especially from the Afghan refugee camps in neighboring countries. The prevalence rate of HBsAg in Afghan immigrants in Balochistan of Pakistan was 8.3% (
10). The same study reported the incidence of HBsAg between the ages of three to 23 years as 5.6% out of 301 patients (
10). Since 2001, three million immigrants returned back to Afghanistan, mainly to Kabul. Since more people are planning to return, this might be considered as a significant risk for the country. The Central Blood Bank in Kabul reported the HBsAg frequency in donors as 3.9% from March to December 2006 (
6). In our study, the frequency of HBsAg was 3.6% between the ages of one to-15 years. The only study including the same age group was from Balochistan camp by Quddus et al. with a prevalence rate of 5.6% (
10). Our lower prevalence might be related to the age group, higher rate of horizontal transmission in the camp area, and fully vaccination with three doses of HBV vaccine in only 1% of children in the area. The studies among special populations with higher risk factors had, as predicted, higher rate of seropositive results. Todd et al. (
7) reported HBsAg prevalence 1.53% in 4452 intrapartum women and they related this low rate to the higher incidence of HBsAg carriage in men and to sexual transmission. The present study results were similar to the results of Central Blood Bank of Kabul. The increase in drug users, unhealthy injection practices, the return of immigrants back to Afghanistan, and the ongoing war over a decade are the major concerns about the increase in the HBsAg prevalence. The studies on Afghan population reported anti-HCV prevalence rate between 0.3% and 36.4% (6,8,9). The rate is high (36%) especially in intravenous drug users (
9). The increase in the use of intravenous drugs in Afghanistan is a matter of concern. Many studies reported anti-HCV prevalence as follows: 1.9% by Central Blood Bank of Kabul, 0.3% in obstetric population by Todd et al. report, and 1.92% in sex workers (
6,
8,
14,
15). In this study, only 2 (0.6%) children with anti-HCV positive results, were found, in the age group of six to 15 years. Fathers of both children had also anti-HCV positive results. Risk factors for transmission of HCV in childhood are limited and risk of transmission may increase with age. Studies concerning HIV seroprevalence were also similar with an incidence of 0-3%; however, data pertaining to the children population were not clear (
6-
9,
15). The incidence increases to 3%, especially in intravenous drug users. Similar to HCV, the increase use of intravenous drugs correlates with the higher seropositive results. No anti-HIV positive results were detected in the present study. In our study which can be explained by the small sample size and maybe less intravenous drug users in comparison to the neighboring countries due to lower socioeconomic conditions. One limitation to our study was that it might not reflect the prevalence in all regions of Afghanistan and the sample size was small; however, this was the preliminary study from Afghanistan. As a result, HBV, HCV and HIV are endemic in Kabul province in adults but in children there is not enough data; hence, epidemiological studies with larger populations from different areas of Afghanistan, which might reflect the true status of country regarding these infections prevalence, seem essential.