The Epidemiological Patterns of Hepatitis C in Lithuania: Changes in Surveillance from 2005 to 2018.

Background and Objectives: Viral hepatitis C infection is an important public health concern worldwide because it is one of the major global causes of death and morbidity. The early identifi-cation of infected people, together with the provision of proper treatment, are the key strategies used in preventing HCV infection. However, data regarding the epidemiological patterns of hep-atitis C in Lithuania are limited. The aim of this research was to evaluate trends in acute HCV cases registered via the national surveillance system in Lithuania during 2005-2018. Materials and Methods: Incidence rates were calculated for data, stratified by gender, age group (0-24, 25-54, 55-74, and 75+), place of residence (urban or rural), and the Lithuanian county where the case was recorded. The crude incidence rate of hepatitis C was defined as the number of new infec-tions per 100,000 people during a one-year time period. A linear regression was applied to evalu-ate IR trends during the period of 2005-2018. Results: From 2005 to 2018, 572 cases of acute hepa-titis C were registered, and the incidence rate ranged from 2.03 cases per 100,000 people in 2005 to 0.55 in 2016. A statistically significant decreasing trend in the incidence rate was found during the study period (p < 0.0001). Almost 63% of the acute HCV infections recorded via the national surveillance system were in individuals aged from 25 to 54 years. Conclusions: Being male, aged between 25 and 34 years, and living in the city might be important factors for understanding the epidemiological patterns of HCV in Lithuania. Although the number of HCV cases recorded in Lithuania is decreasing, our country has one of the highest IRs compared to other European countries. This shows that a new approach to hepatitis C virus screening strategies is needed.

Prevalence, incidence and residual risk of transfusion transmitted viruses (HBV, HCV and HIV infections) in Lithuanian blood donors from 2004 to 2018: The incidence/window-period model study.

INTRODUCTION: Estimation of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) transfusion risk in blood donors is essential for monitoring the safety of the blood supply and the impact of new screening tests. Due to improvements in donor selection and continuing progress in screening assays, residual risk of virus transmission has significantly decreased over the past years. It is not practical and sometimes even not possible to measure residual risk in blood donors directly and mathematical models are used. The aim of this study was to calculate the prevalence, incidence rates of HBV, HCV and HIV infections and analyse evolution of their transmission residual risk from 2004 to 2018 at the National Blood Center of Lithuania. MATERIALS AND METHODS: Data from the archives of the National Blood Center of Lithuania from 2004 to 2018 was retrospectively analysed. The residual risk was calculated for each virus and year by applying the incidence/window-period model suggested by World Health Organization. For the analysis of the residual risk yearly trends a linear regression was used. RESULTS: A total of 754,755 blood donors and 1,245,568 donations were included in the analysis and represented a 2.06 donations per donor over 15 years. Average residual risk for HBV, HCV and HIV respectively was 570.04, 807.14 and 35.72 per 1,00,000 donations. During the study period, there was statistically significant downward trend in the residual risk for every analysed virus. DISCUSSION: Residual risk of virus transmission has been steadily decreasing over past 15 years in Lithuanian donors, but the current risk remains quite high. It is difficult to establish how much the risk is affected by statistical assumptions or virus prevalence in general population. However, results of this study indicate the need of the population screening program of transfusion transmitted viruses.