Declining seroprevalence of hepatitis A in Vojvodina, Serbia

Abstract

To assess the current hepatitis A virus (HAV) endemicity in the Autonomous Province of Vojvodina, Serbia, we examined the seroprevalence and susceptibility profiles of the general population. A serum bank of 3466 residual samples, collected in 2015–16 as per the specifications of the European Sero-Epidemiology Network 2 project (ESEN2), was tested for anti-HAV antibodies with an enzyme immunoassay. Relationships between anti-HAV positivity and demographic features of respondents were examined by univariable and multivariable analyses. Present-day HAV seroprevalence was compared with that obtained in 1978–79. Surveillance data for hepatitis A recorded between 2008 and 2017 were also analyzed. Age was the only demographic variable found to be independently associated with a HAV seropositive status. Seropositivity (17% overall vs . 79% in 1978–79) increased with age to a maximum of 90% in the elderly ≥60 years. Only 5% of subjects <30 years were seropositive, unlike the 44% of seropositives ≥30 years. The estimated age at midpoint of population immunity (AMPI) increased markedly from 14 years in the late 70s to 55 years in 2015–16. Meanwhile, disease incidence decreased noticeably in recent years (from 11 in 2008 to 2 per 100,000 population in 2017). In the ongoing pre-vaccine era, natural infection provides immunity for merely a third (31%) and two thirds (57%) of people in their 40s and 50s, respectively. Hence, the majority of people ≤40 years (94%) and middle-aged adults 40–49 years (69%) are susceptible to HAV. Older susceptible individuals, particularly those ≥50 years (24%), are prone to severe symptoms. Taken together, these changes reflect the epidemiological transition of Vojvodina and Serbia from high to very low HAV endemicity, thereby supporting the current national policy of immunization of only high-risk groups.

Epidemiological Transition and Strategies for the Control of Hepatitis A in Serbia

“…A serosurvey conducted on samples collected in 2015–2016 showed that HAV seroprevalence in Vojvodina increased with age from 3.1% in the age group 5–9 years to 89.6% in people ≥ 60 years old [ 14 ]. By the age of 30 years, only 5% of individuals are seropositive, leaving the majority of children and young adults susceptible to HAV.…”

“…The Republic of Serbia is an upper–middle-income country located in central–south–eastern Europe. A previously published seroprevalence study provided evidence that HAV circulation has declined over the past four decades; thus, Serbia ranks as a very low-endemicity country nowadays, supporting the national policy of vaccination of high-risk groups [ 14 ]. National legislation opted for recommended vaccination against HA for vulnerable population groups (PID, liver transplant patients, people who work in poor hygienic conditions, and MSM) as well as for nonimmune individuals without any special risk.…”

Comparison between immune-chromatography (ICT) and ELISA techniques for detection of anti-HAV antibodies among patients suspected to be infected with Hepatitis A virus (HAV)

“…It is transmitted by a fecal-oral method which happens either by direct contact with feces or indirectly by ingestion of food or water contaminated by fecal matter of the infected persons 5 . The clinical course of HAV infection is age-dependent and ranges from asymptomatic (commonly in children aged ≤ 5 years) to acute symptomatic hepatitis, with higher severity of disease in the older population 6 . The common symptoms of hepatitis infection include fever, nausea, vomiting, anorexia, general fatigue, and abdominal pain where the liver is located.…”