Exploring hepatitis A dynamics in Israel, 2019–2022

Abstract

BackgroundContinuous monitoring of Hepatitis A Virus (HAV) may assist in identifying local outbreaks. The advent of the COVID-19 pandemic, which affected the circulation of numerous pathogens, may have also impacted the scope of HAV infections. AimTo investigate the incidence and environmental dissemination of HAV between 2019 and 2022 in Israel, a country with an anti-HAV vaccination program. MethodsHAV RT-PCR analysis was performed for all HAV cases and for 280 sewage samples collected in 2019–2022. Available amplified HAV fragments from clinical (n = 107) and sewage (n = 27) were also assessed by genotyping and phylogenetic analysis. ResultsIn 2019–2022, 158 individuals and 12.9 % (36/280) of sewage samples were HAV-RNA positive. Median age was 30 years (IQR 20.5–44); approximately half (51.9 %, 82/158) were males. Almost all patients (98.4 %, 124/126) were not vaccinated. Highest numbers were identified in 2019 (84 cases and 30 %, 21/71, positive sewage samples). In 2020, when three COVID-19 related lockdowns were implemented, 24 cases and 4.3 % (3/69) sewage samples were HAV-RNA positive. The number of HAV-RNA positive cases and positive sewage samples remained low in 2021–2022 (31 and 19 cases, 13.2 %, 9/68 and 4.2 %, 3/72 positive sewage samples, respectively). Sub-genotype IB dominated (90.7 %, 97/107 of cases and 81.5 %, 22/27 of sewage samples), and phylogenetic analysis of HAV samples demonstrated small transmission clusters of sequences from Jews, Bedouin Arabs and foreign workers. Sub-genotype IA was identified in 8.4 % (9/107) of cases and in 18.5 % (5/27) of sewage samples. ConclusionCombined clinical and environmental surveillance is optimal for monitoring HAV. In 2020, the circulation of HAV decreased, possibly following COVD-19 health restrictions. In subsequent years, the incidence remained low. Adults in risk-groups for HAV infection should be vaccinated to minimize HAV circulation.