Exploring hepatitis A dynamics in Israel, 2019-2022

Area of Science:

• Virology
• Public Health
• Epidemiology

Background:

• Continuous monitoring of Hepatitis A Virus (HAV) is crucial for identifying local outbreaks.
• The COVID-19 pandemic may have influenced the circulation patterns of various pathogens, including HAV.

Purpose of the Study:

• To investigate the incidence and environmental dissemination of HAV in Israel from 2019 to 2022.
• To assess the impact of the COVID-19 pandemic on HAV circulation within a country with an established vaccination program.

Main Methods:

• HAV RT-PCR analysis was conducted on clinical cases and sewage samples collected between 2019 and 2022.
• Genotyping and phylogenetic analysis were performed on amplified HAV fragments from both clinical and environmental samples.

Main Results:

• 158 individuals and 12.9% of sewage samples tested positive for HAV RNA between 2019-2022.
• HAV incidence peaked in 2019 and significantly decreased in 2020 during COVID-19 lockdowns, remaining low through 2022.
• Sub-genotype IB was dominant, with phylogenetic analysis revealing small transmission clusters among diverse populations. Most infected individuals were unvaccinated.

Conclusions:

• Combined clinical and environmental surveillance effectively monitors HAV.
• COVID-19 restrictions likely contributed to the observed decrease in HAV circulation.
• Targeted vaccination of adults in risk groups is recommended to reduce HAV transmission.