The routine detection, surveillance, and reporting of novel SARS-CoV-2 variants is crucial, as these threaten to hinder global vaccination efforts. Herein we report a novel local variant with a non-synonymous mutation in the spike (S) protein P681H. This local Israeli variant was not associated with a higher infection rate or higher prevalence. Furthermore, the local variant was successfully neutralized by sera from fully vaccinated individuals at a comparable level to the B.1.1.7 variant and an Israel wild-type strain. While it is not a variant of concern, routine monitoring by sequencing is still required.

SARS-CoV-2 has become a major global concern as of December 2019, particularly affecting healthcare workers. As person-to-person transmission is airborne, crowded closed spaces have high potential for rapid virus spread, especially early in the pandemic when social distancing and mask wearing were not mandatory. This retrospective study thoroughly investigates a small-scale SARS-CoV-2 outbreak in Israel’s central virology laboratory (ICVL) in mid-March 2020, in which six staff members and two related family members were infected. Suspicions regarding infection by contaminated surfaces in ICVL facilities were nullified by SARS-CoV-2 negative real time polymerase chain reaction (PCR) of work surfaces swipe tests. Complete SARS-CoV-2 genomes were sequenced and mutation analyses showed inclusion of all samples to clades 20B and 20C, possessing the spike mutation D614G. Phylogenetic analysis clarified transmission events, confirming S1 as having infected at least three other staff members and refuting the association of a staff member’s infected spouse with the ICVL transmission cluster. Finally, serology tests exhibited IgG and IgA antibodies in all infected individuals and revealed the occurrence of asymptomatic infections in additional staff members. This study demonstrates the advantages of molecular epidemiology in elucidating transmission events and exemplifies the importance of good laboratory practice, distancing and mask wearing in preventing SARS-CoV-2 spread, specifically in healthcare facilities.

Characteristics of hepatitis B (HBV) and delta (HDV) coinfection in various geographical regions, including Israel, remain unclear. Here we studied HDV seroprevalence in Israel, assessed HDV/HBV viral loads, circulating genotypes and hepatitis delta antigen (HDAg) conservation. Serological anti HDV IgG results from 8969 HBsAg positive individuals tested in 2010-2015 were retrospectively analyzed to determine HDV seroprevalence. In a cohort of HBV/HDV coinfected (n=58) and HBV monoinfected (n=27) patients, quantitative real-time PCR (qRT-PCR) and sequencing were performed to determine viral loads, genotypes and hepatitis delta antigen (HDAg) protein sequence. 6.5% (587/8969) of the HBsAg positive patients were positive for anti HDV antibodies. HDV viral load was >2 log copies/ml higher than HBV viral load in most of the coinfected patients with detectable HDV RNA (86%, 50/58). HDV genotype 1 was identified in all patients, most of whom did not express HBV. While 66.6% (4/6) of the HBV/HDV co-expressing patients carried HBV-D2 only 18.5% (5/27) of the HBV monoinfections had HBV-D2 (p=0.03). Higher genetic variability in the HDAg protein sequence was associated with higher HDV viral load. The overall significant prevalence of HDV (6.5%) mandates HDV RNA testing for all coinfected patients. Patients positive for HDV RNA (characterized by low HBV DNA blood levels) carried HDV genotype 1. Taken together, the significant HDV seroprevalence and the lack of effective anti-HDV therapy, necessitates strict clinical surveillance especially in patients with higher HDV viral loads and increased viral evolution.

In this report, we describe a national-scale monitoring of the SARS-CoV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of 13 wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19/A20 or B.1.1.7 and tested each sample for the presence and relative viral RNA load of each variant. We show that between December 2020 and March 2021, a complete shift in the SC-2 variant circulation was observed, where the B.1.1.7 replaced the A19 in all examined test points. We further show that the normalized viral load (NVL) values and the average new cases per week reached a peak in January 2021 and then decreased gradually in almost all test points, in parallel with the progression of the national vaccination campaign, during February–March 2021. This study demonstrates the importance of monitoring SC-2 variant by using a combination of inclusive and selective PCR tests on a national scale through wastewater sampling, which is far more amendable for high-throughput monitoring compared with sequencing. This approach may be useful for real-time dynamics surveillance of current and future variants, such as the Omicron (BA.1, BA.2) and other variants.

Between 2018 and 2019, Israel experienced one of its largest measles outbreaks in recent decades, with over 4300 reported cases and more than 100 documented importation events. Despite high national vaccination coverage, the prolonged nature of the outbreak posed a risk to the country’s measles elimination status. Traditional epidemiological investigations and genotyping based on the N450 region lacked sufficient resolution to differentiate between sustained local transmission and multiple independent introductions. To address this, we performed whole-genome sequencing on 123 measles virus samples representing both imported and locally acquired cases from diverse geographic regions. Phylogenetic analysis revealed multiple, distinct transmission chains, several of which could be linked to separate importation events. The MF non-coding region (MF-NCR) not only showed the highest genetic variability, but also contained many of the phylogenetic cluster-defining mutations, though informative changes were found throughout the whole genome. These findings demonstrate the value of whole-genome sequencing in resolving complex transmission dynamics and highlight the importance of integrating genomic epidemiology into routine measles surveillance. Such integration can enhance outbreak investigations and better inform public health responses to protect elimination status.

Between late 2023 and early 2024, two measles outbreaks occurred in Israel, each caused by importation of measles virus strains of respective B3 and D8 genotypes. In this study, we validate transmission pathways uncovered by epidemiological investigations using a rapid molecular approach, based on complete measles virus genomes. The presented findings support this rapid molecular approach in complementing conventional contact tracing and highlight its potential for informing public health interventions.