Increased detection of Echovirus 6-associated meningitis in patients hospitalized during the COVID-19 pandemic, Israel 2021-2022.

BACKGROUND: Outbreaks of enteroviral meningitis occur periodically and may lead to hospitalization and severe disease. OBJECTIVE: To analyze and describe the meningitis outbreak in patients hospitalized in Israel in 2021-2022, during the COVID-19 pandemic. RESULTS: In December 2021, before the emergence of the SARS-CoV-2 omicron variant, an off-season increase in enterovirus (EV) infections was observed among patients hospitalized with meningitis. In January 2022, enterovirus cases decreased by 66% in parallel with the peak of the Omicron wave, and then increased rapidly by 78% in March (compared with February) after a decline in Omicron cases. Sequencing of the enterovirus-positive samples showed a dominance of echovirus 6 (E-6) (29%) before and after the Omicron wave. Phylogenetic analysis found that all 29 samples were very similar and all clustered in the E-6 C1 subtype. The main E-6 symptoms observed were fever and headache, along with vomiting and neck stiffness. The median patient age was 25 years, with a broad range (0-60 years). CONCLUSION: An upsurge in enterovirus cases was observed after the decline of the SARS-CoV-2 omicron wave. The dominant subtype was E-6, which was present prior to the emergence of the omicron variant, but increased rapidly only after the omicron wave decline. We hypothesize that the omicron wave delayed the rise in E-6-associated meningitis.

Environmental surveillance detected type 3 vaccine-derived polioviruses in increasing frequency at multiple sites prior to detection of a poliomyelitis case.

Israel conducts routine environmental (15 sites) and acute flaccid paralysis (AFP) surveillance for poliovirus. During September 2021, increasing numbers of wastewater samples collected from more than one site in the Jerusalem region proved positive for ambiguous type 3 vaccine-derived poliovirus (aVDPV3), while environmental samples from remaining sampling sites were negative. In late February 2022, a VDPV3, genetically related to the Jerusalem environmental surveillance samples, was isolated from a stool sample collected from a non-immunodeficient, non-immunized child from Jerusalem who developed AFP, indicating that the aVDPV3s were circulating (cVDPV3s) rather than immunodeficiency-related VDPV3s (iVDPVs). In response to these isolations, the Israel Ministry of Health launched a catch-up immunization program.

Emergence of genetically linked vaccine-originated poliovirus type 2 in the absence of oral polio vaccine, Jerusalem, April to July 2022.

We report an emergence and increase in poliovirus type 2 detection via routine wastewater surveillance in three non-overlapping regions in the Jerusalem region, Israel, between April and July 2022. Sequencing showed genetic linkage among isolates and accumulation of mutations over time, with two isolates defined as vaccine-derived polioviruses (VDPV). This demonstrates the emergence and potential circulation of type 2 VDPV in a high-income country with high vaccine coverage and underscores the importance of routine wastewater surveillance during the polio eradication.

Monitoring of Enterovirus D68 Outbreak in Israel by a Parallel Clinical and Wastewater Based Surveillance.

Enterovirus D68 (EVD68) was recently identified as an important cause of respiratory illness and acute flaccid myelitis (AFM), mostly in children. Here, we examined 472 pediatric patients diagnosed with severe respiratory illness and screened for EVD68 between April and October 2021. In parallel, samples collected from a wastewater treatment plant (WWTP) covering the residential area of the hospitalized patients were also tested for EVD68. Of the 472 clinical samples evaluated, 33 (7%) patients were positive for EVD68 RNA. All wastewater samples were positive for EVD68, with varying viral genome copy loads. Calculated EVD68 genome copies increased from the end of May until July 2021 and dramatically decreased at the beginning of August. A similar trend was observed in both clinical and wastewater samples during the period tested. Sequence analysis of EVD68-positive samples indicated that all samples originated from the same branch of subclade B3. This study is the first to use wastewater-based epidemiology (WBE) to monitor EVD68 dynamics by quantitative detection and shows a clear correlation with clinically diagnosed cases. These findings highlight the potential of WBE as an important tool for continuous surveillance of EVD68 and other enteroviruses.