Wastewater surveillance in post-omicron silent phase uncovers silent waves and cryptic transmission of SARS-CoV-2 variants; a yearlong study in Western India.

Due to reduced clinical testing and evolving monitoring challenges, tracking the emergence and evolution of SARS-CoV-2 variants has become increasingly complex. To address this gap, we investigated the utility of wastewater-based epidemiology (WBE) as a complementary tool for SARS-CoV-2 variant surveillance in sewage treatment plants (STPs) across Pune, India. We analyzed 1128 wastewater samples collected between May 2022 and May 2023, using Illumina and nanopore sequencing techniques for robust detection and variant characterization. The study revealed critical findings, including "silent waves" with elevated viral load despite minimal clinical cases, suggesting potential cryptic transmission. These silent waves aligned with the dominance of Omicron BA.2 in June-July 2022 and emergence of the recombinant XBB clade in December 2022. Importantly, sequencing detected XBB lineages 130-253 days before their initial clinical identification, demonstrating its significant advantage in early variant detection. Furthermore, wastewater analysis revealed a higher degree of lineage diversity compared to clinical data, indicating its ability to capture a broader spectrum of circulating variants. The BA.2.86.X was identified 103 days prior to its clinical detection in Pune, highlighting WBE's remarkable lead time. Surprisingly, BF.7.X and BQ.X fragments were also detected in wastewater but not yet reported clinically. These findings demonstrate the remarkable value of WBE as an early warning tool for SARS-CoV-2 variants ahead of time. By revealing silent waves, enabling early variant detection, and capturing a broader viral spectrum, WBE effort could empower public health officials to make informed decisions and implement effective strategies to mitigate future waves, especially in contexts with declining clinical testing.

Rajput V ，Pramanik R ，Nannaware K ，Malik V ，Matra S ，Kumar S ，Joshi S ，Kadam P ，Bhalerao U ，Tupekar M ，Deshpande D ，Shah P ，Sangewar P ，Gogate N ，Boargaonkar R ，Patil D ，Kale S ，Bhalerao A ，Jain N ，Shashidhara LS ，Kamble S ，Dastager S ，Karmodiya K ，Dharne M ... -  《-》

Genomic surveillance reveals early detection and transition of delta to omicron lineages of SARS-CoV-2 variants in wastewater treatment plants of Pune, India.

The COVID-19 pandemic has emphasized the urgency for rapid public health surveillance methods to detect and monitor the transmission of infectious diseases. The wastewater-based epidemiology (WBE) has emerged as a promising tool for proactive analysis and quantification of infectious pathogens within a population before clinical cases emerge. In the present study, we aimed to assess the trend and dynamics of SARS-CoV-2 variants using a longitudinal approach. Our objective included early detection and monitoring of these variants to enhance our understanding of their prevalence and potential impact. To achieve our goals, we conducted real-time quantitative polymerase chain reaction (RT-qPCR) and Illumina sequencing on 442 wastewater (WW) samples collected from 10 sewage treatment plants (STPs) in Pune city, India, spanning from November 2021 to April 2022. Our comprehensive analysis identified 426 distinct lineages representing 17 highly transmissible variants of SARS-CoV-2. Notably, fragments of Omicron variant were detected in WW samples prior to its first clinical detection in Botswana. Furthermore, we observed highly contagious sub-lineages of the Omicron variant, including BA.1 (~28%), BA.1.X (1.0-72%), BA.2 (1.0-18%), BA.2.X (1.0-97.4%) BA.2.12 (0.8-0.25%), BA.2.38 (0.8-1.0%), BA.2.75 (0.01-0.02%), BA.3 (0.09-6.3%), BA.4 (0.24-0.29%), and XBB (0.01-21.83%), with varying prevalence rates. Overall, the present study demonstrated the practicality of WBE in the early detection of SARS-CoV-2 variants, which could help track future outbreaks of SARS-CoV-2. Such approaches could be implicated in monitoring infectious agents before they appear in clinical cases.

Rajput V ，Pramanik R ，Malik V ，Yadav R ，Samson R ，Kadam P ，Bhalerao U ，Tupekar M ，Deshpande D ，Shah P ，Shashidhara LS ，Boargaonkar R ，Patil D ，Kale S ，Bhalerao A ，Jain N ，Kamble S ，Dastager S ，Karmodiya K ，Dharne M ... -  《-》

Wastewater Genomic Surveillance Captures Early Detection of Omicron in Utah.

Gupta P ，Liao S ，Ezekiel M ，Novak N ，Rossi A ，LaCross N ，Oakeson K ，Rohrwasser A ... -  《Microbiology Spectrum》

Baseline Sequencing Surveillance of Public Clinical Testing, Hospitals, and Community Wastewater Reveals Rapid Emergence of SARS-CoV-2 Omicron Variant of Concern in Arizona, USA.

Smith MF ，Holland SC ，Lee MB ，Hu JC ，Pham NC ，Sullins RA ，Holland LA ，Mu T ，Thomas AW ，Fitch R ，Driver EM ，Halden RU ，Villegas-Gold M ，Sanders S ，Krauss JL ，Nordstrom L ，Mulrow M ，White M ，Murugan V ，Lim ES ... -  《mBio》

Rapid and extensive SARS-CoV-2 Omicron variant infection wave revealed by wastewater surveillance in Shenzhen following the lifting of a strict COVID-19 strategy.

Wastewater-based epidemiology (WBE) has emerged as a promising tool for monitoring the spread of COVID-19, as SARS-CoV-2 can be shed in the faeces of infected individuals, even in the absence of symptoms. This study aimed to optimize a prediction model for estimating COVID-19 infection rates based on SARS-CoV-2 RNA concentrations in wastewater, and reveal the infection trends and variant diversification in Shenzhen, China following the lifting of a strict COVID-19 strategy. Faecal samples (n = 4337) from 1204 SARS-CoV-2 infected individuals hospitalized in a designated hospital were analysed to obtain Omicron variant-specific faecal shedding dynamics. Wastewater samples from 6 wastewater treatment plants (WWTPs) and 9 pump stations, covering 3.55 million people, were monitored for SARS-CoV-2 RNA concentrations and variant abundance. We found that the viral load in wastewater increased rapidly in December 2022 in the two districts, demonstrating a sharp peak in COVID-19 infections in late-December 2022, mainly caused by Omicron subvariants BA.5.2.48 and BF.7.14. The prediction model, based on the mass balance between total viral load in wastewater and individual faecal viral shedding, revealed a surge in the cumulative infection rate from <0.1 % to over 70 % within three weeks after the strict COVID-19 strategy was lifted. Additionally, 39 cryptic SARS-CoV-2 variants were identified in wastewater, in addition to those detected through clinical surveillance. These findings demonstrate the effectiveness of WBE in providing comprehensive and efficient assessments of COVID-19 infection rates and identifying cryptic variants, highlighting its potential for monitoring emerging pathogens with faecal shedding.

Li Y ，Du C ，Lv Z ，Wang F ，Zhou L ，Peng Y ，Li W ，Fu Y ，Song J ，Jia C ，Zhang X ，Liu M ，Wang Z ，Liu B ，Yan S ，Yang Y ，Li X ，Zhang Y ，Yuan J ，Xu S ，Chen M ，Shi X ，Peng B ，Chen Q ，Qiu Y ，Wu S ，Jiang M ，Chen M ，Tang J ，Wang L ，Hu L ，Wei B ，Xia Y ，Ji JS ，Wan C ，Lu H ，Zhang T ，Zou X ，Fu S ，Hu Q ... -  《-》