This study, conducted in Leuven, Belgium, over a 2-year period, investigates the use of wastewater sampling to monitor the circulation of respiratory viruses. The researchers collected weekly wastewater samples from a regional treatment plant and used an in-house multiplex quantitative PCR respiratory panel to detect various respiratory pathogens. The study compared these wastewater data with clinical samples from University Hospitals Leuven (UZL) to assess the correlation between wastewater and clinical findings. Key findings include: - **Influenza A**: Wastewater data aligned with clinical samples, showing a peak in mid-February to mid-May 2022. - **Respiratory Syncytial Virus (RSV)**: Wastewater detected RSV peaks in March-July 2021 and November-December 2022, corresponding to clinical data. - **Human Metapneumovirus (HMPV)**: HMPV was consistently detected in wastewater from late September 2021 to late October 2022, coinciding with high clinical cases. - **Parainfluenzavirus (PIV)**: PIV-1 was detected in wastewater during fall 2022, while PIV-2 and PIV-3 were sporadically detected. - **Adenovirus and Human Bocavirus (HBoV)**: These viruses were consistently detected in wastewater, indicating their presence in the community, even though clinical cases were low. - **Enterovirus D68 (EV-D68)**: EV-D68 was detected in wastewater during early September to December 2021, aligning with a regional outbreak. - **Human Parechovirus (HPEV)**: HPEV was consistently detected in wastewater but had few clinical positives, suggesting it may be associated with enteric infections. - **SARS-CoV-2**: Detection of SARS-CoV-2 began in late September 2021, reflecting community circulation during the pandemic. The study concludes that wastewater sampling is a valuable tool for monitoring respiratory virus circulation at the population level, providing early warning signals and enhancing public health efforts.This study, conducted in Leuven, Belgium, over a 2-year period, investigates the use of wastewater sampling to monitor the circulation of respiratory viruses. The researchers collected weekly wastewater samples from a regional treatment plant and used an in-house multiplex quantitative PCR respiratory panel to detect various respiratory pathogens. The study compared these wastewater data with clinical samples from University Hospitals Leuven (UZL) to assess the correlation between wastewater and clinical findings. Key findings include: - **Influenza A**: Wastewater data aligned with clinical samples, showing a peak in mid-February to mid-May 2022. - **Respiratory Syncytial Virus (RSV)**: Wastewater detected RSV peaks in March-July 2021 and November-December 2022, corresponding to clinical data. - **Human Metapneumovirus (HMPV)**: HMPV was consistently detected in wastewater from late September 2021 to late October 2022, coinciding with high clinical cases. - **Parainfluenzavirus (PIV)**: PIV-1 was detected in wastewater during fall 2022, while PIV-2 and PIV-3 were sporadically detected. - **Adenovirus and Human Bocavirus (HBoV)**: These viruses were consistently detected in wastewater, indicating their presence in the community, even though clinical cases were low. - **Enterovirus D68 (EV-D68)**: EV-D68 was detected in wastewater during early September to December 2021, aligning with a regional outbreak. - **Human Parechovirus (HPEV)**: HPEV was consistently detected in wastewater but had few clinical positives, suggesting it may be associated with enteric infections. - **SARS-CoV-2**: Detection of SARS-CoV-2 began in late September 2021, reflecting community circulation during the pandemic. The study concludes that wastewater sampling is a valuable tool for monitoring respiratory virus circulation at the population level, providing early warning signals and enhancing public health efforts.