The city-wide full-scale interactive application of sewage surveillance programme for assisting real-time COVID-19 pandemic control - A case study in Hong Kong.

The paper discusses the implementation of Hong Kong's tailor-made sewage surveillance programme led by the Government, which has demonstrated how an efficient and well-organized sewage surveillance system can complement conventional epidemiological surveillance to facilitate the planning of intervention strategies and actions for combating COVID-19 pandemic in real-time. This included the setting up of a comprehensive sewerage network-based SARS-CoV-2 virus surveillance programme with 154 stationary sites covering 6 million people (or 80 % of the total population), and employing an intensive monitoring programme to take samples from each stationary site every 2 days. From 1 January to 22 May 2022, the daily confirmed case count started with 17 cases per day on 1 January to a maximum of 76,991 cases on 3 March and dropped to 237 cases on 22 May. During this period, a total of 270 "Restriction-Testing Declaration" (RTD) operations at high-risk residential areas were conducted based on the sewage virus testing results, where over 26,500 confirmed cases were detected with a majority being asymptomatic. In addition, Compulsory Testing Notices (CTN) were issued to residents, and the distribution of Rapid Antigen Test kits was adopted as alternatives to RTD operations in areas of moderate risk. These measures formulated a tiered and cost-effective approach to combat the disease in the local setting. Some ongoing and future enhancement efforts to improve efficacy are discussed from the perspective of wastewater-based epidemiology. Forecast models on case counts based on sewage virus testing results were also developed with R2 of 0.9669-0.9775, which estimated that up to 22 May 2022, around 2,000,000 people (~67 % higher than the total number of 1,200,000 reported to the health authority, due to various constraints or limitations) had potentially contracted the disease, which is believed to be reflecting the real situation occurring in a highly urbanized metropolis like Hong Kong.

Use of Sewage Surveillance for COVID-19: A Large-Scale Evidence-Based Program in Hong Kong.

BACKGROUND: Sewage surveillance, by detecting SARS-CoV-2 virus circulation at the community level, has the potential to supplement individual surveillance for COVID-19. However, to date, there have been no reports about the large-scale implementation and validation of sewage surveillance for public health action. OBJECTIVE: Here, we developed a standardized approach for SARS-CoV-2 detection in sewage and applied it prospectively to supplement public health interventions. METHODS: We analyzed 1,169 sewage samples collected at 492 sites from December 2020 to March 2021. Forty-seven of 492 sites tested positive, 44 (94%) of them had traceable sources of viral signals in the corresponding sewershed, either from previously unsuspected but subsequently confirmed patients or recently convalescent patients or from both patient groups. RESULTS: Sewage surveillance had a sensitivity of 54%, a specificity of 95%, a positive predictive value of 53%, and a negative predictive value of 95% for identifying a previously unsuspected patient within a sewershed. Sewage surveillance in Hong Kong provided a basis for the statutory public health action to detect silent COVID-19 transmission. DISCUSSION: Considering the epidemiological data together with the sewage testing results, compulsory testing was conducted for individual residents at 27 positive sewage sites and uncovered total of 62 previously unsuspected patients, demonstrating the value of sewage surveillance in uncovering previously unsuspected patients in the community. Our study suggests that sewage surveillance could be a powerful management tool for the control of COVID-19. https://doi.org/10.1289/EHP9966.

Hepatitis C is associated with perturbation of intrahepatic myeloid and plasmacytoid dendritic cell function.

BACKGROUND/AIMS: In most cases infection with hepatitis C results in chronic infection as a consequence of viral subversion and failed anti-viral immune responses. The suggestion that dendritic cells are defective in chronic HCV infection led us to investigate the phenotype and function of liver-derived myeloid (mDC) and plasmacytoid (pDC) dendritic cells in patients with chronic HCV infection. METHODS: Liver DCs were isolated without expansion in cytokines from human liver allowing us to study unmanipulated tissue-resident DCs ex vivo. RESULTS: Compared with mDCs isolated from non-infected inflamed liver mDCs from HCV-infected liver (a) demonstrated higher expression of MHC class II, CD86 and CD123, (b) were more efficient stimulators of allogeneic T-cells and (c) secreted less IL-10. Reduced IL-10 secretion may be a factor in the enhanced functional properties of mDCs from HCV infected liver because antibody depletion of IL-10 enhanced the ability of mDCs from non-infected liver to stimulate T-cells. In contrast, pDCs were present at lower frequencies in HCV-infected liver and expressed higher levels of the regulatory receptor BDCA-2. CONCLUSIONS: In HCV-infected liver the combination of enhanced mDC function and a reduced number of pDCs may contribute to viral persistence in the face of persistent inflammation.

The effect of molecular adsorbent recirculating system on pathophysiological parameters in patients with acute liver failure.

OBJECTIVE: To investigate the effect of the molecular adsorbent recirculating system (MARS) on physiological variables in patients with acute liver failure. DESIGN: A prospective, observational study of MARS in addition to standard medical therapy in the management of patients presenting with acute liver failure. SETTING: A regional liver transplant centre. PATIENTS: Ten consecutive patients admitted with acute liver failure with a grade III or IV hepatic encephalopathy. INTERVENTIONS: MARS therapy for 8 h on 2 consecutive days. Standard monitoring included the use of a pulmonary artery catheter and an intracranial pressure monitor. MEASUREMENTS AND RESULTS: During the first MARS treatment there was a significant increase in systemic vascular resistance index (SVRI) from 1114+/-196 to 1432+/-245 dyne s(-1) cm(-5) m(-2) with a reduction in cardiac index from 5.5+/-0.6 to 4.2+/-0.4 l min(-1) m(-2). The changes were maintained between the start of the first and second sessions but not to the end of second. Significant clearance of urea and creatinine was observed. Intracranial pressure did not change during the treatments. Overall mortality was 70%. CONCLUSIONS: MARS therapy was well tolerated, with significant increases in vascular tone during the first session. This increase was not sustained over the duration of the study with a return to baseline values by the end of the second session. Based on our experience we cannot recommend the routine use of MARS therapy in acute liver failure outside of a clinical trial.