Coordination of SARS-CoV-2 wastewater and clinical testing of university students demonstrates the importance of sampling duration and collection time.

Wastewater surveillance has been a useful tool complementing clinical testing during the COVID-19 pandemic. However, transitioning surveillance approaches to small populations, such as dormitories and assisted living facilities poses challenges including difficulties with sample collection and processing. Recently, the need for reliable and timely data has coincided with the need for precise local forecasting of the trajectory of COVID-19. This study compared wastewater and clinical data from the University of Delaware (Fall 2020 and Spring 2021 semesters), and evaluated wastewater collection practices for enhanced virus detection sensitivity. Fecal shedding of SARS-CoV-2 is known to occur in infected individuals. However, shedding concentrations and duration has been shown to vary. Therefore, three shedding periods (14, 21, and 30 days) were presumed and included for analysis of wastewater data. SARS-CoV-2 levels detected in wastewater correlated with clinical virus detection when a positive clinical test result was preceded by fecal shedding of 21 days (p< 0.05) and 30 days (p < 0.05), but not with new cases (p = 0.09) or 14 days of shedding (p = 0.17). Discretely collected wastewater samples were compared with 24-hour composite samples collected at the same site. The discrete samples (n = 99) were composited examining the influence of sampling duration and time of day on SARS-CoV-2 detection. SARS-CoV-2 detection varied among dormitory complexes and sampling durations of 3-hour, 12-hour, and 24-hour (controls). Collection times frequently showing high detection values were between the hours of 03:00 to 05:00 and 23:00 to 08:00. In each of these times of day 33% of samples (3/9) were significantly higher (p < 0.05) than the control sample. The remainder (6/9) of the collection times (3-hour and 12-hour) were not different (p > 0.05) from the control. This study provides additional framework for continued methodology development for microbiological wastewater surveillance as the COVID-19 pandemic progresses and in preparation for future epidemiological efforts.

Protection afforded by avian influenza vaccination programmes consisting of a novel RNA particle and an inactivated avian influenza vaccine against a highly pathogenic avian influenza virus challenge in layer chickens up to 18 weeks post-vaccination.

The efficacies of an oil adjuvanted-inactivated reverse genetics-derived H5 avian influenza virus (AIV) vaccine and an alphavirus replicon RNA particle (RP) AIV vaccine were evaluated in commercial Leghorn chickens. Challenge utilized A/turkey/MN/12582/2015, an isolate representing the U.S. H5N2 Clade 2.3.4.4 responsible for the 2015 highly pathogenic avian influenza (HPAI) epornitic in commercial poultry the United States. As part of a long-term, 36-week study, chickens were challenged at seven weeks of age after receiving a single vaccination, at 18 weeks of age following a vaccine prime-single boost, and at 36 weeks of age after a prime- double-boost. All vaccine programmes reduced virus oropharyngeal and cloacal shedding and mortality compared to the non-vaccinated control birds; however, chickens receiving at least one administration of the RP vaccine generally had diminished viral shedding especially from the cloacal swabbings. A detectable serum antibody response and protection were observed through 18 weeks post-vaccination. Our data suggest that, in conjunction with a comprehensive eradication, enhanced biosecurity and controlled marketing plan, vaccination programmes of commercial layer chickens with novel RP vaccines may represent an important tool for preventing HPAI-related mortalities and decreasing viral load during a catastrophic influenza outbreak. RESEARCH HIGHLIGHTS Immunization of poultry following a vaccination schedule consisting of inactivated and RNA particle vaccines offered significant protection against lethal disease following HPAIV challenge. Virus shedding was significantly (P < 0.05) reduced in chickens vaccinated with either inactivated and/or recombinant vaccines. Serum antibody titres were not a reliable indicator of protection. An inactivated vaccine containing 384 HAU of the homologous antigen was unable to induce complete protection.