Wastewater-based Epidemiology for COVID-19 Surveillance: A Survey.

The pandemic of COVID-19 has imposed tremendous pressure on public health systems and social economic ecosystems over the past years. To alleviate its social impact, it is important to proactively track the prevalence of COVID-19 within communities. The traditional way to estimate the disease prevalence is to estimate from reported clinical test data or surveys. However, the coverage of clinical tests is often limited and the tests can be labor-intensive, requires reliable and timely results, and consistent diagnostic and reporting criteria. Recent studies revealed that patients who are diagnosed with COVID-19 often undergo fecal shedding of SARS-CoV-2 virus into wastewater, which makes wastewater-based epidemiology (WBE) for COVID-19 surveillance a promising approach to complement traditional clinical testing. In this paper, we survey the existing literature regarding WBE for COVID-19 surveillance and summarize the current advances in the area. Specifically, we have covered the key aspects of wastewater sampling, sample testing, and presented a comprehensive and organized summary of wastewater data analytical methods. Finally, we provide the open challenges on current wastewater-based COVID-19 surveillance studies, aiming to encourage new ideas to advance the development of effective wastewater-based surveillance systems for general infectious diseases.

Use of serial testing to interrupt a severe acute respiratory coronavirus virus 2 (SARS-CoV-2) outbreak on a hospital medical floor-Minnesota, October-December 2020.

OBJECTIVE: Describe a severe acute respiratory coronavirus virus 2 (SARS-CoV-2) hospital outbreak and the role of serial testing of patients and healthcare personnel (HCP) in interrupting SARS-CoV-2 transmission. DESIGN: Outbreak investigation. SETTING: Medical floor of a tertiary-care center in Minnesota. METHODS: Serial testing for SARS-CoV-2 and whole-genome sequencing (WGS) of positive specimens from HCP and patients were used. An outbreak-associated case was defined as a positive SARS-CoV-2 molecular test in an HCP who worked on the floor prior to testing positive or in a patient who was hospitalized on the medical floor bewteen October 27 and December 1, 2020. WGS was used to determine potential routes of transmission. RESULTS: The outbreak was detected after a patient hospitalized for 12 days tested positive for SARS-CoV-2. Serial testing of patients and HCP was conducted in response. Overall, 247 HCP and 41 patients participated in serial SARS-CoV-2 testing; 52 HCP (21%) and 19 hospitalized patients (46%) tested positive. One additional HCP tested positive outside serial testing. The WGS of specimens from 27 (51%) HCP and 15 (79%) patients identified 3 distinct transmission clusters. WGS and epidemiologic evidence suggested intrafacility transmission. The proportions of asymptomatic and presymptomatic patients who tested positive (63%) and HCP who worked during their infectious period (75%) highlight the need for serial testing of asymptomatic patients and HCP during outbreaks. CONCLUSIONS: Coupled with preventive measures such as personal protective equipment use and physical distancing, serial testing of HCP and patients could help detect and prevent transmission within healthcare facilities during outbreaks and when nosocomial transmission is suspected.

Transmission of and Infection With COVID-19 Among Vaccinated and Unvaccinated Attendees of an Indoor Wedding Reception in Minnesota.

Importance: Characterizing rates of SARS-CoV-2 infection among vaccinated and unvaccinated persons with the same exposure is critical to understanding the association of vaccination with the risk of infection with the Delta variant. Additionally, evidence of Delta variant transmission by children to vaccinated adults has important public health implications. Objective: To characterize transmission and infection of SARS-CoV-2 among vaccinated and unvaccinated attendees of an indoor wedding reception. Design, Setting, and Participants: This cohort study included attendees at an indoor wedding reception in Minnesota in July 2021. Data were collected from REDCap surveys and routine surveillance interviews. The full list of attendees and a partial list of emails were obtained. Fifty-seven attendees completed the emailed survey. Eighteen additional attendees were identified from the state health department COVID-19 surveillance database. Exposures: Attendance at an indoor event. Main Outcomes and Measures: Risk of SARS-CoV-2 infection among vaccinated and unvaccinated attendees, identification of an index case, whole genome sequencing (WGS) to identify the COVID-19 variant, understanding of transmission patterns, and assessment of secondary transmission. The primary case definition was an individual with a positive SARS-CoV-2 test who attended the wedding in the 14 days prior to their illness. Results: Data were gathered for 75 attendees (mean [SE] age, 37.5 [13.7] years; 57 [76%] female individuals), of whom 56 (75%) were fully vaccinated, 4 (5%) were partially vaccinated, and 15 (20%) were unvaccinated. Of 62 attendees who were tested, 29 (47%) tested positive, including 16 of 46 fully vaccinated attendees (35%), 2 of 4 partially vaccinated attendees (50%), and 11 of 12 unvaccinated attendees (92%). Being unvaccinated was associated with a higher risk of infection compared with being vaccinated (risk ratio, 2.64; 95% CI, 1.71-4.06; P = .001). One unvaccinated adult required hospitalization. An unvaccinated child who was symptomatic on the event date was identified as the index case. Eleven specimens were available for WGS. All sequenced specimens were closely related and were identified as the Delta variant. WGS supported secondary transmission from a vaccinated individual with SARS-CoV-2. Conclusions and Relevance: This cohort study identified a COVID-19 Delta variant outbreak at an indoor event despite a high proportion of vaccinated attendees. It found that vaccination was associated with a reduced risk of infection.

COVID-19 Outbreak Associated With a Fitness Center-Minnesota, September-November 2020.

The Minnesota Department of Health investigated a coronavirus disease 2019 (COVID-19) outbreak at a fitness center in Olmsted County, Minnesota. Twenty-three severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections (5 employees and 18 members) were identified. An epidemiological investigation supported by whole genome sequencing demonstrated that transmission of SARS-CoV-2 occurred at the fitness center despite following recommended prevention strategies.

First Identified Cases of SARS-CoV-2 Variant P.1 in the United States - Minnesota, January 2021.

Since December 2020, the Minnesota Department of Health (MDH) Public Health Laboratory has been receiving 100 specimens per week (50 from each of two clinical partners) with low cycle threshold (Ct) values for routine surveillance for SARS-CoV-2, the virus that causes COVID-19. On January 25, 2021, MDH identified the SARS-CoV-2 variant P.1 in one specimen through this surveillance system using whole genome sequencing, representing the first identified case of this variant in the United States. The P.1 variant was first identified in travelers from Brazil during routine airport screening in Tokyo, Japan, in early January 2021 (1). This variant has been associated with increased transmissibility (2), and there are concerns that mutations in the spike protein receptor-binding domain might disrupt both vaccine-induced and natural immunity (3,4). As of February 28, 2021, a total of 10 P.1 cases had been identified in the United States, including the two cases described in this report, followed by one case each in Alaska, Florida, Maryland, and Oklahoma (5).

First Identified Cases of SARS-CoV-2 Variant B.1.1.7 in Minnesota - December 2020-January 2021.

On January 9, 2021, the Minnesota Department of Health (MDH) announced the identification of the SARS-CoV-2 variant of concern (VOC) B.1.1.7, also referred to as 20I/501Y.V1 and VOC 202012/01, in specimens from five persons; on January 25, MDH announced the identification of this variant in specimens from three additional persons. The B.1.1.7 variant, which is reported to be more transmissible than certain other SARS-CoV-2 lineages*,† (1), was first reported in the United Kingdom in December 2020 (1). As of February 14, 2021, a total of 1,173 COVID-19 cases of the B.1.1.7 variant had been identified in 39 U.S. states and the District of Columbia (2). Modeling data suggest that B.1.1.7 could become the predominant variant in the United States in March 2021 (3).