The Prevalence and Clinical Implications of Rectal SARS-CoV-2 Shedding in Danish COVID-19 Patients and the General Population

Microbiological Methods Used in the Enterics for Global Health Shigella Surveillance Study

Background

Shigella is a major cause of diarrhea in young children worldwide. Multiple vaccines targeting Shigella are in development, and phase 3 clinical trials are imminent to determine efficacy against shigellosis.

Methods

The Enterics for Global Health (EFGH) Shigella surveillance study is designed to determine the incidence of medically attended shigellosis in 6- to 35-month-old children in 7 resource-limited settings. Here, we describe the microbiological methods used to isolate and identify Shigella. We developed a standardized laboratory protocol for isolation and identification of Shigella by culture. This protocol was implemented across all 7 sites, ensuring consistency and comparability of results. Secondary objectives of the study are to determine the antibiotic resistance profiles of Shigella, compare isolation of Shigella from rectal swabs versus whole stool, and compare isolation of Shigella following transport of rectal swabs in Cary-Blair versus a modified buffered glycerol saline transport medium.

Conclusions

Data generated from EFGH using culture methods described herein can potentially be used for microbiological endpoints in future phase 3 clinical trials to evaluate vaccines against shigellosis and for other clinical and public health studies focused on these organisms.

Viral shedding of SARS-CoV-2 in body fluids associated with sexual activity: a systematic review and meta-analysis

OBJECTIVE

To identify and summarise the evidence on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA detection and persistence in body fluids associated with sexual activity (saliva, semen, vaginal secretion, urine and faeces/rectal secretion).

ELIGIBILITY

All studies that reported detection of SARS-CoV-2 in saliva, semen, vaginal secretion, urine and faeces/rectal swabs.

INFORMATION SOURCES

The WHO COVID-19 database from inception to 20 April 2022.

RISK OF BIAS ASSESSMENT

The National Institutes of Health tools.

SYNTHESIS OF RESULTS

The proportion of patients with positive results for SARS-CoV-2 and the proportion of patients with a viral duration/persistence of at least 14 days in each fluid was calculated using fixed or random effects models.

INCLUDED STUDIES

A total of 182 studies with 10 023 participants.

RESULTS

The combined proportion of individuals with detection of SARS-CoV-2 was 82.6% (95% CI: 68.8% to 91.0%) in saliva, 1.6% (95% CI: 0.9% to 2.6%) in semen, 2.7% (95% CI: 1.8% to 4.0%) in vaginal secretion, 3.8% (95% CI: 1.9% to 7.6%) in urine and 31.8% (95% CI: 26.4% to 37.7%) in faeces/rectal swabs. The maximum viral persistence for faeces/rectal secretions was 210 days, followed by semen 121 days, saliva 112 days, urine 77 days and vaginal secretions 13 days. Culturable SARS-CoV-2 was positive for saliva and faeces.

LIMITATIONS

Scarcity of longitudinal studies with follow-up until negative results.

INTERPRETATION

SARS-CoV-2 RNA was detected in all fluids associated with sexual activity but was rare in semen and vaginal secretions. Ongoing droplet precautions and awareness of the potential risk of contact with faecal matter/rectal mucosa are needed.

PROSPERO REGISTRATION NUMBER

CRD42020204741.

SARS-CoV-2 Gut-Targeted Epitopes: Sequence Similarity and Cross-Reactivity Join Together for Molecular Mimicry

The gastrointestinal tract can be heavily infected by SARS-CoV-2. Being an auto-immunogenic virus, SARS-CoV-2 represents an environmental factor that might play a role in gut-associated autoimmune diseases. However, molecular mimicry between the virus and the intestinal epitopes is under-investigated. The present study aims to elucidate sequence similarity between viral antigens and human enteric sequences, based on known cross-reactivity. SARS-CoV-2 epitopes that cross-react with human gut antigens were explored, and sequence alignment was performed against self-antigens implicated in enteric autoimmune conditions. Experimental SARS-CoV-2 epitopes were aggregated from the Immune Epitope Database (IEDB), while enteric antigens were obtained from the UniProt Knowledgebase. A Pairwise Local Alignment tool, EMBOSS Matcher, was employed for the similarity search. Sequence similarity and targeted cross-reactivity were depicted between 10 pairs of immunoreactive epitopes. Similar pairs were found in four viral proteins and seven enteric antigens related to ulcerative colitis, primary biliary cholangitis, celiac disease, and autoimmune hepatitis. Antibodies made against the viral proteins that were cross-reactive with human gut antigens are involved in several essential cellular functions. The relationship and contribution of those intestinal cross-reactive epitopes to SARS-CoV-2 or its potential contribution to gut auto-immuno-genesis are discussed.

Capturing the SARS-CoV-2 infection pyramid within the municipality of Rotterdam using longitudinal sewage surveillance

Despite high vaccination rates in the Netherlands, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to circulate. Longitudinal sewage surveillance was implemented along with the notification of cases as two parts of the surveillance pyramid to validate the use of sewage for surveillance, as an early warning tool, and to measure the effect of interventions. Sewage samples were collected from nine neighborhoods between September 2020 and November 2021. Comparative analysis and modeling were performed to understand the correlation between wastewater and case trends. Using high resolution sampling, normalization of wastewater SARS-CoV-2 concentrations, and 'normalization' of reported positive tests for testing delay and intensity, the incidence of reported positive tests could be modeled based on sewage data, and trends in both surveillance systems coincided. The high collinearity implied that high levels of viral shedding around the onset of disease largely determined SARS-CoV-2 levels in wastewater, and that the observed relationship was independent of variants of concern and vaccination levels. Sewage surveillance alongside a large-scale testing effort where 58 % of a municipality was tested, indicated a five-fold difference in the number of SARS-CoV-2-positive individuals and reported cases through standard testing. Where trends in reported positive cases were biased due to testing delay and testing behavior, wastewater surveillance can objectively display SARS-CoV-2 dynamics for both small and large locations and is sensitive enough to measure small variations in the number of infected individuals within or between neighborhoods. With the transition to a post-acute phase of the pandemic, sewage surveillance can help to keep track of re-emergence, but continued validation studies are needed to assess the predictive value of sewage surveillance with new variants. Our findings and model aid in interpreting SARS-CoV-2 surveillance data for public health decision-making and show its potential as one of the pillars of future surveillance of (re)emerging viruses.

The amount of SARS-CoV-2 RNA in wastewater relates to the development of the pandemic and its burden on the health system

Virus surveillance in wastewater can be a useful indicator of the development of the COVID-19 pandemic in communities. However, knowledge about how the amount of SARS-CoV-2 RNA in wastewater relates to different data on the burden on the health system is still limited. Herein, we monitored the amount of SARS-CoV-2 RNA and the spectrum of virus variants in weekly pooled wastewater samples for two years from mid-February 2020 and compared with several clinical data. The two-year monitoring showed the weekly changes in the amount of viral RNA in wastewater preceded the hospital care needs for COVID-19 and the number of acute calls on adult acute respiratory distress by 1-2 weeks during the first three waves of COVID-19. Our study demonstrates that virus surveillance in wastewater can predict the development of a pandemic and its burden on the health system, regardless of society's test capacity and possibility of tracking infected cases.