Combining wastewater surveillance and case data in estimating the time-varying effective reproduction number

Wastewater surveillance has been increasingly acknowledged as a useful tool for monitoring transmission dynamics of infections of public health concern, including the coronavirus disease (COVID-19). While a range of models have been proposed to estimate the time-varying effective reproduction number (Rt) utilizing clinical data, few have harnessed the viral concentration in wastewater samples to do so, leaving uncertainties about the potential precision gains with its use. In this study, we developed a Bayesian hierarchical model which simultaneously reconstructed the latent infection trajectory and estimated Rt. Focusing on the 2022 and early 2023 COVID-19 transmission trends in Singapore, where mass community wastewater surveillance has become routine, we performed estimations using a spectrum of data sources, including reported case counts, hospital admissions, deaths, and wastewater viral loads. We further explored the performance of our wastewater model across various scenarios with different sampling strategies. The results showed consistent estimates derived from models employing diverse data streams, while models incorporating more wastewater samples exhibited greater uncertainty and variation in the inferred Rts. Additionally, our analysis revealed prominent day-of-the-week effect in reported case counts and substantial temporal variations in ascertainment rates. In response to these findings, we advocate for a hybrid approach leveraging both clinical and wastewater surveillance data to account for changes in case-ascertainment rates. Furthermore, our study demonstrates the possibility of reducing sampling frequency or sample size without compromising estimation accuracy for Rt, highlighting the potential for optimizing resource allocation in surveillance efforts while maintaining robust insights into the transmission dynamics of infectious diseases.

Case report: Zika surveillance complemented with wastewater and mosquito testing

BACKGROUND

In June 2023, a local cluster of 15 Zika cases was reported in a neighbourhood in Northeastern Singapore. The last significant local transmission of Zika virus (ZIKV) with more than 450 cases was in 2016-2017. To monitor the situation and mitigate further transmission, case, entomological and wastewater-based surveillance were carried out.

METHODS

Primary healthcare practitioners and the community were alerted to encourage timely case identification. Surveillance was enhanced through testing of Aedes mosquitoes collected from the National Gravitrap surveillance system, and wastewater samples were collected from a network of autosamplers deployed at manholes across the country.

FINDINGS

ZIKV RNA was detected in mosquito pools (3/43; 7%) and individual mosquitoes (3/82; 3.7%) captured, and in wastewater samples (13/503) collected from the vicinity of the cluster of cases. Respective samples collected from other sites across the country were negative. The peak detection of ZIKV RNA in mosquitoes and wastewater coincided temporally with the peak in the number of cases in the area (15-25 May 2023).

INTERPRETATION

The restriction of ZIKV signals from wastewater and mosquitoes within the neighbourhood suggested limited ZIKV transmission. The subsequent waning of signals suggested effectiveness of control measures. We demonstrate the utility of wastewater-based surveillance of ZIKV, which complements existing case- and entomological-based surveillance. The non-intrusive approach is particularly useful to monitor diseases such as Zika, which generally causes silent or mild infections, but may cause severe outcomes such as congenital Zika syndrome.

FUNDING

This study was funded by Singapore's Ministry of Finance and the National Environment Agency, Singapore.

Estimating COVID-19 cases on a university campus based on Wastewater Surveillance using machine learning regression models

Wastewater Surveillance (WS) is a crucial tool in the management of COVID-19 pandemic. The surveillance is based on enumerating SARS-CoV-2 RNA concentrations in the community's sewage. In this study, we used WS data to develop a regression model for estimating the number of active COVID-19 cases on a university campus. Eight univariate and multivariate regression model types i.e. Linear Regression (LM), Polynomial Regression (PR), Generalised Additive Model (GAM), Locally Estimated Scatterplot Smoothing Regression (LOESS), K Nearest Neighbours Regression (KNN), Support Vector Regression (SVR), Artificial Neural Networks (ANN) and Random Forest (RF) were developed and compared. We found that the multivariate RF regression model, was the most appropriate for predicting the prevalence of COVID-19 infections at both a campus level and hostel-level. We also found that smoothing the normalised SARS-CoV-2 data and employing multivariate modelling, using student population as a second independent variable, significantly improved the performance of the models. The final RF campus level model showed good accuracy when tested using previously unseen data; correlation coefficient of 0.97 and a mean absolute error (MAE) of 20 %. In summary, our non-intrusive approach has the ability to complement projections based on clinical tests, facilitating timely follow-up and response.

Positive association of SARS-CoV-2 RNA concentrations in wastewater and reported COVID-19 cases in Singapore - A study across three populations

Wastewater testing of SARS-CoV-2 has been adopted globally and has shown to be a useful, non-intrusive surveillance method for monitoring COVID-19 trends. In Singapore, wastewater surveillance has been widely implemented across various sites and has facilitated timely COVID-19 management and response. From April 2020 to February 2022, SARS-CoV-2 RNA concentrations in wastewater monitored across three populations, nationally, in the community, and in High Density Living Environments (HDLEs) were aggregated into indices and compared with reported COVID-19 cases and hospitalisations. Temporal trends and associations of these indices were compared descriptively and quantitatively, using Poisson Generalised Linear Models and Generalised Additive Models. National vaccination rates and vaccine breakthrough infection rates were additionally considered as confounders to shedding. Fitted models quantified the temporal associations between the indices and cases and COVID-related hospitalisations. At the national level, the wastewater index was a leading indicator of COVID-19 cases (p-value <0.001) of one week, and a contemporaneous association with hospitalisations (p-value <0.001) was observed. At finer levels of surveillance, the community index was observed to be contemporaneously associated with COVID-19 cases (p-value <0.001) and had a lagging association of 1-week in HDLEs (p-value <0.001). These temporal differences were attributed to differences in testing routines for different sites during the study period and the timeline of COVID-19 progression in infected persons. Overall, this study demonstrates the utility of wastewater surveillance in understanding underlying COVID-19 transmission and shedding levels, particularly for areas with falling or low case ascertainment. In such settings, wastewater surveillance showed to be a lead indicator of COVID-19 cases. The findings also underscore the potential of wastewater surveillance for monitoring other infectious diseases threats.

Field trial assessing the antimicrobial decontamination efficacy of gaseous ozone in a public bus setting

The widespread COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) necessitated measures aimed at preventing the spread of SARS-CoV-2. To mitigate the risk of fomite-mediated transmission, environmental cleaning and disinfection regimes have been widely implemented. However, conventional cleaning approaches such as surface wipe downs can be laborious and more efficient and effective disinfecting technologies are needed. Gaseous ozone disinfection is one technology which has been shown to be effective in laboratory studies. Here, we evaluated its efficacy and feasibility in a public bus setting, using murine hepatitis virus (a related betacoronavirus surrogate) and the bacteria Staphylococcus aureus as test organisms. An optimal gaseous ozone regime resulted in a 3.65-log reduction of murine hepatitis virus and a 4.73-log reduction of S. aureus, and decontamination efficacy correlated with exposure duration and relative humidity in the application space. These findings demonstrated gaseous ozone disinfection in field settings which can be suitably translated to public and private fleets that share analogous characteristics.

Viable mpox virus in the environment of a patient room

We conducted a prospective environmental surveillance study to investigate the air, surface, dust and water contamination of a room occupied by a patient infected with mpox virus (MPXV) at various stages of the illness. The patient tested positive for MPXV from a throat swab and skin lesions. Environmental sampling was conducted in a negative pressure room with 12 unidirectional HEPA air changes per hour and daily cleaning of the surfaces. A total of 179 environmental samples were collected on days 7, 8, 13, and 21 of illness. Among the days of sampling, air, surface, and dust contamination showed highest contamination rates on day 7 and 8 of illness, with a gradual decline to the lowest contamination level by day 21. Viable MPXV was isolated from surfaces and dust samples and no viable virus was isolated from the air and water samples.

Wastewater surveillance of SARS-CoV-2 and chemical markers in campus dormitories in an evolving COVID - 19 pandemic

In this study, we report the implementation of a comprehensive wastewater surveillance testing program at a university campus in Singapore to identify Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infected individuals and the usage of pharmaceuticals and personal care products (PPCPs) as well as other emerging contaminants (ECs). This unique co-monitoring program simultaneously measured SARS-CoV-2 with chemical markers/contaminants as the COVID-19 situation evolved from pandemic to endemic stages, following a nationwide mass vaccination drive. SARS-CoV-2 RNA concentrations in wastewater from campus dormitories were measured using real-time reverse transcription-polymerase chain reaction (RT-qPCR) and corroborated with the number of symptomatic COVID-19 cases confirmed with the antigen rapid test (ART). Consistent results were observed where the concentrations of SARS-CoV-2 RNA detected in wastewater increased proportionately with the number of COVID-19 infected individuals residing on campus. Similarly, a wide range of ECs, including disinfectants and antibiotics, were detected through sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) techniques to establish PPCPs consumption patterns during various stages of the COVID-19 pandemic in Singapore. Statistical correlation of SARS-CoV-2 RNA was observed with few ECs belonging to disinfectants, PCPs and antibiotics. A high concentration of disinfectants and subsequent positive correlation with the number of reported cases on the university campus indicates that disinfectants could serve as a chemical marker during such unprecedented times.

Rapid Diagnostic Tests for the Detection of the Four Dengue Virus Serotypes in Clinically Relevant Matrices

The efficient and accurate diagnosis of dengue, a major mosquito-borne disease, is of primary importance for clinical care, surveillance, and outbreak control. The identification of specific dengue virus serotype 1 (DENV-1) to DENV-4 can help in understanding the transmission dynamics and spread of dengue disease. The four rapid low-resource serotype-specific dengue tests use a simple sample preparation reagent followed by reverse transcription-isothermal recombinase polymerase amplification (RT-RPA) combined with lateral flow detection (LFD) technology. Results are obtained directly from clinical sample matrices in 35 min, requiring only a heating block and pipettes for liquid handling. In addition, we demonstrate that the rapid sample preparation step inactivates DENV, improving laboratory safety. Human plasma and serum were spiked with DENV, and DENV was detected with analytical sensitivities of 333 to 22,500 median tissue culture infectious doses (TCID₅₀)/mL. The analytical sensitivities in blood were 94,000 to 333,000 TCID₅₀/mL. Analytical specificity testing confirmed that each test could detect multiple serotype-specific strains but did not respond to strains of other serotypes, closely related flaviviruses, or chikungunya virus. Clinical testing on 80 human serum samples demonstrated test specificities of between 94 and 100%, with a DENV-2 test sensitivity of 100%, detecting down to 0.004 PFU/μL, similar to the sensitivity of the PCR test; the other DENV tests detected down to 0.03 to 10.9 PFU/μL. Collectively, our data suggest that some of our rapid dengue serotyping tests provide a potential alternative to conventional labor-intensive RT-quantitative PCR (RT-qPCR) detection, which requires expensive thermal cycling instrumentation, technical expertise, and prolonged testing times. Our tests provide performance and speed without compromising specificity in human plasma and serum and could become promising tools for the detection of high DENV loads in resource-limited settings. IMPORTANCE The efficient and accurate diagnosis of dengue, a major mosquito-borne disease, is of primary importance for clinical care, surveillance, and outbreak control. This study describes the evaluation of four rapid low-resource serotype-specific dengue tests for the detection of specific DENV serotypes in clinical sample matrices. The tests use a simple sample preparation reagent followed by reverse transcription-isothermal recombinase polymerase amplification (RT-RPA) combined with lateral flow detection (LFD) technology. These tests have several advantages compared to RT-qPCR detection, such as a simple workflow, rapid sample processing and turnaround times (35 min from sample preparation to detection), minimal equipment needs, and improved laboratory safety through the inactivation of the virus during the sample preparation step. The low-resource formats of these rapid dengue serotyping tests have the potential to support effective dengue disease surveillance and enhance the diagnostic testing capacity in resource-limited countries with both endemic dengue and intense coronavirus disease 2019 (COVID-19) transmission.

Assessing the efficacy of male Wolbachia-infected mosquito deployments to reduce dengue incidence in Singapore: study protocol for a cluster-randomized controlled trial

BACKGROUND

Dengue is a severe environmental public health challenge in tropical and subtropical regions. In Singapore, decreasing seroprevalence and herd immunity due to successful vector control has paradoxically led to increased transmission potential of the dengue virus. We have previously demonstrated that incompatible insect technique coupled with sterile insect technique (IIT-SIT), which involves the release of X-ray-irradiated male Wolbachia-infected mosquitoes, reduced the Aedes aegypti population by 98% and dengue incidence by 88%. This novel vector control tool is expected to be able to complement current vector control to mitigate the increasing threat of dengue on a larger scale. We propose a multi-site protocol to study the efficacy of IIT-SIT at reducing dengue incidence.

METHODS/DESIGN

The study is designed as a parallel, two-arm, non-blinded cluster-randomized (CR) controlled trial to be conducted in high-rise public housing estates in Singapore, an equatorial city-state. The aim is to determine whether large-scale deployment of male Wolbachia-infected Ae. aegypti mosquitoes can significantly reduce dengue incidence in intervention clusters. We will use the CR design, with the study area comprising 15 clusters with a total area of 10.9 km², covering approximately 722,204 residents in 1713 apartment blocks. Eight clusters will be randomly selected to receive the intervention, while the other seven will serve as non-intervention clusters. Intervention efficacy will be estimated through two primary endpoints: (1) odds ratio of Wolbachia exposure distribution (i.e., probability of living in an intervention cluster) among laboratory-confirmed reported dengue cases compared to test-negative controls and (2) laboratory-confirmed reported dengue counts normalized by population size in intervention versus non-intervention clusters.

DISCUSSION

This study will provide evidence from a multi-site, randomized controlled trial for the efficacy of IIT-SIT in reducing dengue incidence. The trial will provide valuable information to estimate intervention efficacy for this novel vector control approach and guide plans for integration into national vector control programs in dengue-endemic settings.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier: NCT05505682 . Registered on 16 August 2022. Retrospectively registered.

Development of an efficient wastewater testing protocol for high-throughput country-wide SARS-CoV-2 monitoring

Wastewater-based surveillance has been widely used as a non-intrusive tool to monitor population-level transmission of COVID-19. Although various approaches are available to concentrate viruses from wastewater samples, scalable methods remain limited. Here, we sought to identify and evaluate SARS-CoV-2 virus concentration protocols for high-throughput wastewater testing. A total of twelve protocols for polyethylene glycol (PEG) precipitation and four protocols for ultrafiltration-based approaches were evaluated across two phases. The first phase entailed an initial evaluation using a small sample set, while the second phase further evaluated five protocols using wastewater samples of varying SARS-CoV-2 concentrations. Permutations in the pre-concentration, virus concentration and RNA extraction steps were evaluated. Among PEG-based methods, SARS-CoV-2 virus recovery was optimal with 1) the removal of debris prior to processing, 2) 2 h to 24 h incubation with 8% PEG at 4 °C, 3) 4000 xg or 14,000 xg centrifugation, and 4) a column-based RNA extraction method, yielding virus recovery of 42.4-52.5%. Similarly, the optimal protocol for ultrafiltration included 1) the removal of debris prior to processing, 2) ultrafiltration, and 3) a column-based RNA extraction method, yielding a recovery of 38.2%. This study also revealed that SARS-CoV-2 RNA recovery for samples with higher virus concentration were less sensitive to changes in the PEG method, but permutations in the PEG protocol could significantly impact virus yields when wastewater samples with lower SARS-CoV-2 RNA were used. Although both PEG precipitation and ultrafiltration methods resulted in similar SARS-CoV-2 RNA recoveries, the former method is more cost-effective while the latter method provided operational efficiency as it required a shorter turn-around-time (PEG precipitation, 9-23 h; Ultrafiltration, 5 h). The decision on which method to adopt will thus depend on the use-case for wastewater testing, and the need for cost-effectiveness, sensitivity, operational feasibility and scalability.

Minimizing errors in RT-PCR detection and quantification of SARS-CoV-2 RNA for wastewater surveillance

Wastewater surveillance for pathogens using reverse transcription-polymerase chain reaction (RT-PCR) is an effective and resource-efficient tool for gathering community-level public health information, including the incidence of coronavirus disease-19 (COVID-19). Surveillance of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in wastewater can potentially provide an early warning signal of COVID-19 infections in a community. The capacity of the world's environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is increasing rapidly. However, there are no standardized protocols or harmonized quality assurance and quality control (QA/QC) procedures for SARS-CoV-2 wastewater surveillance. This paper is a technical review of factors that can cause false-positive and false-negative errors in the surveillance of SARS-CoV-2 RNA in wastewater, culminating in recommended strategies that can be implemented to identify and mitigate some of these errors. Recommendations include stringent QA/QC measures, representative sampling approaches, effective virus concentration and efficient RNA extraction, PCR inhibition assessment, inclusion of sample processing controls, and considerations for RT-PCR assay selection and data interpretation. Clear data interpretation guidelines (e.g., determination of positive and negative samples) are critical, particularly when the incidence of SARS-CoV-2 in wastewater is low. Corrective and confirmatory actions must be in place for inconclusive results or results diverging from current trends (e.g., initial onset or reemergence of COVID-19 in a community). It is also prudent to perform interlaboratory comparisons to ensure results' reliability and interpretability for prospective and retrospective analyses. The strategies that are recommended in this review aim to improve SARS-CoV-2 characterization and detection for wastewater surveillance applications. A silver lining of the COVID-19 pandemic is that the efficacy of wastewater surveillance continues to be demonstrated during this global crisis. In the future, wastewater should also play an important role in the surveillance of a range of other communicable diseases.

Minimizing errors in RT-PCR detection and quantification of SARS-CoV-2 RNA for wastewater surveillance

Wastewater surveillance for pathogens using reverse transcription-polymerase chain reaction (RT-PCR) is an effective and resource-efficient tool for gathering community-level public health information, including the incidence of coronavirus disease-19 (COVID-19). Surveillance of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) in wastewater can potentially provide an early warning signal of COVID-19 infections in a community. The capacity of the world's environmental microbiology and virology laboratories for SARS-CoV-2 RNA characterization in wastewater is increasing rapidly. However, there are no standardized protocols or harmonized quality assurance and quality control (QA/QC) procedures for SARS-CoV-2 wastewater surveillance. This paper is a technical review of factors that can cause false-positive and false-negative errors in the surveillance of SARS-CoV-2 RNA in wastewater, culminating in recommended strategies that can be implemented to identify and mitigate some of these errors. Recommendations include stringent QA/QC measures, representative sampling approaches, effective virus concentration and efficient RNA extraction, PCR inhibition assessment, inclusion of sample processing controls, and considerations for RT-PCR assay selection and data interpretation. Clear data interpretation guidelines (e.g., determination of positive and negative samples) are critical, particularly when the incidence of SARS-CoV-2 in wastewater is low. Corrective and confirmatory actions must be in place for inconclusive results or results diverging from current trends (e.g., initial onset or reemergence of COVID-19 in a community). It is also prudent to perform interlaboratory comparisons to ensure results' reliability and interpretability for prospective and retrospective analyses. The strategies that are recommended in this review aim to improve SARS-CoV-2 characterization and detection for wastewater surveillance applications. A silver lining of the COVID-19 pandemic is that the efficacy of wastewater surveillance continues to be demonstrated during this global crisis. In the future, wastewater should also play an important role in the surveillance of a range of other communicable diseases.

The first nosocomial cluster of COVID-19 due to the Delta variant in a major acute-care hospital in Singapore - investigations and outbreak response

OBJECTIVES

The first large nosocomial cluster of COVID-19 in Singapore in April 2021 led to partial closure of a major acute-care hospital. We report our investigations and evaluate the effectiveness of the BNT162.b2 and mRNA1273 vaccines against the Delta variant.

METHODS

Close contacts of COVID-19 patients and the affected ward were identified and underwent surveillance for SARS-CoV-2 infection. Patient, staff and visitor cohorts were constructed and factors associated with infection evaluated. Phylogenetic analysis of patient samples was performed. Ward air exhaust filters were tested for SARS-CoV-2 virus.

RESULTS

There were 47 cases in total, comprising 29 patients, 9 staff, 6 ward visitors and 3 household contacts. All infections were of the Delta variant. Ventilation studies showed turbulent airflow and swabs from air exhaust filters were positive for SARS-Cov2. Vaccine breakthrough infections were seen in both patients and staff. Among patients, vaccination was associated with a 79% lower odds of infection with COVID-19 (adjusted OR =0.21, 95%CI 0.05-0.95) CONCLUSIONS: This cluster occurred despite an enhancement in infection control measures that the hospital had undertaken at the onset of this pandemic, but it was rapidly brought under control through case isolation, extensive contact tracing and quarantine measures, and led to enhancements in hospital personal protective equipment (PPE) use, introduction of routine rostered testing of inpatients and staff, and hospital infrastructure changes to improve ventilation within the general ward.

Non-intrusive wastewater surveillance for monitoring of a residential building for COVID-19 cases

Wastewater-based surveillance for SARS-CoV-2 has been used for the early warning of transmission or objective trending of the population-level disease prevalence. Here, we describe a new use-case of conducting targeted wastewater surveillance to complement clinical testing for case identification in a small community at risk of COVID-19 transmission. On 2 July 2020, a cluster of COVID-19 cases in two unrelated households residing on different floors in the same stack of an apartment building was reported in Singapore. After cases were conveyed to healthcare facilities and six healthy household contacts were quarantined in their respective apartments, wastewater surveillance was implemented for the entire residential block. SARS-CoV-2 was subsequently detected in wastewaters in an increasing frequency and concentration, despite the absence of confirmed COVID-19 cases, suggesting the presence of fresh case/s in the building. Phone interviews of six residents in quarantine revealed that no one was symptomatic (fever/respiratory illness). However, when nasopharyngeal swabs from six quarantined residents were tested by PCR tests, one was positive for SARS-CoV-2. The positive case reported episodes of diarrhea and the case's stool sample was also positive for SARS-CoV-2, explaining the SARS-CoV-2 spikes observed in wastewaters. After the case was conveyed to a healthcare facility, wastewaters continued to yield positive signals for five days, though with a decreasing intensity. This was attributed to the return of recovered cases, who had continued to shed the virus. Our findings demonstrate the utility of wastewater surveillance as a non-intrusive tool to monitor high-risk COVID-19 premises, which is able to trigger individual tests for case detection, highlighting a new use-case for wastewater testing.

Hepatitis C virus antigen detection is an appropriate test for screening and early diagnosis of hepatitis C virus infection in at-risk populations and immunocompromised hosts

Early diagnosis remains key for effective prevention and treatment. Unfortunately, current screening with anti-hepatitis C virus antibody (anti-HCV Ab) test may have limited utility in the diagnosis of HCV infection and reinfection. This is of special concern to at-risk population, such as immunocompromised hosts and end-stage renal failure patients on hemodialysis. HCV antigen (Ag) could be useful in identifying the ongoing infection in such clinical scenarios. Hence, we aimed to study the utility of HCV Ag testing for the diagnosis of acute and chronic hepatitis C. Of 89 samples studied, 19 were from acute hepatitis C patients who were immunocompromised or were on hemodialysis, 43 were from active chronic hepatitis C patients and 27 were from patients treated for chronic hepatitis C. All samples were tested for HCV Ag using the Abbott ARCHITECT HCV Ag assay. HCV Ag was reactive in 19/19 samples from acute hepatitis C patients and 42/43 samples from active chronic hepatitis C patients. It was nonreactive in all samples from treated patients. The test showed a sensitivity and specificity of 98.4% and 100.0%, respectively. The positive and negative predictive values were 100.0% and 96.4%, respectively. The HCV antigen test has high clinical sensitivity and specificity and is useful for the diagnosis of acute and chronic hepatitis C infection in at-risk and immunocompromised patients. Its short turnaround time and relatively low cost are advantageous for use in patients on hemodialysis and other at-risk patients who require monitoring of HCV infection and reinfection.

Evaluation of eight commercial Zika virus IgM and IgG serology assays for diagnostics and research

Several commercial Zika virus (ZIKV) serology assays have been developed since the recognition of ZIKV outbreaks as a Public Health Emergency of International Concern in 2016. However, test interpretation for ZIKV serology can be challenging due to antibody cross-reactivity with other flaviviruses like dengue virus (DENV). Therefore, we sought to evaluate the performance of eight commercially available ZIKV IgM and IgG assays across three testing platforms, namely, immunochromatographic tests (ICT), ELISAs and immunofluorescence tests (IIFT). The test panel comprised of 278 samples, including acute and convalescent sera or plasma from ZIKV-confirmed, DENV-confirmed, non-ZIKV and non-DENV patients, and residual sera from healthy blood donors. The ZIKV IgM and IgG serology assays yielded higher test sensitivities of 23.5% - 97.1% among ZIKV convalescent samples as compared to 5.6% - 27.8% among ZIKV acute samples; the test specificities were 63.3% - 100% among acute and convalescent DENV, non-DENV samples. Among the ELISAs and IIFTs, the Diapro ZIKV IgM ELISA demonstrated high test sensitivity (96%) and specificity (80%) when tested on early convalescent samples, while the Euroimmun ZIKV IgG ELISA yielded the highest test specificity of 97% - 100% on samples from non-ZIKV patients and healthy blood donors. For rapid ICTs, the LumiQuick IgM rapid ICT yielded low test sensitivity, suggesting its limited utility. We showed that commercial ZIKV IgM and IgG serology assays have differing test performances, with some having moderate to high test sensitivities and specificities when used in a dengue endemic setting, although there were limitations in IgG serology.

Standardizing data reporting in the research community to enhance the utility of open data for SARS-CoV-2 wastewater surveillance

SARS-CoV-2 RNA detection in wastewater is being rapidly developed and adopted as a public health monitoring tool worldwide. With wastewater surveillance programs being implemented across many different scales and by many different stakeholders, it is critical that data collected and shared are accompanied by an appropriate minimal amount of metainformation to enable meaningful interpretation and use of this new information source and intercomparison across datasets. While some databases are being developed for specific surveillance programs locally, regionally, nationally, and internationally, common globally-adopted data standards have not yet been established within the research community. Establishing such standards will require national and international consensus on what metainformation should accompany SARS-CoV-2 wastewater measurements. To establish a recommendation on minimum information to accompany reporting of SARS-CoV-2 occurrence in wastewater for the research community, the United States National Science Foundation (NSF) Research Coordination Network on Wastewater Surveillance for SARS-CoV-2 hosted a workshop in February 2021 with participants from academia, government agencies, private companies, wastewater utilities, public health laboratories, and research institutes. This report presents the primary two outcomes of the workshop: (i) a recommendation on the set of minimum meta-information that is needed to confidently interpret wastewater SARS-CoV-2 data, and (ii) insights from workshop discussions on how to improve standardization of data reporting.

Environmental Contamination of SARS-CoV-2 in a Non-Healthcare Setting

Fomite-mediated transmission has been identified as a possible route for the spread of COVID-19 disease caused by SARS-CoV-2. In healthcare settings, environmental contamination by SARS-CoV-2 has been found in patients’ rooms and toilets. Here, we investigated environmental presence of SARS-CoV-2 in non-healthcare settings and assessed the efficacy of cleaning and disinfection in removing virus contamination. A total of 428 environmental swabs and six air samples was taken from accommodation rooms, toilets and elevators that have been used by COVID-19 cases. By using a reverse transcription polymerase chain reaction assay, we detected two SARS-CoV-2 RNA positive samples in a room where a COVID-19 patient stayed prior to diagnosis. The present study highlights the risk of fomite-mediated transmission in non-healthcare settings and the importance of surface disinfection in spaces occupied by cases. Of note, neither air-borne transmission nor surface contamination of elevators, which were transiently exposed to infected individuals, was evident among samples analyzed.

Vaccine-associated Rubella - a report of two cases and a review of the literature

We report the clinical characteristics of two adult patients, presenting with a typical erythematous rash consistent with rubella disease after MMR vaccination. Both patients had an uncomplicated clinical course and recovered uneventfully. One patient was confirmed to have vaccine-associated rubella via sequencing of virus isolated in viral culture. The other patient had a pharyngeal swab positive for rubella virus PCR, with sequencing matching the vaccine strain. There are few reports of clinical disease from rubella vaccine-strains in the literature. Previous authors have reported severe disseminated vaccine-associated rubella in both immunodeficient and immunocompetent patients. Further study is required to ascertain the incidence, risk factors, and clinical characteristics of this condition; as well as investigate the extent of horizontal transmission to guide infection control recommendations.