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Background:The risk of environmental contamination by severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in the intensive care unit (ICU) is unclear. We evaluated the extent of environmental contamination in the ICU and correlated this with patient and disease factors, including the impact of different ventilatory modalities.Methods:In this observational study, surface environmental samples collected from ICU patient rooms and common areas were tested for SARS-CoV-2 by polymerase chain reaction (PCR). Select samples from the common area were tested by cell culture. Clinical data were collected and correlated to the presence of environmental contamination. Results were compared to historical data from a previous study in general wards.Results:In total, 200 samples from 20 patient rooms and 75 samples from common areas and the staff pantry were tested. The results showed that 14 rooms had at least 1 site contaminated, with an overall contamination rate of 14% (28 of 200 samples). Environmental contamination was not associated with day of illness, ventilatory mode, aerosol-generating procedures, or viral load. The frequency of environmental contamination was lower in the ICU than in general ward rooms. Eight samples from the common area were positive, though all were negative on cell culture.Conclusion:Environmental contamination in the ICU was lower than in the general wards. The use of mechanical ventilation or high-flow nasal oxygen was not associated with greater surface contamination, supporting their use and safety from an infection control perspective. Transmission risk via environmental surfaces in the ICUs is likely to be low. Nonetheless, infection control practices should be strictly reinforced, and transmission risk via droplet or airborne spread remains.

The complete picture regarding transmission modes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. This review summarises the available evidence on its transmission modes, our preliminary research findings and implications for infection control policy, and outlines future research directions. Environmental contamination has been reported in hospital settings occupied by infected patients, and is higher in the first week of illness. Transmission via environmental surfaces or fomites is likely, but decontamination protocols are effective in minimising this risk. The extent of airborne transmission is also unclear. While several studies have detected SARS-CoV-2 ribonucleic acid in air samples, none has isolated viable virus in culture. Transmission likely lies on a spectrum between droplet and airborne transmission, depending on the patient, disease and environmental factors. Singapore’s current personal protective equipment and isolation protocols are sufficient to manage this risk.

BackgroundMultiple SARS-CoV-2 superspreading events suggest that aerosols play an important role in driving the COVID-19 pandemic. However, the detailed roles of coarse (>5μm) and fine (≤5μm) respiratory aerosols produced when breathing, talking, and singing are not well-understood.MethodsUsing a G-II exhaled breath collector, we measured viral RNA in coarse and fine respiratory aerosols emitted by COVID-19 patients during 30 minutes of breathing, 15 minutes of talking, and 15 minutes of singing.ResultsAmong the 22 study participants, 13 (59%) emitted detectable levels of SARS-CoV-2 RNA in respiratory aerosols, including 3 asymptomatic patients and 1 presymptomatic patient. Viral loads ranged from 63–5,821 N gene copies per expiratory activity per patient. Patients earlier in illness were more likely to emit detectable RNA, and loads differed significantly between breathing, talking, and singing. The largest proportion of SARS-CoV-2 RNA copies was emitted by singing (53%), followed by talking (41%) and breathing (6%). Overall, fine aerosols constituted 85% of the viral load detected in our study. Virus cultures were negative.ConclusionsFine aerosols produced by talking and singing contain more SARS-CoV-2 copies than coarse aerosols and may play a significant role in the transmission of SARS-CoV-2. Exposure to fine aerosols should be mitigated, especially in indoor environments where airborne transmission of SARS-CoV-2 is likely to occur. Isolating viable SARS-CoV-2 from respiratory aerosol samples remains challenging, and whether this can be more easily accomplished for emerging SARS-CoV-2 variants is an important enquiry for future studies.Key PointsWe sampled respiratory aerosols emitted by COVID-19 patients and discovered that fine aerosols (≤5μm) generated during talking and singing contain more SARS-CoV-2 copies than coarse aerosols (>5μm) and may play a significant role in the transmission of SARS-CoV-2.

Background: The complications and sequelae of coronavirus disease 2019 (COVID-19) and their effect on long-term health are unclear, and the trajectory of associated immune dysregulation is poorly understood. Methods: We conducted a prospective longitudinal multicenter cohort study at 4 public hospitals in Singapore. Patients with COVID-19 were monitored for a median of 6 months after recovery from acute infection. Clinical symptoms and radiologic data were collected, along with plasma samples for quantification of immune mediators. The relationship between clinical symptoms and immune cytokine profiles was investigated. Results: Two hundred eighty-eight participants were recruited, and follow-up data were available for 183, 175, and 120 participants at days 30, 90, and 180 postsymptom onset, respectively. Symptoms related to COVID-19 were present in 31 (16.9%), 13 (7.4%), and 14 (11.7%) at days 30, 90, and 180. In a multivariable model, age >65 years, non-Chinese ethnicity, and the severity of acute infection were associated with increased likelihood of persistent symptoms. Recovered COVID-19 patients had elevated levels of proinflammatory interleukin (IL)-17A, stem cell factor, IL-12p70, and IL-1β and pro-angiogenic macrophage inflammatory protein 1β, brain-derived neurotrophic factor, and vascular endothelial growth factor at day 180 compared with healthy controls. Higher levels of monocyte chemoattractant protein-1 and platelet-derived growth factor-BB were detected in patients with persistent symptoms, versus symptom-free patients. Conclusions: Approximately 10% of recovered patients had persistent symptoms 6 months after initial infection. Immune cytokine signatures of the recovered patients reflected ongoing chronic inflammation and angiogenesis. Patients with COVID-19 should be monitored closely for emerging long-term health consequences. Agency for Science, Technology and Research (A*STAR) National Medical Research Council (NMRC) National Research Foundation (NRF) Published version Recruitment of study participants and sample collection was funded by the Singapore National Medical Research Council COVID-19 Research Fund (COVID19RF-001, COVID19RF-060) and A*STAR COVID-19 Research funding (H/20/04/g1/006). The SIgN Immunomonitoring Platform is supported by a BMRC IAF 311006 grant and BMRC transition funds (H16/99/b0/011). The SIgN MAP platform was supported by a grant from the National Research Foundation, Immunomonitoring Service Platform (NRF2017_SISFP09) from the National Research Foundation Singapore.

Highlights • In hospitalized older adults with COVID-19, geriatric syndromes are not uncommon. • Frailty and initial acuity are important predictors of COVID-19 disease severity. • CFS and FI are complementary in predicting disease progression in COVID-19., Introduction Older adults with COVID-19 have disproportionately higher rates of severe disease and mortality. It is unclear whether this is attributable to age or attendant age-associated risk factors. This retrospective cohort study aims to characterize hospitalized older adults and examine if comorbidities, frailty and acuity of clinical presentation exert an age-independent effect on COVID-19 severity. Methods We studied 275 patients admitted to the National Centre of Infectious Disease, Singapore. We measured: 1)Charlson Comorbidity Index(CCI) as burden of comorbidities; 2)Clinical Frailty Scale(CFS) and Frailty Index(FI); and 3)initial acuity. We studied characteristics and outcomes of critical illness, stratified by age groups (50–59,60–69 and ≥70). We conducted hierarchical logistic regression in primary model(N = 262, excluding direct admissions to intensive care unit) and sensitivity analysis(N = 275): age and gender in base model, entering CCI, frailty (CFS or FI) and initial acuity sequentially. Results The ≥70 age group had highest CCI(p

Background:Understanding the extent of aerosol-based transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important for tailoring interventions for control of the coronavirus disease 2019 (COVID-19) pandemic. Multiple studies have reported the detection of SARS-CoV-2 nucleic acid in air samples, but only one study has successfully recovered viable virus, although it is limited by its small sample size.Objective:We aimed to determine the extent of shedding of viable SARS-CoV-2 in respiratory aerosols from COVID-19 patients.Methods:In this observational air sampling study, air samples from airborne-infection isolation rooms (AIIRs) and a community isolation facility (CIF) housing COVID-19 patients were collected using a water vapor condensation method into liquid collection media. Samples were tested for presence of SARS-CoV-2 nucleic acid using quantitative real-time polymerase chain reaction (qRT-PCR), and qRT-PCR-positive samples were tested for viability using viral culture.Results:Samples from 6 (50%) of the 12 sampling cycles in hospital rooms were positive for SARS-CoV-2 RNA, including aerosols ranging from 4 µm in diameter. Of 9 samples from the CIF, 1 was positive via qRT-PCR. Viral RNA concentrations ranged from 179 to 2,738 ORF1ab gene copies per cubic meter of air. Virus cultures were negative after 4 blind passages.Conclusion:Although SARS-CoV-2 is readily captured in aerosols, virus culture remains challenging despite optimized sampling methodologies to preserve virus viability. Further studies on aerosol-based transmission and control of SARS-CoV-2 are needed.

The COVID-19 pandemic has taken over the world at an unprecedented scale. As Infectious Diseases fellows, this has come straight into the heart of our specialty and created a unique impact on our training progress and perspective. Here, we reflect on our early experiences during the first three months of battling COVID-19 in Singapore and glean some lessons for this pandemic and beyond.

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.

Understanding the particle size distribution in the air and patterns of environmental contamination of SARS-CoV-2 is essential for infection prevention policies. We aimed to detect SARS-CoV-2 surface and air contamination and study associated patient-level factors. 245 surface samples were collected from 30 airborne infection isolation rooms of COVID-19 patients, and air sampling was conducted in 3 rooms.Air sampling detected SARS-CoV-2 PCR-positive particles of sizes >4 µm and 1-4 µm in two rooms, which warrants further study of the airborne transmission potential of SARS-CoV-2. 56.7% of rooms had at least one environmental surface contaminated. High touch surface contamination was shown in ten (66.7%) out of 15 patients in the first week of illness, and three (20%) beyond the first week of illness (p = 0.010).

Objectives A wide range of duration of viral RNA shedding in patients infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) has been observed. We aimed to investigate factors associated with prolonged and intermittent viral RNA shedding in a retrospective cohort of symptomatic COVID‐19 patients. Methods Demographic, clinical and laboratory data from hospitalised COVID‐19 patients from a single centre with two consecutive negative respiratory reverse transcription‐polymerase chain reaction (RT‐PCR) results were extracted from electronic medical records. Kaplan–Meier survival curve analysis was used to assess the effect of clinical characteristics on the duration and pattern of shedding. Plasma levels of immune mediators were measured using Luminex multiplex microbead‐based immunoassay. Results There were 201 symptomatic patients included. Median age was 49 years (interquartile range 16–61), and 52.2% were male. Median RNA shedding was 14 days (IQR 9–18). Intermittent shedding was observed in 77 (38.3%). We did not identify any factor associated with prolonged or intermittent viral RNA shedding. Duration of shedding was inversely correlated with plasma levels of T‐cell cytokines IL‐1β and IL‐17A at the initial phase of infection, and patients had lower levels of pro‐inflammatory cytokines during intermittent shedding. Conclusions Less active T‐cell responses at the initial phase of infection were associated with prolonged viral RNA shedding, suggesting that early immune responses are beneficial to control viral load and prevent viral RNA shedding. Intermittent shedding is common and may explain re‐detection of viral RNA in recovered patients., We studied 201 patients with PCR‐confirmed COVID‐19 infection. We found median RNA shedding was 14 days and intermittent RNA shedding was observed in 38.3%. The only associated clinical factor with prolonged RNA shedding was invasive mechanical ventilation. Importantly, we observed in a subset of patients with cytokine analysis, that prolonged RNA shedding was associated with EGF, FGF‐2, GRO‐α and RANTES at the initial phase of infection. Intermittent RNA shedding was associated with lower levels of pro‐inflammatory cytokines.