Trends in Severe Outcomes Among Adult and Pediatric Patients Hospitalized With COVID-19 in the Canadian Nosocomial Infection Surveillance Program, March 2020 to May 2022.

Importance: Trends in COVID-19 severe outcomes have significant implications for the health care system and are key to informing public health measures. However, data summarizing trends in severe outcomes among patients hospitalized with COVID-19 in Canada are not well described. Objective: To describe trends in severe outcomes among patients hospitalized with COVID-19 during the first 2 years of the COVID-19 pandemic. Design, Setting, and Participants: Active prospective surveillance in this cohort study was conducted from March 15, 2020, to May 28, 2022, at a sentinel network of 155 acute care hospitals across Canada. Participants included adult (aged ≥18 years) and pediatric (aged 0-17 years) patients hospitalized with laboratory-confirmed COVID-19 at a Canadian Nosocomial Infection Surveillance Program (CNISP)-participating hospital. Exposures: COVID-19 waves, COVID-19 vaccination status, and age group. Main Outcomes and Measures: The CNISP collected weekly aggregate data on the following severe outcomes: hospitalization, admission to an intensive care unit (ICU), receipt of mechanical ventilation, receipt of extracorporeal membrane oxygenation, and all-cause in-hospital death. Results: Among 1 513 065 admissions, the proportion of adult (n = 51 679) and pediatric (n = 4035) patients hospitalized with laboratory-confirmed COVID-19 was highest in waves 5 and 6 of the pandemic compared with waves 1 to 4 (77.3 vs 24.7 per 1000 patient admissions). Despite this, the proportion of patients with positive test results for COVID-19 who were admitted to an ICU, received mechanical ventilation, received extracorporeal membrane oxygenation, and died were each significantly lower in waves 5 and 6 when compared with waves 1 through 4. Admission to the ICU and in-hospital all-cause death rates were significantly higher among those who were unvaccinated against COVID-19 when compared with those who were fully vaccinated (incidence rate ratio, 4.3 and 3.9, respectively) or fully vaccinated with an additional dose (incidence rate ratio, 12.2 and 15.1, respectively). Conclusions and Relevance: The findings of this cohort study of patients hospitalized with laboratory-confirmed COVID-19 suggest that COVID-19 vaccination is important to reduce the burden on the Canadian health care system as well as severe outcomes associated with COVID-19.

Validation and implementation of group electronic hand hygiene monitoring across twenty-four critical care units.

OBJECTIVES: An accurate estimate of the average number of hand hygiene opportunities per patient hour (HHO rate) is required to implement group electronic hand hygiene monitoring systems (GEHHMSs). We sought to identify predictors of HHOs to validate and implement a GEHHMS across a network of critical care units. DESIGN: Multicenter, observational study (10 hospitals) followed by quality improvement intervention involving 24 critical care units across 12 hospitals in Ontario, Canada. METHODS: Critical care patient beds were randomized to receive 1 hour of continuous direct observation to determine the HHO rate. A Poisson regression model determined unit-level predictors of HHOs. Estimates of average HHO rates across different types of critical care units were derived and used to implement and evaluate use of GEHHMS. RESULTS: During 2,812 hours of observation, we identified 25,417 HHOs. There was significant variability in HHO rate across critical care units. Time of day, day of the week, unit acuity, patient acuity, patient population and use of transmission-based precautions were significantly associated with HHO rate. Using unit-specific estimates of average HHO rate, aggregate HH adherence was 30.0% (1,084,329 of 3,614,908) at baseline with GEHHMS and improved to 38.5% (740,660 of 1,921,656) within 2 months of continuous feedback to units (P < .0001). CONCLUSIONS: Unit-specific estimates based on known predictors of HHO rate enabled broad implementation of GEHHMS. Further longitudinal quality improvement efforts using this system are required to assess the impact of GEHHMS on both HH adherence and clinical outcomes within critically ill patient populations.

Viral dynamics of the SARS-CoV-2 Omicron Variant among household contacts with 2 or 3 COVID-19 vaccine doses.

OBJECTIVES: SARS-CoV-2 shedding has changed as new variants have emerged. It is important to understand the trajectory of PCR positivity due to Omicron in vaccinated populations. METHODS: Double- or triple-vaccinated adult household contacts of individuals with COVID-19 self-collected oral-nasal swabs for 14 days. A hierarchical linear model estimated viral load trajectories and an exploratory logistic regression model assessed for factors associated with viral detection before symptom onset. RESULTS: Forty-one participants developed COVID-19 with 37 (90%) symptomatic. Viral load peaked 3 days after symptom onset at a median concentration of 8.83 log10 copies/milliliter (range 5.95-10.32) and the mean difference between participants with two or three COVID-19 vaccine doses was 0.02 log10 copies/milliliter (95% CI -0.13 to 0.16). PCR positivity began with a range of 4 days prior to 3 days after symptom onset and was positive on the day of symptom onset in 76% (28/37). SARS-CoV-2 detection on the day of symptom onset was less likely among those with 2 vaccine doses (OR 0.13, 95%CI 0.02-0.79). 68% (25/37) of infected participants had detectable SARS-CoV-2 with Ct<30 at 7 days after symptom onset. CONCLUSIONS: Peak viral load and duration of PCR positivity were similar in participants with COVID-19 after two versus three COVID-19 vaccine doses. Onset of viral detection relative to symptom onset was variable.

Trends in Clostridioides difficile infection rates in Canadian hospitals during the coronavirus disease 2019 (COVID-19) pandemic.

The coronavirus disease 2019 (COVID-19) pandemic has placed significant burden on healthcare systems. We compared Clostridioides difficile infection (CDI) epidemiology before and during the pandemic across 71 hospitals participating in the Canadian Nosocomial Infection Surveillance Program. Using an interrupted time series analysis, we showed that CDI rates significantly increased during the COVID-19 pandemic.

Older Age and Frailty are Associated with Higher Mortality but Lower ICU Admission with COVID-19.

Background: We report characteristics and outcomes of adults admitted to Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network hospitals with COVID-19 in 2020. Methods: Patients with laboratory-confirmed COVID-19 admitted to 11 sites in Ontario, Quebec, Alberta, and Nova Scotia up to December 31, 2020 were enrolled in this prospective observational cohort study. Measures included age, sex, demographics, housing, exposures, Clinical Frailty Scale, comorbidities; in addition, length of stay, intensive care unit (ICU) admission, mechanical ventilation, and survival were assessed. Descriptive analyses and multivariable logistic regressions were conducted. Results: Among 2,011 patients, mean age was 71.0 (range 19-105) years. 29.7% were admitted from assisted living or long-term care facilities. The full spectrum of frailty was represented in both younger and older age groups. 81.8% had at least one underlying comorbidity and 27.2% had obesity. Mortality was 14.3% without ICU admission, and 24.6% for those admitted to ICU. Older age and frailty were independent predictors of lower ICU use and higher mortality; accounting for frailty, obesity was not an independent predictor of mortality, and associations of comorbidities with mortality were weakened. Conclusions: Frailty is a critical clinical factor in predicting outcomes of COVID-19, which should be considered in research and clinical settings.

Surface and Air Contamination With Severe Acute Respiratory Syndrome Coronavirus 2 From Hospitalized Coronavirus Disease 2019 Patients in Toronto, Canada, March-May 2020.

BACKGROUND: We determined the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in air and on surfaces in rooms of patients hospitalized with coronavirus disease 2019 (COVID-19) and investigated patient characteristics associated with SARS-CoV-2 environmental contamination. METHODS: Nasopharyngeal swabs, surface, and air samples were collected from the rooms of 78 inpatients with COVID-19 at 6 acute care hospitals in Toronto from March to May 2020. Samples were tested for SARS-CoV-2 ribonucleic acid (RNA), cultured to determine potential infectivity, and whole viral genomes were sequenced. Association between patient factors and detection of SARS-CoV-2 RNA in surface samples were investigated. RESULTS: Severe acute respiratory syndrome coronavirus 2 RNA was detected from surfaces (125 of 474 samples; 42 of 78 patients) and air (3 of 146 samples; 3 of 45 patients); 17% (6 of 36) of surface samples from 3 patients yielded viable virus. Viral sequences from nasopharyngeal and surface samples clustered by patient. Multivariable analysis indicated hypoxia at admission, polymerase chain reaction-positive nasopharyngeal swab (cycle threshold of ≤30) on or after surface sampling date, higher Charlson comorbidity score, and shorter time from onset of illness to sampling date were significantly associated with detection of SARS-CoV-2 RNA in surface samples. CONCLUSIONS: The infrequent recovery of infectious SARS-CoV-2 virus from the environment suggests that the risk to healthcare workers from air and near-patient surfaces in acute care hospital wards is likely limited.

Impact of COVID-19 on hospital hand hygiene performance: a multicentre observational study using group electronic monitoring.

BACKGROUND: Reliable reports on hand hygiene performance throughout the COVID-19 pandemic are lacking as most hospitals continue to rely on direct observation to measure this quality indicator. Using group electronic hand hygiene monitoring, we sought to assess the impact of COVID-19 on adherence to hand hygiene. METHODS: Across 12 Ontario hospitals (5 university and 7 community teaching hospitals), a group electronic hand hygiene monitoring system was installed before the pandemic to provide continuous measurement of hand hygiene adherence across 978 ward and 367 critical care beds. We performed an interrupted time-series study of institutional hand hygiene adherence in association with a COVID-19 inpatient census and the Ontario daily count of COVID-19 cases during a baseline period (Nov. 1, 2019, to Feb. 29, 2020), the pre-peak period of the first wave of the pandemic (Mar. 1 to Apr. 24, 2020), and the post-peak period of the first wave (Apr. 25 to July 5, 2020). We used a Poisson regression model to assess the association between the hospital COVID-19 census and institutional hand hygiene adherence while adjusting for the correlation within inpatient units. RESULTS: At baseline, the rate of hand hygiene adherence was 46.0% (6 325 401 of 13 750 968 opportunities) and this improved beginning in March 2020 to a daily peak of 79.3% (66 640 of 84 026 opportunities) on Mar. 30, 2020. Each patient admitted with COVID-19 was associated with improved hand hygiene adherence (incidence rate ratio [IRR] 1.0621, 95% confidence interval [CI] 1.0619-1.0623). Increasing Ontario daily case count was similarly associated with improved hand hygiene (IRR 1.0026, 95% CI 1.0021-1.0032). After peak COVID-19 community and inpatient numbers, hand hygiene adherence declined and returned to baseline. INTERPRETATION: The first wave of the COVID-19 pandemic was associated with significant improvement in hand hygiene adherence, measured using a group electronic monitoring system. Future research should seek to determine whether strategies that focus on health care worker perception of personal risk can achieve sustainable improvements in hand hygiene performance.

Detection of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in outpatients: A multicenter comparison of self-collected saline gargle, oral swab, and combined oral-anterior nasal swab to a provider collected nasopharyngeal swab.

BACKGROUND: Widespread testing for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) is necessary to curb the spread of coronavirus disease 2019 (COVID-19), but testing is undermined when the only option is a nasopharyngeal swab. Self-collected swab techniques can overcome many of the disadvantages of a nasopharyngeal swab, but they require evaluation. METHODS: Three self-collected non-nasopharyngeal swab techniques (saline gargle, oral swab and combined oral-anterior nasal swab) were compared to a nasopharyngeal swab for SARS-CoV-2 detection at multiple COVID-19 assessment centers in Toronto, Canada. The performance characteristics of each test were assessed. RESULTS: The adjusted sensitivity of the saline gargle was 0.90 (95% CI 0.86-0.94), the oral swab was 0.82 (95% CI, 0.72-0.89) and the combined oral-anterior nasal swab was 0.87 (95% CI, 0.77-0.93) compared to a nasopharyngeal swab, which demonstrated a sensitivity of ˜90% when all positive tests were the reference standard. The median cycle threshold values for the SARS-CoV-2 E-gene for concordant and discordant saline gargle specimens were 17 and 31 (P < .001), for the oral swabs these values were 17 and 28 (P < .001), and for oral-anterior nasal swabs these values were 18 and 31 (P = .007). CONCLUSIONS: Self-collected saline gargle and an oral-anterior nasal swab have a similar sensitivity to a nasopharyngeal swab for the detection of SARS-CoV-2. These alternative collection techniques are cheap and can eliminate barriers to testing, particularly in underserved populations.

SARS-CoV-2 antibodies in Ontario health care workers during and after the first wave of the pandemic: a cohort study.

BACKGROUND: Health care workers have a critical role in the pandemic response to COVID-19 and may be at increased risk of infection. The objective of this study was to assess the seroprevalence of SARS-CoV-2 immunoglobulin G (IgG) antibodies among health care workers during and after the first wave of the pandemic. METHODS: We conducted a prospective multicentre cohort study involving health care workers in Ontario, Canada, to detect IgG antibodies against SARS-CoV-2. Blood samples and self-reported questionnaires were obtained at enrolment, at 6 weeks and at 12 weeks. A community hospital, tertiary care pediatric hospital and a combined adult-pediatric academic health centre enrolled participants from Apr. 1 to Nov. 13, 2020. Predictors of seropositivity were evaluated using a multivariable logistic regression, adjusted for clustering by hospital site. RESULTS: Among the 1062 health care workers participating, the median age was 40 years, and 834 (78.5%) were female. Overall, 57 (5.4%) were seropositive at any time point (2.5% when participants with prior infection confirmed by polymerase chain reaction testing were excluded). Seroprevalence was higher among those who had a known unprotected exposure to a patient with COVID-19 (p < 0.001) and those who had been contacted by public health because of a nonhospital exposure (p = 0.003). Providing direct care to patients with COVID-19 or working on a unit with a COVID-19 outbreak was not associated with higher seroprevalence. In multivariable logistic regression, presence of symptomatic contacts in the household was the strongest predictor of seropositivity (adjusted odds ratio 7.15, 95% confidence interval 5.42-9.41). INTERPRETATION: Health care workers exposed to household risk factors were more likely to be seropositive than those not exposed, highlighting the need to emphasize the importance of public health measures both inside and outside of the hospital.

One swab, two tests: Validation of dual SARS-CoV-2 testing on the Abbott ID NOW™.

BACKGROUND: Point-of-care tests (POCT) are promising tools to detect SARS-CoV-2 in specific settings. Initial reports suggest the ID NOW™ COVID-19 assay (Abbott Diagnostics Inc, USA) is less sensitive than standard real-time reverse transcription polymerase chain reaction (rRT-PCR) assays. This has raised concern over false negatives in SARS-CoV-2 POCT. OBJECTIVES: We compared the performance of the ID NOW™ COVID-19 assay to our in-house rRT-PCR assay to assess whether dry swabs used in ID NOW™ testing could be stored in transport media and be re-tested by rRT-PCR for redundancy and to provide material for further investigation. METHODS: Paired respiratory swabs collected from patients at three acute care hospitals were used. One swab in transport media (McMaster Molecular Media (MMM)) was tested for SARS-CoV-2 by a laboratory-developed two-target rRT-PCR assay. The second was stored dry in a sterile container and tested by the ID NOW™ COVID-19 assay. Following ID NOW™ testing, dry swabs were stored in MMM for up to 48 h and re-tested by rRT-PCR. Serially diluted SARS-CoV-2 particles were used to assess the impact of heat inactivation and storage time. RESULTS: Respiratory swabs (n = 343) from 179 individuals were included. Using rRT-PCR results as the comparator, the ID NOW™ COVID-19 assay had positive (PPA) and negative (NPA) percent agreements of 87.0% (95% CI:0.74-0.94) and 99.7% (95% CI:0.98-0.99). Re-tested swabs placed in MMM following ID NOW testing had PPA and NPA of 88.8% (95% CI:0.76-0.95) and 99.7% (95% CI:0.98-0.99), respectively. CONCLUSIONS: Storing spent dry swabs in transport media for redundancy rRT-PCR testing is a potential approach to address possible false negatives with the ID NOW™ COVID-19 assay.

SARS-CoV-2 Testing for Asymptomatic Patients with Cancer Prior and during Treatment: A Single Centre Experience.

Patients with cancer are more vulnerable to severe COVID-19. As a result, routine SARS-CoV-2 testing of asymptomatic patients with cancer is recommended prior to treatment. However, there is limited evidence of its clinical usefulness. The objective of this study is to evaluate the value of routine testing of asymptomatic patients with cancer. Asymptomatic patients with cancer attending Odette Cancer Centre (Toronto, ON, Canada) were tested for SARS-CoV-2 prior to and during treatment cycles. Results were compared to positivity rates of SARS-CoV-2 locally and provincially. All 890 asymptomatic patients tested negative. Positivity rates in the province were 1.5%, in hospital were 1.0%, and among OCC's symptomatic cancer patients were 0% over the study period. Given our findings and the low SARS-CoV-2 community positivity rates, we recommend a dynamic testing model of asymptomatic patients that triggers testing during increasing community positivity rates of SARS-CoV-2.

Implementation and Evaluation of an IPAC SWAT Team Mobilized to Long-Term Care and Retirement Homes During the COVID-19 Pandemic: A Pragmatic Health System Innovation.

Long-term care facilities (LTCFs), retirement homes (RHs), and other congregate care settings in Canada and worldwide have experienced significant COVID-19 outbreaks. As a health system response, our acute care hospital in Toronto, Ontario, Canada, developed and mobilized an onsite Infection Prevention and Control (IPAC) SWAT team (IPAC-SWAT) to regional settings on outbreak and implemented a strategy of support through education, training, and engagement. Between April 28, 2020, and June 30, 2020, IPAC-SWAT assessed 7 LTCFs and 10 RHs for IPAC preparedness and actively managed 10 of 13 COVID-19 outbreaks (LTCF n=5; RH n=5). IPAC-SWAT strategies were multi-interventional and intended to mitigate further viral transmission or prevent outbreaks. Dedicated training of local "IPAC champions" was facilitated at 7 sites (LTCF = 5; RH = 2) using a "train-the-trainer" approach to promote local knowledge, autonomy, and site-led audits and feedback.

Questionnaire-based vs universal PCR testing for SARS-CoV-2 in women admitted for delivery.

BACKGROUND: It has been suggested that women admitted for delivery should have universal PCR testing for SARS-CoV-2. Yet, the considerable difference in the incidence of COVID-19 between different geographic regions may affect screening strategies. Therefore, we aimed to compare questionnaire-based testing versus universal PCR testing for SARS-CoV-2 in women admitted for delivery. METHODS: A prospective cohort study of women admitted for delivery at a single center during a four-week period (April 22-May 25, 2020). All women completed a questionnaire about COVID-19 signs, symptoms, or risk factors, and a nasopharyngeal swab for PCR for SARS-CoV-2. Women who were flagged as suspected COVID-19 by the questionnaire (questionnaire-positive) were compared with women who were not flagged by the questionnaire (questionnaire-negative). RESULTS: Overall, 446 women were eligible for analysis, of which 54 (12.1%) were questionnaire-positive. PCR swab detected SARS-CoV-2 in four (0.9%) women: 3 of 392 (0.8%) in the questionnaire-negative group, and 1 of 54 (1.9%) in the questionnaire-positive group (P = .43), yielding a number needed to screen of 92 (95% CI 62-177). In 96% of the cases, the PCR results were obtained only in the postpartum period. No positive PCR results were obtained from neonatal testing for SARS-CoV-2. The sensitivity of the questionnaire was 75.0%, and the negative predictive value was 99.7%. CONCLUSIONS: Although the rate of positive PCR results was not significantly different between the groups, the number needed to screen is considerably high. The use of questionnaire-based PCR testing in areas with low incidence of COVID-19 allows for a reasonable allocation of resources and is easy to implement.

Detection of SARS-CoV-2 from Saliva as Compared to Nasopharyngeal Swabs in Outpatients.

Widely available and easily accessible testing for COVID-19 is a cornerstone of pandemic containment strategies. Nasopharyngeal swabs (NPS) are the currently accepted standard for sample collection but are limited by their need for collection devices and sampling by trained healthcare professionals. The aim of this study was to compare the performance of saliva to NPS in an outpatient setting. This was a prospective study conducted at three centers, which compared the performance of saliva and NPS samples collected at the time of assessment center visit. Samples were tested by real-time reverse transcription polymerase chain reaction and sensitivity and overall agreement determined between saliva and NPS. Clinical data was abstracted by chart review for select study participants. Of the 432 paired samples, 46 were positive for SARS-CoV-2, with seven discordant observed between the two sample types (four individuals testing positive only by NPS and three by saliva only). The observed agreement was 98.4% (kappa coefficient 0.91) and a composite reference standard demonstrated sensitivity of 0.91 and 0.93 for saliva and NPS samples, respectively. On average, the Ct values obtained from saliva as compared to NPS were higher by 2.76. This study demonstrates that saliva performs comparably to NPS for the detection of SARS-CoV-2. Saliva was simple to collect, did not require transport media, and could be tested with equipment readily available at most laboratories. The use of saliva as an acceptable alternative to NPS could support the use of widespread surveillance testing for SARS-CoV-2.