Cohort profile: SARS-CoV-2/COVID-19 hospitalised patients in Switzerland.

BACKGROUND: SARS-CoV-2/COVID-19, which emerged in China in late 2019, rapidly spread across the world with several million victims in 213 countries. Switzerland was severely hit by the virus, with 43,000 confirmed cases as of 1 September 2020. AIM: In cooperation with the Federal Office of Public Health, we set up a surveillance database in February 2020 to monitor hospitalised patients with COVID-19, in addition to their mandatory reporting system. METHODS: Patients hospitalised for more than 24 hours with a positive polymerase chain-reaction test, from 20 Swiss hospitals, are included. Data were collected in a customised case report form based on World Health Organisation recommendations and adapted to local needs. Nosocomial infections were defined as infections for which the onset of symptoms was more than 5 days after the patient’s admission date. RESULTS: As of 1 September 2020, 3645 patients were included. Most patients were male (2168, 59.5%), and aged between 50 and 89 years (2778, 76.2%), with a median age of 68 (interquartile range 54–79). Community infections dominated with 3249 (89.0%) reports. Comorbidities were frequently reported, with hypertension (1481, 61.7%), cardiovascular diseases (948, 39.5%) and diabetes (660, 27.5%) being the most frequent in adults; respiratory diseases and asthma (4, 21.1%), haematological and oncological diseases (3, 15.8%) were the most frequent in children. Complications occurred in 2679 (73.4%) episodes, mostly respiratory diseases (2470, 93.2% in adults; 16, 55.2% in children), and renal (681, 25.7%) and cardiac (631, 23.8%) complications for adults. The second and third most frequent complications in children affected the digestive system and the liver (7, 24.1%). A targeted treatment was given in 1299 (35.6%) episodes, mostly with hydroxychloroquine (989, 76.1%). Intensive care units stays were reported in 578 (15.8%) episodes. A total of 527 (14.5%) deaths were registered, all among adults. CONCLUSION: The surveillance system has been successfully initiated and provides a robust set of data for Switzerland by including about 80% (compared with official statistics) of SARS-CoV-2/COVID-19 hospitalised patients, with similar age and comorbidity distributions. It adds detailed information on the epidemiology, risk factors and clinical course of these cases and, therefore, is a valuable addition to the existing mandatory reporting.

Evolution of COVID-19 mortality over time: results from the Swiss hospital surveillance system (CH-SUR).

BACKGROUND: When the periods of time during and after the first wave of the ongoing SARS-CoV-2/COVID-19 pandemic in Europe are compared, the associated COVID-19 mortality seems to have decreased substantially. Various factors could explain this trend, including changes in demographic characteristics of infected persons and the improvement of case management. To date, no study has been performed to investigate the evolution of COVID-19 in-hospital mortality in Switzerland, while also accounting for risk factors. METHODS: We investigated the trends in COVID-19-related mortality (in-hospital and in-intermediate/intensive-care) over time in Switzerland, from February 2020 to June 2021, comparing in particular the first and the second wave. We used data from the COVID-19 Hospital-based Surveillance (CH-SUR) database. We performed survival analyses adjusting for well-known risk factors of COVID-19 mortality (age, sex and comorbidities) and accounting for competing risk. RESULTS: Our analysis included 16,984 patients recorded in CH-SUR, with 2201 reported deaths due to COVID-19 (13.0%). We found that overall in-hospital mortality was lower during the second wave of COVID-19 than in the first wave (hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.63- 0.78; p <0.001), a decrease apparently not explained by changes in demographic characteristics of patients. In contrast, mortality in intermediate and intensive care significantly increased in the second wave compared with the first wave (HR 1.25, 95% CI 1.05-1.49; p = 0.029), with significant changes in the course of hospitalisation between the first and the second wave. CONCLUSION: We found that, in Switzerland, COVID-19 mortality decreased among hospitalised persons, whereas it increased among patients admitted to intermediate or intensive care, when comparing the second wave to the first wave. We put our findings in perspective with changes over time in case management, treatment strategy, hospital burden and non-pharmaceutical interventions. Further analyses of the potential effect of virus variants and of vaccination on mortality would be crucial to have a complete overview of COVID-19 mortality trends throughout the different phases of the pandemic.

Challenges Related to Surgical Site Infection Prevention-Results after Standardized Bundle Implementation.

AIM: The aim of this study was to assess the implementation of an intraoperative standardized surgical site infection (SSI) prevention bundle. METHODS: The multimodal, evidence-based care bundle included nine intraoperative items (antibiotic type, timing, and re-dosing; disinfection; induction temperature control > 36.5°; glove change; intra-cavity lavage; wound protection; and closure strategy). The bundle was applied to all consecutive patients undergoing colonic resections. The primary outcome, SSI, was independently assessed by the National Infection Surveillance Committee for up to 30 postoperative days. A historical, institutional pre-implementation control group (2012-2017) with an identical methodology was used for comparison. FINDINGS: In total, 1516 patients were included, of which 1256 (82.8%) were in the control group and 260 (17.2%) were in the post-implementation group. After 2:1 propensity score matching, the groups were similar for all items (p > 0.05). Overall compliance with the care bundle was 77% (IQR 77-88). The lowest compliance rates were observed for temperature control (53% overall), intra-cavity lavage (64% overall), and wound protection and closure (68% and 63% in the SSI group, respectively). Surgical site infections were reported in 58 patients (22.2%) vs. 21.4% in the control group (p = 0.79). Infection rates were comparable throughout the Centers for Disease Control and Prevention (CDC) categories: superficial, 12 patients (4.5%) vs. 4.2%, p = 0.82; deep incisional, 10 patients (3.7%) vs. 5.1%, p = 0.34; organ space, 36 (14%) vs. 12.4%, p = 0.48. After propensity score matching, rates remained comparable throughout all comparisons (all p > 0.05). CONCLUSIONS: The implementation of an intraoperative standardized care bundle had no impact on SSI rates. This may be explained by insufficient compliance with the individual measures.

COVID-19 Outbreak at a Geriatric Rehabilitation Facility: The Silent Threat of Asymptomatic Patients with High Viral Loads.

Data about outbreaks of nosocomial COVID-19 disease within geriatric rehabilitation facilities are scarce. In this retrospective case series analysis, we describe such an outbreak, determine the proportion of a-/presymptomatic patients, the median time before symptom onset among presymptomatic patients and investigate whether the viral load differs between patients with and without symptoms. Typical and atypical symptoms were retrieved from the electronic medical records of patients who tested positive for COVID-19 disease during their stay at a 95-bed geriatric rehabilitation facility. The viral load at the time of diagnosis was estimated on cycle threshold values of the rRT-PCR test. Overall, 34 patients (median age, 87 years; range, 66-98; 67% female) tested positive for SARS-CoV-2. During the same period, 19 health care workers were also diagnosed with COVID-19. Among the 27 patients who provided consent, 20 (74%) were symptomatic at the time of testing. Among the remaining seven patients, six developed symptoms after a median of 2 days. A viral load > 106 copies/mL was observed in 20 out of the 27 patients, including five out of the seven initially asymptomatic patients. The rapid transmission of SARS-CoV-2 and the prevalence of initially asymptomatic patients with high viral loads support an extended screening strategy at such facilities.

Risk factors for severe outcomes for COVID-19 patients hospitalised in Switzerland during the first pandemic wave, February to August 2020: prospective observational cohort study.

BACKGROUND: As clinical signs of COVID-19 differ widely among individuals, from mild to severe, the definition of risk groups has important consequences for recommendations to the public, control measures and patient management, and needs to be reviewed regularly. AIM: The aim of this study was to explore risk factors for in-hospital mortality and intensive care unit (ICU) admission for hospitalised COVID-19 patients during the first epidemic wave in Switzerland, as an example of a country that coped well during the first wave of the pandemic. METHODS: This study included all (n = 3590) adult polymerase chain reaction (PCR)-confirmed hospitalised patients in 17 hospitals from the hospital-based surveillance of COVID-19 (CH-Sur) by 1 September 2020. We calculated univariable and multivariable (adjusted) (1) proportional hazards (Fine and Gray) survival regression models and (2) logistic regression models for in-hospital mortality and admission to ICU, to evaluate the most common comorbidities as potential risk factors. RESULTS AND DISCUSSION: We found that old age was the strongest factor for in-hospital mortality after having adjusted for gender and the considered comorbidities (hazard ratio [HR] 2.46, 95% confidence interval [CI] 2.33−2.59 and HR 5.6 95% CI 5.23−6 for ages 65 and 80 years, respectively). In addition, male gender remained an important risk factor in the multivariable models (HR 1.47, 95% CI 1.41−1.53). Of all comorbidities, renal disease, oncological pathologies, chronic respiratory disease, cardiovascular disease (but not hypertension) and dementia were also risk factors for in-hospital mortality. With respect to ICU admission risk, the pattern was different, as patients with higher chances of survival might have been admitted more often to ICU. Male gender (OR 1.91, 95% CI 1.58−2.31), hypertension (OR  1.3, 95% CI 1.07−1.59) and age 55–79 years (OR 1.15, 95% CI 1.06−1.26) are risk factors for ICU admission. Patients aged 80+ years, as well as patients with dementia or with liver disease were admitted less often to ICU. CONCLUSION: We conclude that increasing age is the most important risk factor for in-hospital mortality of hospitalised COVID-19 patients in Switzerland, along with male gender and followed by the presence of comorbidities such as renal diseases, chronic respiratory or cardiovascular disease, oncological malignancies and dementia. Male gender, hypertension and age between 55 and 79 years are, however, risk factors for ICU admission. Mortality and ICU admission need to be considered as separate outcomes when investigating risk factors for pandemic control measures and for hospital resources planning.

SARS-CoV-2 seroprevalence in healthcare workers of a Swiss tertiary care centre at the end of the first wave: a cross-sectional study.

OBJECTIVE: To assess the SARS-CoV-2 transmission in healthcare workers (HCWs) using seroprevalence as a surrogate marker of infection in our tertiary care centre according to exposure. DESIGN: Seroprevalence cross-sectional study. SETTING: Single centre at the end of the first COVID-19 wave in Lausanne, Switzerland. PARTICIPANTS: 1874 of 4074 responders randomly selected (46% response rate), stratified by work category among the 13 474 (13.9%) HCWs. MAIN OUTCOME MEASURES: Evaluation of SARS-CoV-2 serostatus paired with a questionnaire of SARS-CoV-2 acquisition risk factors internal and external to the workplace. RESULTS: The overall SARS-CoV-2 seroprevalence rate among HCWs was 10.0% (95% CI 8.7% to 11.5%). HCWs with daily patient contact did not experience increased rates of seropositivity relative to those without (10.3% vs 9.6%, respectively, p=0.64). HCWs with direct contact with patients with COVID-19 or working in COVID-19 units did not experience increased seropositivity rates relative to their counterparts (10.4% vs 9.8%, p=0.69 and 10.6% vs 9.9%, p=0.69, respectively). However, specific locations of contact with patients irrespective of COVID-19 status-in patient rooms or reception areas-did correlate with increased rates of seropositivity (11.9% vs 7.5%, p=0.019 and 14.3% vs 9.2%, p=0.025, respectively). In contrast, HCWs with a suspected or proven SARS-CoV-2-infected household contact had significantly higher seropositivity rates than those without such contacts (19.0% vs 8.7%, p<0.001 and 42.1% vs 9.4%, p<0.001, respectively). Finally, consistent use of a mask on public transportation correlated with decreased seroprevalence (5.3% for mask users vs 11.2% for intermittent or no mask use, p=0.030). CONCLUSIONS: The overall seroprevalence was 10% without significant differences in seroprevalence between HCWs exposed to patients with COVID-19 and HCWs not exposed. This suggests that, once fully in place, protective measures limited SARS-CoV-2 occupational acquisition within the hospital environment. SARS-CoV-2 seroconversion among HCWs was associated primarily with community risk factors, particularly household transmission.

Epidemiology, risk factors and clinical course of SARS-CoV-2 infected patients in a Swiss university hospital: An observational retrospective study.

BACKGROUND: This study aims to describe the epidemiology of COVID-19 patients in a Swiss university hospital. METHODS: This retrospective observational study included all adult patients hospitalized with a laboratory confirmed SARS-CoV-2 infection from March 1 to March 25, 2020. We extracted data from electronic health records. The primary outcome was the need to mechanical ventilation at day 14. We used multivariate logistic regression to identify risk factors for mechanical ventilation. Follow-up was of at least 14 days. RESULTS: 145 patients were included in the multivariate model, of whom 36 (24.8%) needed mechanical ventilation at 14 days. The median time from symptoms onset to mechanical ventilation was 9·5 days (IQR 7.00, 12.75). Multivariable regression showed increased odds of mechanical ventilation with age (OR 1.09 per year, 95% CI 1.03-1.16, p = 0.002), in males (OR 6.99, 95% CI 1.68-29.03, p = 0.007), in patients who presented with a qSOFA score ≥2 (OR 7.24, 95% CI 1.64-32.03, p = 0.009), with bilateral infiltrate (OR 18.92, 3.94-98.23, p<0.001) or with a CRP of 40 mg/l or greater (OR 5.44, 1.18-25.25; p = 0.030) on admission. Patients with more than seven days of symptoms on admission had decreased odds of mechanical ventilation (0.087, 95% CI 0.02-0.38, p = 0.001). CONCLUSIONS: This study gives some insight in the epidemiology and clinical course of patients admitted in a European tertiary hospital with SARS-CoV-2 infection. Age, male sex, high qSOFA score, CRP of 40 mg/l or greater and a bilateral radiological infiltrate could help clinicians identify patients at high risk for mechanical ventilation.