Swiss COVID-19 hospital surveillance: an in-depth analysis of the factors associated with hospital readmission dynamics in community-acquired COVID-19 cases.

BACKGROUND: The COVID-19 pandemic has placed unprecedented pressure on hospitals worldwide. In such a context of tension in healthcare systems, efficiently allocating hospital resources is a crucial aspect of crisis management. The aim of this study was to describe the clinical characteristics of readmitted patients and to determine risk factors for hospital readmission using data from the Swiss COVID-19 Hospital-Based Surveillance system (CH-SUR). METHODS: We investigated hospital readmissions within 60 days after discharge of patients from the CH-SUR surveillance system with a first hospitalisation between 1 December 2020 and 1 December 2021. Only community-acquired cases were considered. We compared the baseline characteristics of readmitted and non-readmitted patients. We performed univariable and multivariable logistic regression analyses to investigate the risk factors for hospital readmission. FINDINGS: Of the 8039 eligible patients, 239 (3.0%, 95% confidence interval [CI] 2.6-3.3%) were readmitted to hospital within 60 days of discharge, with no significant variations observed over the study period; 80% of all readmissions occurred within 10 days of discharge of the index hospital stay. Based on our multivariable logistic regression models, factors increasing the odds of hospital readmission were age ≥65 years (odds ratio [OR] 1.63, 95% CI 1.24-2.15), male sex (OR 1.47, 95% CI 1.12-1.93), being discharged to home after first hospitalisation (OR 1.77, 95% CI 1.19-2.62), having oncological pathology (OR 1.82, 95% CI 1.27-2.61) and being immunosuppressed (OR 2.34, 95% CI 1.67-3.29). INTERPRETATIONS: Age, sex, cardiovascular diseases, oncological pathologies and immunosuppression were the main risk factors identified for hospital readmission.

Colonization with resistant bacteria in hospital employees: an epidemiological surveillance and typing study.

The objective of this study was to determine the prevalence, molecular epidemiology, and risk factors for gut colonization with extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-E), carbapenemase-producing Enterobacterales (CPE), and vancomycin-resistant enterococci (VRE) in healthcare workers (HCWs). In September/October 2022, we performed a cross-sectional study among HCW from 14 institutions in Northeastern Switzerland. HCWs reported risk factors for antimicrobial resistance (covering the last 12-24 months) and provided rectal swabs. Swabs were screened for ESBL-E, CPE, and VRE; whole-genome sequencing (WGS) was performed to assess the genetic relatedness. Logistic regression was used to identify occupational and non-occupational risk factors. Among approximately 22,500 employees, 1,209 participated (median age 46 years, 82% female). Prevalences of ESBL-E (n = 65) and CPE (n = 1) were 5.4% [95% confidence interval (CI) 4.2-6.8] and 0.1% (95% CI 0.0-0.5), respectively; no VREs were detected. In the multivariable analysis, non-European ethnicity [adjusted odds ratio (aOR) 7.0, 95% CI 1.4-27.3], travel to high-risk countries (aOR 4.9, 95% CI 2.5-9.3), systemic antibiotics (aOR 2.1, 95% CI 1.1-3.7), antibiotic eye drops (aOR 4.7, 95% CI 1.7-11.9), and monthly sushi consumption (aOR 2.4, 95% CI 1.4-4.3) were positively associated with ESBL-E colonization, whereas alcohol consumption (aOR 0.5 per glass/week, 95% CI 0.3-0.9) was negatively associated with ESBL-E colonization. Occupational factors showed no association. Among ESBL-Escherichia coli, ST131 (15 of 61, 25%) and blaCTX-M-15 (37/61; 61%) were most common; one isolate co-harbored blaOXA-244. WGS data did not show relevant clustering. Occupational exposure is not associated with ESBL-E colonization in HCW. Given the potential public health and antibiotic stewardship implications, the role of sushi consumption and antibiotic eye drops as risk factors should be further elucidated.

SARS-CoV-2 Vaccination is Not Associated With Involuntary Childlessness in Female Healthcare Workers: A Multicenter Cohort Study.

BACKGROUND: There is debate about the causes of the recent birth rate decline in high-income countries worldwide. During the pandemic, concern about the effects on reproductive health has caused vaccine hesitancy. We investigated the association of SARS-CoV-2 vaccination and infection with involuntary childlessness. METHODS: Females in fertility age within a prospective multicenter cohort of healthcare workers (HCW) were followed since August 2020. Data on baseline health, SARS-CoV-2-infection, and vaccination were obtained and regularly updated, in which serum samples were collected repetitively and screened for anti-nucleocapsid and anti-spike antibodies. In October 2023, participants indicated the presence of involuntary childlessness with onset during the pandemic, whereas those indicating an onset before the pandemic were excluded. The association of involuntary childlessness and SARS-CoV-2-vaccination and infection was investigated using univariable and multivariable analysis. Sensitivity analysis was performed to compare those reporting involuntary childlessness with those birthing a child since 2020. RESULTS: Of 798 participants, 26 (3.2%) reported involuntary childlessness starting since the pandemic. Of the involuntary childless women, 73.1% (19/26) were vaccinated compared to 86.0% (664/772) without involuntary childlessness (p = 0.73). SARS-CoV-2 infection was reported by 76.9% (20/26) compared to 72.4% (559/772) of controls (p = 0.64). Neither SARS-CoV-2 vaccination (aOR 0.91 per dose, 95%CI 0.67-1.26) nor infection (aOR per infection 1.05, 95%CI 0.62-1.71) was associated with involuntary childlessness. Sensitivity analysis confirmed these results. CONCLUSIONS: Among female HCW of fertility age, 3.2% indicated involuntary childlessness, which is comparable to pre-pandemic data. No association between involuntary childlessness and SARS-CoV-2 vaccination or infection was found.

Association of institutional masking policies with healthcare-associated SARS-CoV-2 infections in Swiss acute care hospitals during the BA.4/5 wave (CH-SUR study): a retrospective observational study.

BACKGROUND: In the initial phase of the SARS-CoV-2 pandemic, masking has been widely accepted in healthcare institutions to mitigate the risk of healthcare-associated infection. Evidence, however, is still scant and the role of masks in preventing healthcare-associated SARS-CoV-2 acquisition remains unclear.We investigated the association of variation in institutional mask policies with healthcare-associated SARS-CoV-2 infections in acute care hospitals in Switzerland during the BA.4/5 2022 wave. METHODS: SARS-CoV-2 infections in hospitalized patients between June 1 and September 5, 2022, were obtained from the "Hospital-based surveillance of COVID-19 in Switzerland"-database and classified as healthcare- or community-associated based on time of disease onset. Institutions provided information regarding institutional masking policies for healthcare workers and other prevention policies. The percentage of healthcare-associated SARS-CoV-2 infections was calculated per institution and per type of mask policy. The association of healthcare-associated SARS-CoV-2 infections with mask policies was tested using a negative binominal mixed-effect model. RESULTS: We included 2'980 SARS-CoV-2 infections from 13 institutions, 444 (15%) were classified as healthcare-associated. Between June 20 and June 30, 2022, six (46%) institutions switched to a more stringent mask policy. The percentage of healthcare-associated infections subsequently declined in institutions with policy switch but not in the others. In particular, the switch from situative masking (standard precautions) to general masking of HCW in contact with patients was followed by a strong reduction of healthcare-associated infections (rate ratio 0.39, 95% CI 0.30-0.49). In contrast, when compared across hospitals, the percentage of health-care associated infections was not related to mask policies. CONCLUSIONS: Our findings suggest switching to a more stringent mask policy may be beneficial during increases of healthcare-associated SARS-CoV-2 infections at an institutional level.

SARS-CoV-2 immunity and reasons for non-vaccination among healthcare workers from eastern and northern Switzerland: results from a nested multicentre cross-sectional study.

AIMS OF THE STUDY: We aimed to assess the extent of SARS-CoV-2 humoral immunity elicited by previous infections and/or vaccination among healthcare workers, and to identify reasons why healthcare workers decided against vaccination. METHODS: This nested cross-sectional study included volunteer healthcare workers from 14 healthcare institutions in German-speaking Switzerland. In January 2021, SARS-CoV-2 vaccines were available for healthcare workers. In May and June 2022, participants answered electronic questionnaires regarding baseline characteristics including SARS-CoV-2 vaccination status (with one or more vaccine doses defined as vaccinated) and previous SARS-CoV-2 infections. Unvaccinated participants indicated their reasons for non-vaccination. Participants underwent testing for SARS-CoV-2 anti-spike (anti-S) and anti-nucleocapsid (anti-N) antibodies. Antibody prevalence was described across age groups. In addition, we performed multivariable logistic regression to identify baseline characteristics independently associated with non-vaccination and described reasons for non-vaccination. RESULTS: Among 22,438 eligible employees, 3,436 (15%) participated; the median age was 43.7 years (range 16-73), 2,794 (81.3%) were female, and 1,407 (47.7%) identified as nurses; 3,414 (99.4%) underwent serology testing, among whom 3,383 (99.0%) had detectable anti-S (3,357, 98.3%) antibodies, anti-N (2,396, 70.1%) antibodies, or both (2,370, 69.4%). A total of 296 (8.6%) healthcare workers were unvaccinated, whereas 3,140 (91.4%) were vaccinated. In multivariable analysis, age (adjusted OR [aOR] 1.02 per year, 95% CI 1.01-1.03), being a physician (aOR 3.22, 95% CI 1.75-5.92) or administrator (aOR 1.88, 95% CI 1.27-2.80), and having higher education (aOR 2.23, 95% CI 1.09-4.57) were positively associated with vaccine uptake, whereas working in non-acute care (aOR 0.58, 95% CI 0.34-0.97), active smoking (aOR 0.68, 95% CI 0.51-0.91), and taking prophylactic home remedies against SARS-CoV-2 (aOR 0.42, 95% CI 0.31-0.56) were negatively associated. Important reasons for non-vaccination were a belief that the vaccine might not have long-lasting immunity (267/291, 92.1%) and a preference for gaining naturally acquired instead of vaccine-induced immunity (241/289, 83.4%). CONCLUSIONS: Almost all healthcare workers in our cohort had specific antibodies against SARS-CoV-2 from natural infection and/or from vaccination. Young healthcare workers and those working in non-acute settings were less likely to be vaccinated, whereas physicians and administrative staff showed higher vaccination uptake. Presumed ineffectiveness of the vaccine is an important reason for non-vaccination.

Impact of shift work and other work-related factors on anti-SARS-CoV-2 spike-protein serum concentrations in healthcare workers after primary mRNA vaccination - a retrospective cohort study.

BACKGROUND: Knowing whether shift work negatively affects the immune system's response to COVID-19 vaccinations could be valuable for planning future vaccination campaigns for healthcare workers. We aimed to determine the impact of working late or night shifts on serum anti-SARS-CoV-2 spike protein immunoglobulin G (anti-S) antibody levels after primary SARS-CoV-2-mRNA vaccination. METHODS: To obtain detailed information on shift work, we sent a separate online questionnaire to 1475 eligible healthcare workers who participated in a prospective longitudinal study conducted in 15 healthcare institutions in Switzerland. We asked all vaccinated healthcare workers with available anti-S antibody levels after vaccination to complete a brief online survey on their working schedules within one week before and after primary mRNA vaccination. We used multivariate regression to evaluate the association between work shifts around primary vaccination and anti-S antibody levels. We adjusted for confounders already known to influence vaccine efficacy (e.g. age, sex, immunosuppression, and obesity) and for variables significant at the 0.05 alpha level in the univariate analyses. RESULTS: The survey response rate was 43% (n = 638). Ninety-eight responders were excluded due to unknown vaccination dates, different vaccines, or administration of the second dose shortly (within 14 days) after or before serologic follow-up. Of the 540 healthcare workers included in our analysis, 175 (32.4%) had worked at least one late or night shift within seven days before and/or after primary vaccination. In the univariate analyses, working late or night shifts was associated with a nonsignificant -15.1% decrease in serum anti-S antibody levels (p = 0.090). In the multivariate analysis, prior infection (197.2% increase; p <0.001) and immunisation with the mRNA-1273 vaccine (63.7% increase compared to the BNT162b2 vaccine; p <0.001) were the strongest independent factors associated with increased anti-S antibody levels. However, the impact of shift work remained statistically nonsignificant (-13.5%, p = 0.108). CONCLUSION: Working late or night shifts shortly before or after mRNA vaccination against COVID-19 does not appear to significantly impact serum anti-S antibody levels. This result merits consideration since it supports flexible vaccination appointments for healthcare workers, including those working late or night shifts.

Association between the introduction of a national targeted intervention program and the incidence of surgical site infections in Swiss acute care hospitals.

BACKGROUND: In Switzerland, the national surgical site infection (SSI) surveillance program showed a modest decrease in SSI rates for different procedures over the last decade. The study aimed to determine whether a multimodal, targeted intervention program in addition to existing SSI surveillance is associated with decreased SSI rates in the participating hospitals. METHODS: Prospective multicenter pre- and postintervention study conducted in eight Swiss acute care hospitals between 2013 and 2020. All consecutive patients > 18 years undergoing cardiac, colon, or hip/knee replacement surgery were included. The follow-up period was 30 days and one year for implant-related surgery. Patients with at least one follow-up were included. The intervention was to optimize three elements of preoperative management: (i) hair removal; (ii) skin disinfection; and (iii) perioperative antimicrobial prophylaxis. We compared SSI incidence rates (main outcome measure) pre- and postintervention (three years each) adjusted for potential confounders. Poisson generalized linear mixed models fitted to quarter-yearly confirmed SSIs and adjusted for baseline differences between hospitals and procedures. Adherence was routinely monitored through on-site visits. RESULTS: A total of 10 151 patients were included, with a similar median age pre- and postintervention (69.6 and IQR 60.9, 76.8 years, vs 69.5 and IQR 60.4, 76.8 years, respectively; P = 0.55) and similar proportions of females (44.8% vs. 46.1%, respectively; P = 0.227). Preintervention, 309 SSIs occurred in 5 489 patients (5.6%), compared to 226 infections in 4 662 cases (4.8%, P = 0.09) postintervention. The adjusted incidence rate ratio (aIRR) for overall SSI after intervention implementation was 0.81 (95% CI, 0.68 to 0.96, P = 0.02). For cardiac surgery (n = 2 927), the aIRR of SSI was 0.48 (95% CI, 0.32 to 0.72, P < 0.001). For hip/knee replacement surgery (n = 4 522), the aIRR was 0.88 (95% CI, 0.52 to 1.48, P = 0.63), and for colon surgery (n = 2 702), the aIRR was 0.92 (95% CI, 0.75 to 1.14, P = 0.49). CONCLUSIONS: The SSI intervention bundle was associated with a statistically significant decrease in SSI cases. A significant association was observed for cardiac surgery. Adding a specific intervention program can add value compared to routine surveillance only. Further prevention modules might be necessary for colon and orthopedic surgery.

Treatment effect of remdesivir on the mortality of hospitalised COVID-19 patients in Switzerland across different patient groups: a tree-based model analysis.

AIMS OF THE STUDY: Remdesivir has shown benefits against COVID-19. However, it remains unclear whether, to what extent, and among whom remdesivir can reduce COVID-19-related mortality. We explored whether the treatment response to remdesivir differed by patient characteristics. METHODS: We analysed data collected from a hospital surveillance study conducted in 21 referral hospitals in Switzerland between 2020 and 2022. We applied model-based recursive partitioning to group patients by the association between treatment levels and mortality. We included either treatment (levels: none, remdesivir within 7 days of symptom onset, remdesivir after 7 days, or another treatment), age and sex, or treatment only as regression variables. Candidate partitioning variables included a range of risk factors and comorbidities (and age and sex unless included in regression). We repeated the analyses using local centring to correct the results for the propensity to receive treatment. RESULTS: Overall (n = 21,790 patients), remdesivir within 7 days was associated with increased mortality (adjusted hazard ratios 1.28-1.54 versus no treatment). The CURB-65 score caused the most instability in the regression parameters of the model. When adjusted for age and sex, patients receiving remdesivir within 7 days of onset had higher mortality than those not treated in all identified eight patient groups. When age and sex were included as partitioning variables instead, the number of groups increased to 19-20; in five to six of those branches, mortality was lower among patients who received early remdesivir. Factors determining the groups where remdesivir was potentially beneficial included the presence of oncological comorbidities, male sex, and high age. CONCLUSIONS: Some subgroups of patients, such as individuals with oncological comorbidities or elderly males, may benefit from remdesivir.

Validation of sTREM-1 and IL-6 based algorithms for outcome prediction of COVID-19.

BACKGROUND: A prospective observational cohort study of COVID-19 patients in a single Emergency Department (ED) showed that sTREM-1- and IL-6-based algorithms were highly predictive of adverse outcome (Van Singer et al. J Allergy Clin Immunol 2021). We aim to validate the performance of these algorithms at ED presentation. METHODS: This multicentric prospective observational study of PCR-confirmed COVID-19 adult patients was conducted in the ED of three Swiss hospitals. Data of the three centers were retrospectively completed and merged. We determined the predictive accuracy of the sTREM-1-based algorithm for 30-day intubation/mortality. We also determined the performance of the IL-6-based algorithm using data from one center for 30-day oxygen requirement. RESULTS: 373 patients were included in the validation cohort, 139 (37%) in Lausanne, 93 (25%) in St.Gallen and 141 (38%) in EOC. Overall, 18% (93/373) patients died or were intubated by day 30. In Lausanne, 66% (92/139) patients required oxygen by day 30. The predictive accuracy of sTREM-1 and IL-6 were similar compared to the derivation cohort. The sTREM-1-based algorithm confirmed excellent sensitivity (90% versus 100% in the derivation cohort) and negative predictive value (94% versus 100%) for 30-day intubation/mortality. The IL-6-based algorithm performance was acceptable with a sensitivity of 85% versus 98% in the derivation cohort and a negative predictive value of 60% versus 92%. CONCLUSION: The sTREM-1 algorithm demonstrated good reproducibility. A prospective randomized controlled trial, comparing outcomes with and without the algorithm, is necessary to assess its safety and impact on hospital and ICU admission rates. The IL-6 algorithm showed acceptable validity in a single center and need additional validation before widespread implementation.

Timing of Cefuroxime Surgical Antimicrobial Prophylaxis and Its Association With Surgical Site Infections.

Importance: World Health Organization guidelines recommend administering surgical antimicrobial prophylaxis (SAP), including cefuroxime, within 120 minutes prior to incision. However, data from clinical settings supporting this long interval is limited. Objective: To assess whether earlier vs later timing of administration of cefuroxime SAP is associated with the occurrence of surgical site infections (SSI). Design, Setting, and Participants: This cohort study included adult patients who underwent 1 of 11 major surgical procedures with cefuroxime SAP, documented by the Swissnoso SSI surveillance system between January 2009 and December 2020 at 158 Swiss hospitals. Data were analyzed from January 2021 to April 2023. Exposures: Timing of cefuroxime SAP administration before incision was divided into 3 groups: 61 to 120 minutes before incision, 31 to 60 minutes before incision, and 0 to 30 minutes before incision. In addition, a subgroup analysis was performed with time windows of 30 to 55 minutes and 10 to 25 minutes as a surrogate marker for administration in the preoperating room vs in the operating room, respectively. The timing of SAP administration was defined as the start of the infusion obtained from the anesthesia protocol. Main Outcomes and Measures: Occurrence of SSI according to Centers for Disease Control and Prevention definitions. Mixed-effects logistic regression models adjusted for institutional, patient, and perioperative variables were applied. Results: Of 538 967 surveilled patients, 222 439 (104 047 men [46.8%]; median [IQR] age, 65.7 [53.9-74.2] years), fulfilled inclusion criteria. SSI was identified in 5355 patients (2.4%). Cefuroxime SAP was administered 61 to 120 minutes prior to incision in 27 207 patients (12.2%), 31 to 60 minutes prior to incision in 118 004 patients (53.1%), and 0 to 30 minutes prior to incision in 77 228 patients (34.7%). SAP administration at 0 to 30 minutes was significantly associated with a lower SSI rate (adjusted odds ratio [aOR], 0.85; 95% CI, 0.78-0.93; P < .001), as was SAP administration 31 to 60 minutes prior to incision (aOR, 0.91; 95% CI, 0.84-0.98; P = .01) compared with administration 61 to 120 minutes prior to incision. Administration 10 to 25 minutes prior to incision in 45 448 patients (20.4%) was significantly associated with a lower SSI rate (aOR, 0.89; 95% CI, 0.82-0.97; P = .009) vs administration within 30 to 55 minutes prior to incision in 117 348 patients (52.8%). Conclusions and Relevance: In this cohort study, administration of cefuroxime SAP closer to the incision time was associated with significantly lower odds of SSI, suggesting that cefuroxime SAP should be administrated within 60 minutes prior to incision, and ideally within 10 to 25 minutes.

Clinical symptoms of SARS-CoV-2 breakthrough infection during the Omicron period in relation to baseline immune status and booster vaccination-A prospective multicentre cohort of health professionals (SURPRISE study).

The effects of different types of pre-existing immunity on the frequency of clinical symptoms caused by the SARS-CoV-2 breakthrough infection were prospectively assessed in healthcare workers during the Omicron period. Among 518 participants, hybrid immunity was associated with symptom reduction for dizziness, muscle or limb pain and headache as compared to vaccination only. Moreover, the frequencies of dizziness, cough and muscle or limb pain were lower in participants who had received a booster vaccine dose. Thus, hybrid immunity appeared to be superior in preventing specific symptoms during breakthrough infection compared to vaccination alone. A booster vaccine dose conferred additional symptom reduction.

Post-Acute Sequelae After Severe Acute Respiratory Syndrome Coronavirus 2 Infection by Viral Variant and Vaccination Status: A Multicenter Cross-Sectional Study.

BACKGROUND: Disentangling the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and vaccination on the occurrence of post-acute sequelae of SARS-CoV-2 (PASC) is crucial to estimate and reduce the burden of PASC. METHODS: We performed a cross-sectional analysis (May/June 2022) within a prospective multicenter healthcare worker (HCW) cohort in north-eastern Switzerland. HCWs were stratified by viral variant and vaccination status at time of their first positive SARS-CoV-2 nasopharyngeal swab. HCWs without positive swab and with negative serology served as controls. The sum of 18 self-reported PASC symptoms was modeled with univariable and multivariable negative-binomial regression to analyze the association of mean symptom number with viral variant and vaccination status. RESULTS: Among 2912 participants (median age: 44 years; 81.3% female), PASC symptoms were significantly more frequent after wild-type infection (estimated mean symptom number: 1.12; P < .001; median time since infection: 18.3 months), after Alpha/Delta infection (0.67 symptoms; P < .001; 6.5 months), and after Omicron BA.1 infections (0.52 symptoms; P = .005; 3.1 months) versus uninfected controls (0.39 symptoms). After Omicron BA.1 infection, the estimated mean symptom number was 0.36 for unvaccinated individuals versus 0.71 with 1-2 vaccinations (P = .028) and 0.49 with ≥3 prior vaccinations (P = .30). Adjusting for confounders, only wild-type (adjusted rate ratio [aRR]: 2.81; 95% confidence interval [CI]: 2.08-3.83) and Alpha/Delta infections (aRR: 1.93; 95% CI: 1.10-3.46) were significantly associated with the outcome. CONCLUSIONS: Previous infection with pre-Omicron variants was the strongest risk factor for PASC symptoms among our HCWs. Vaccination before Omicron BA.1 infection was not associated with a clear protective effect against PASC symptoms in this population.

Risk and symptoms of COVID-19 in health professionals according to baseline immune status and booster vaccination during the Delta and Omicron waves in Switzerland-A multicentre cohort study.

BACKGROUND: Knowledge about protection conferred by previous Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and/or vaccination against emerging viral variants allows clinicians, epidemiologists, and health authorities to predict and reduce the future Coronavirus Disease 2019 (COVID-19) burden. We investigated the risk and symptoms of SARS-CoV-2 (re)infection and vaccine breakthrough infection during the Delta and Omicron waves, depending on baseline immune status and subsequent vaccinations. METHODS AND FINDINGS: In this prospective, multicentre cohort performed between August 2020 and March 2022, we recruited hospital employees from ten acute/nonacute healthcare networks in Eastern/Northern Switzerland. We determined immune status in September 2021 based on serology and previous SARS-CoV-2 infections/vaccinations: Group N (no immunity); Group V (twice vaccinated, uninfected); Group I (infected, unvaccinated); Group H (hybrid: infected and ≥1 vaccination). Date and symptoms of (re)infections and subsequent (booster) vaccinations were recorded until March 2022. We compared the time to positive SARS-CoV-2 swab and number of symptoms according to immune status, viral variant (i.e., Delta-dominant before December 27, 2021; Omicron-dominant on/after this date), and subsequent vaccinations, adjusting for exposure/behavior variables. Among 2,595 participants (median follow-up 171 days), we observed 764 (29%) (re)infections, thereof 591 during the Omicron period. Compared to group N, the hazard ratio (HR) for (re)infection was 0.33 (95% confidence interval [CI] 0.22 to 0.50, p < 0.001) for V, 0.25 (95% CI 0.11 to 0.57, p = 0.001) for I, and 0.04 (95% CI 0.02 to 0.10, p < 0.001) for H in the Delta period. HRs substantially increased during the Omicron period for all groups; in multivariable analyses, only belonging to group H was associated with protection (adjusted HR [aHR] 0.52, 95% CI 0.35 to 0.77, p = 0.001); booster vaccination was associated with reduction of breakthrough infection risk in groups V (aHR 0.68, 95% CI 0.54 to 0.85, p = 0.001) and H (aHR 0.67, 95% CI 0.45 to 1.00, p = 0.048), largely observed in the early Omicron period. Group H (versus N, risk ratio (RR) 0.80, 95% CI 0.66 to 0.97, p = 0.021) and participants with booster vaccination (versus nonboosted, RR 0.79, 95% CI 0.71 to 0.88, p < 0.001) reported less symptoms during infection. Important limitations are that SARS-CoV-2 swab results were self-reported and that results on viral variants were inferred from the predominating strain circulating in the community at that time, rather than sequencing. CONCLUSIONS: Our data suggest that hybrid immunity and booster vaccination are associated with a reduced risk and reduced symptom number of SARS-CoV-2 infection during Delta- and Omicron-dominant periods. For previously noninfected individuals, booster vaccination might reduce the risk of symptomatic Omicron infection, although this benefit seems to wane over time.

Impact of the COVID-19 Pandemic on Inpatient Antibiotic Consumption in Switzerland.

The aim of this study was to analyze inpatient antibiotic consumption during the first 16 months of the COVID-19 pandemic in Switzerland. The entire period (January 2018−June 2021) was divided into the prepandemic period, the first and second waves, and the intermediate period. In the first year of the pandemic, total overall inpatient antibiotic consumption measured in defined daily doses (DDD) per 100 bed-days remained stable (+1.7%), with a slight increase in ICUs of +4.2%. The increase in consumption of broad-spectrum antibiotics was +12.3% overall and 17.3% in ICUs. The segmented regression model of monthly data revealed an increase in overall antibiotic consumption during the first wave but not during the second wave. In the correlation analysis performed in a subset of the data, a significant positive association was found between broad-spectrum antibiotic consumption and an increasing number of hospitalized COVID-19 patients (p = 0.018). Restricting this dataset to ICUs, we found significant positive correlations between the number of hospitalized COVID-19 patients and total antibiotic consumption (p = 0.007) and broad-spectrum antibiotic consumption (p < 0.001). In conclusion, inpatient antibiotic use during the different periods of the COVID-19 pandemic varied greatly and was predominantly notable for broad-spectrum antibiotics.

Measuring perception of mental well-being in patients under isolation precautions: a prospective comparative study.

OBJECTIVES: Isolation precautions (IP) are applied to prevent transmission of pathogens in healthcare settings. Potential negative health outcomes experienced by patients have been previously described but results remain conflicting. We aimed at evaluating the psychological impact of IP in adult patients in isolation using a novel psychological assessment tool. STUDY DESIGN: Prospective matched cohort study. SETTING: Tertiary care centre in Switzerland. PARTICIPANTS: Hospitalised patients under IP and non-isolated patients were matched by ward, age and illness severity. OUTCOME MEASURES: We measured surrogates of mental and social well-being by using the Pictorial Representation of Illness and Self Measure (PRISM) instrument once during hospitalisation. PRISM is a visual psychometric instrument that has been validated as a quantitative measure of suffering. Smaller distance in self-to-illness separation (SIS) signifies higher importance for a patient. RESULTS: 156 patients agreed to participate of which 63 were under IP and 93 were matched controls. Median (IQR) duration of isolation was 5 days (2-10). The median SIS (IQR) for perceived inferior nurses' care was 22.8 (18.5-24.3) and 23.8 (23.3-25.5) for isolated and non-isolated patients, respectively (p<0.001). Similarly, median SIS (IQR) was significantly smaller in isolated than non-isolated patients for avoidance by visitors with 17.5 (7.7-22.0) and 22.2 (21.8-22.6), for loneliness with 7.5 (3.6-16.0) and 18 (10.2-21.6) and for feeling impure with 19 (17.0-21.5) and 21.5 (18.9-22.1), respectively (all p values<0.05). CONCLUSIONS: IP to prevent transmission of pathogens may negatively impact mental and social well-being. Measures to alleviate adverse effects of IP should be taken routinely.

Impact of respirator versus surgical masks on SARS-CoV-2 acquisition in healthcare workers: a prospective multicentre cohort.

BACKGROUND: There is insufficient evidence regarding the role of respirators in the prevention of SARS-CoV-2 infection. We analysed the impact of filtering facepiece class 2 (FFP2) versus surgical masks on the risk of SARS-CoV-2 acquisition among Swiss healthcare workers (HCW). METHODS: Our prospective multicentre cohort enrolled HCW from June to August 2020. Participants were asked about COVID-19 risk exposures/behaviours, including preferentially worn mask type when caring for COVID-19 patients outside of aerosol-generating procedures. The impact of FFP2 on (1) self-reported SARS-CoV-2-positive nasopharyngeal PCR/rapid antigen tests captured during weekly surveys, and (2) SARS-CoV-2 seroconversion between baseline and January/February 2021 was assessed. RESULTS: We enrolled 3259 participants from nine healthcare institutions, whereof 716 (22%) preferentially used FFP2. Among these, 81/716 (11%) reported a SARS-CoV-2-positive swab, compared to 352/2543 (14%) surgical mask users; seroconversion was documented in 85/656 (13%) FFP2 and 426/2255 (19%) surgical mask users. Adjusted for baseline characteristics, COVID-19 exposure, and risk behaviour, FFP2 use was non-significantly associated with decreased risk for SARS-CoV-2-positive swab (adjusted hazard ratio [aHR] 0.8, 95% CI 0.6-1.0) and seroconversion (adjusted odds ratio [aOR] 0.7, 95% CI 0.5-1.0); household exposure was the strongest risk factor (aHR 10.1, 95% CI 7.5-13.5; aOR 5.0, 95% CI 3.9-6.5). In subgroup analysis, FFP2 use was clearly protective among those with frequent (> 20 patients) COVID-19 exposure (aHR 0.7 for positive swab, 95% CI 0.5-0.8; aOR 0.6 for seroconversion, 95% CI 0.4-1.0). CONCLUSIONS: Respirators compared to surgical masks may convey additional protection from SARS-CoV-2 for HCW with frequent exposure to COVID-19 patients.

Providing care to patients in contact isolation: is the systematic use of gloves still indicated?

This article reviews the available evidence on the effectiveness of gloves in preventing infection during care provided to patients under contact precautions, and analyses the risks and benefits of their systematic use. Although hand hygiene with alcohol-based handrub was shown to be effective in preventing nosocomial infections, many publications put the effectiveness and usefulness of gloves into perspective. Instead, literature and various unpublished experiences point towards reduced hand hygiene compliance and increased risk of spreading pathogens with routine glove use. Therefore, hospitals should emphasise hand hygiene in their healthcare staff and, instead of the routine use of gloves when caring for patients under contact precautions, limit their use to the indications of standard precautions, i.e., mainly for contact with body fluids. Wide and easy access to alcohol-based handrub and continual teaching are essential. If such conditions are met and adherence to hand hygiene is excellent and regularly assessed, the routine use of gloves for patients under contact precautions seems no longer indicated.

Symptoms Compatible With Long Coronavirus Disease (COVID) in Healthcare Workers With and Without Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection-Results of a Prospective Multicenter Cohort.

BACKGROUND: The burden of long-term symptoms (ie, long COVID) in patients after mild COVID-19 is debated. Within a cohort of healthcare workers (HCWs), frequency and risk factors for symptoms compatible with long COVID are assessed. METHODS: Participants answered baseline (August/September 2020) and weekly questionnaires on SARS-CoV-2 nasopharyngeal swab (NPS) results and acute disease symptoms. In January 2021, SARS-CoV-2 serology was performed; in March, symptoms compatible with long COVID (including psychometric scores) were asked and compared between HCWs with positive NPS, seropositive HCWs without positive NPS (presumable asymptomatic/pauci-symptomatic infections), and negative controls. The effect of time since diagnosis and quantitative anti-spike protein antibodies (anti-S) was evaluated. Poisson regression was used to identify risk factors for symptom occurrence. RESULTS: Of 3334 HCWs (median, 41 years; 80% female), 556 (17%) had a positive NPS and 228 (7%) were only seropositive. HCWs with positive NPS more frequently reported ≥1 symptom compared with controls (73% vs 52%, P < .001); seropositive HCWs without positive NPS did not score higher than controls (58% vs 52%, P = .13), although impaired taste/olfaction (16% vs 6%, P < .001) and hair loss (17% vs 10%, P = .004) were more common. Exhaustion/burnout was reported by 24% of negative controls. Many symptoms remained elevated in those diagnosed >6 months ago; anti-S titers correlated with high symptom scores. Acute viral symptoms in weekly questionnaires best predicted long-COVID symptoms. Physical activity at baseline was negatively associated with neurocognitive impairment and fatigue scores. CONCLUSIONS: Seropositive HCWs without positive NPS are only mildly affected by long COVID. Exhaustion/burnout is common, even in noninfected HCWs. Physical activity might be protective against neurocognitive impairment/fatigue symptoms after COVID-19.