Surveillance and identification of clusters of healthcare workers with coronavirus disease 2019 (COVID-19): Multidimensional interventions at a comprehensive cancer center

Quantifying hospital environmental ventilation using carbon dioxide monitoring - a multicentre study

The COVID-19 pandemic has highlighted the importance of environmental ventilation in reducing airborne pathogen transmission. Carbon dioxide monitoring is recommended in the community to ensure adequate ventilation. Dynamic measurements of ventilation quantifying human exhaled waste gas accumulation are not conducted routinely in hospitals. Instead, environmental ventilation is allocated using static hourly air change rates. These vary according to the degree of perceived hazard, with the highest change rates reserved for locations where aerosol-generating procedures are performed, where medical/anaesthetic gases are used and where a small number of high-risk infective or immunocompromised patients may be isolated to reduce cross-infection. We aimed to quantify the quality and distribution of ventilation in hospital by measuring carbon dioxide levels in a two-phased prospective observational study. First, under controlled conditions, we validated our method and the relationship between human occupancy, ventilation and carbon dioxide levels using non-dispersive infrared carbon dioxide monitors. We then assessed ventilation quality in patient-occupied (clinical) and staff break and office (non-clinical) areas across two hospitals in Scotland. We selected acute medical and respiratory wards in which patients with COVID-19 are cared for routinely, as well as ICUs and operating theatres where aerosol-generating procedures  are performed routinely. Between November and December 2022, 127,680 carbon dioxide measurements were obtained across 32 areas over 8 weeks. Carbon dioxide levels breached the 800 ppm threshold for 14% of the time in non-clinical areas vs. 7% in clinical areas (p < 0.001). In non-clinical areas, carbon dioxide levels were > 800 ppm for 20% of the time in both ICUs and wards, vs. 1% in operating theatres (p < 0.001). In clinical areas, carbon dioxide was > 800 ppm for 16% of the time in wards, vs. 0% in ICUs and operating theatres (p < 0.001). We conclude that staff break, office and clinical areas on acute medical and respiratory wards frequently had inadequate ventilation, potentially increasing the risks of airborne pathogen transmission to staff and patients. Conversely, ventilation was consistently high in the ICU and operating theatre clinical environments. Carbon dioxide monitoring could be used to measure and guide improvements in hospital ventilation.

Genomic Investigation to Identify Sources of Severe Acute Respiratory Syndrome Coronavirus 2 Infection Among Healthcare Personnel in an Acute Care Hospital

Background

Identifying the source of healthcare personnel (HCP) coronavirus disease 2019 (COVID-19) is important to guide occupational safety efforts. We used a combined whole genome sequencing (WGS) and epidemiologic approach to investigate the source of HCP COVID-19 at a tertiary-care center early in the COVID-19 pandemic.

Methods

Remnant nasopharyngeal swab samples from HCP and patients with polymerase chain reaction-proven COVID-19 from a period with complete sample retention (14 March 2020 to 10 April 2020) at Rush University Medical Center in Chicago, Illinois, underwent viral RNA extraction and WGS. Genomes with >90% coverage underwent cluster detection using a 2 single-nucleotide variant genetic distance cutoff. Genomic clusters were evaluated for epidemiologic linkages, with strong linkages defined by evidence of time/location overlap.

Results

We analyzed 1031 sequences, identifying 49 clusters that included ≥1 HCP (265 patients, 115 HCP). Most HCP infections were not healthcare associated (88/115 [76.5%]). We did not identify any strong epidemiologic linkages for patient-to-HCP transmission. Thirteen HCP cases (11.3%) were attributed to a potential patient source (weak evidence involving nonclinical staff that lacked location data to prove or disprove contact with patients in same cluster). Fourteen HCP cases (12.2%) were attributed to HCP source (11 with strong evidence).

Conclusions

Using genomic and epidemiologic data, we found that most HCP severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were not healthcare associated. We did not find strong evidence of patient-to-HCP transmission of SARS-CoV-2.

Identifying Contact Risks for SARS-CoV-2 Transmission to Healthcare Workers during Outbreak on COVID-19 Ward

We assessed the risk for different exposures to SARS-CoV-2 during a COVID-19 outbreak among healthcare workers on a hospital ward in late 2020. We found working with isolated COVID-19 patients did not increase the risk of COVID-19 among workers, but working shifts with presymptomatic healthcare coworkers did.

Lessons learned from an outbreak of COVID-19 in the head and neck surgery ward of a Japanese cancer center during the sixth wave by Omicron

Introduction

We describe a coronavirus disease (COVID-19) outbreak in a cancer center's head and neck surgery ward and the interventions to halt ongoing exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among healthcare workers and patients with cancer.

Methods

Case definition included all healthcare workers and all patients associated to the ward from January 27 to January 31, 2022 with a positive SARS-COV-2 antigen test. This retrospective descriptive study was conducted between January 27, 2022, and February 14, 2022.

Results

From January 28, 2022, to February 9, 2022, 84 cases (36 healthcare workers, 48 patients) were screened, and 26 (12 healthcare workers, 14 patients) were identified as SARS-CoV-2-positive. The proportion of healthcare providers who performed aerosol generating procedures on positive patients was 91% for positive cases and 49% for non-cases. Room sharing with patients with COVID-19 was 64% for positive cases and 21% for non-cases (57% vs. 21% with positive tracheostomy patients; 43% vs. 9% with positive cases using a nebulizer; 50% vs. 15% with positive cases requiring sputum suctioning, respectively). Compliance with the universal masking policy for patients was 36% of positive cases and 79% of non-cases.

Conclusions

This is the first report of a nosocomial outbreak of COVID-19 in a head and neck surgery ward during the Omicron pandemic. Notably, there were a high number of positive cases among healthcare workers who performed aerosol generating procedures for positive patients and patients who shared the room with a patient with COVID-19 with the potential to generate aerosols.

Clustering of Covid-19 Infections among Healthcare Workers: Experience from A Tertiary Care Center in Saudi Arabia

Introduction

Coronavirus infectious disease 2019 (COVID-19) had a significant impact on healthcare workers (HCWs) worldwide. Understanding the dynamics of infection transmission is important to develop strategies to prevent its spread.

Methods

A retrospective study of a cohort of HCWs with COVID-19 from a single tertiary care hospital during the first wave of the pandemic. Epidemiological investigations and identification of clusters of infection were done prospectively.

Results

A total of 326 HCWs had COVID-19 based on positive polymerase chain reaction tests for SARS-CoV-2. Ten clusters of infection were identified; nine clusters had HCWs as the index cases while one cluster had a patient as the index case. The largest cluster involved 15 transmissions, and one cluster included a secondary transmission. Sharing accommodation and social gatherings were the commonest epidemiological links. The majority of infected HCWs had mild infections, 23 (6%) required hospital admission and 3 (1%) required intensive care; all fully recovered. Majority of infections (80%) were community-acquired. Living in shared accommodation was associated with COVID-19 (120/690 versus 206/1610, P value = .01) while working in COVID-19 designated wards/units was not associated with COVID-19 (52/297 vs 274/2003, P value = .13).

Conclusions

Clustering of COVID-19 was common among HCWs and related to shared accommodation and social gatherings, infection was of mild severity, and was not associated with caring for COVID-19 patients.

Infection Prevention and Control of Severe Acute Respiratory Syndrome Coronavirus 2 in Health Care Settings

The authors describe infection prevention and control approaches to severe acute respiratory syndrome coronavirus 2 in the health care setting, including a review of the chain of transmission and the hierarchy of controls, which are cornerstones of infection control and prevention. The authors also discuss lessons learned from nosocomial transmission events.

A systems approach to understanding SARS-CoV-2 transmission among healthcare workers in a cluster

Preventing transmission of COVID-19 between healthcare workers is essential to optimize patient, employee, and organizational outcomes. We used a systems engineering approach to analyze contact tracing interviews from a cluster of COVID-19 at our healthcare institution and identified modifiable and non-modifiable causes of transmission. Similar work system analyses may be useful to institutions in identifying multiple factors contributing to infection clusters among healthcare workers, and in developing layered infection prevention methods to further reduce transmission.

SARS-CoV-2 outbreak in a Canadian suburban tertiary hospital necessitating full facility closure: a descriptive observational study

BACKGROUND

SARS-CoV-2 can cause outbreaks in community- and hospital-based settings. The aim of this study was to provide a detailed epidemiologic account of a hospital-wide SARS-CoV-2 outbreak and provide a description of case evaluations, transmission networks and the interventions implemented to stem the outbreak.

METHODS

We conducted a retrospective descriptive study of a hospital-wide SARS-CoV-2 outbreak at the Misericordia Community Hospital (Edmonton) from June 21 to Aug. 14, 2020. We reviewed hospital chart, public health and occupational health records to determine demographics, case type (community- or hospital-acquired), need for critical care and outcome for each case linked to the outbreak (patients, hospital staff, and community and patient visitors). We developed detailed transmission networks using epidemiologic data to determine what variables may have contributed to transmission.

RESULTS

Fifty-eight cases of SARS-CoV-2 infection were linked to this hospital outbreak (31 patients, 25 staff members and 2 visitors; 66% female, age range 19-97 years). One patient required critical care, and 11 deaths were recorded (all among inpatients). Most cases were hospital-acquired (91%), and 28% were asymptomatic at the time of diagnosis. The outbreak was composed of 2 clusters driven by protective equipment breaches, premature removal of precautions, transmission in small staff quarters and infection of a staff member after exposure to a wandering patient with dementia and asymptomatic, undetected SARS-CoV-2 infection.

INTERPRETATION

A detailed epidemiologic review of this hospital-wide outbreak shows that a SARS-CoV-2 outbreak can involve complex transmission chains and clusters. Multipronged bundled approaches, aggressive contact tracing, and patient and staff prevalence screening are important to help bring such outbreaks under control, along with ongoing vigilance in detecting delayed cases.

Infection preventionists' experiences during the first nine months of the COVID-19 pandemic: Findings from focus groups conducted with Association of Professionals in Infection Control & Epidemiology (APIC) members

INTRODUCTION

A novel human Coronavirus (SARS CoV-2) was identified in January, 2020 and developed into a pandemic by March, 2020. This rapid, enormous, and unanticipated event had major implications for healthcare. Infection preventionists (IP) have a critical role in worker and patient safety. IPs' lessons learned can guide future pandemic response.

METHODS

Seven focus groups were conducted with APIC members in September and October, 2020 via Zoom to elicit IPs' experiences during the COVID-19 pandemic. Sessions were recorded then transcribed verbatim. Major themes were identified through content analysis.

RESULTS

In total, 73 IPs participated (average of 10 IPs per focus group) and represented all geographical areas and work settings. Participating IPs described multiple challenges they have faced during the COVID-19 pandemic, including rapidly changing and conflicting guidance, a lack of infection prevention recommendations for nonacute care settings, insufficient personal protective equipment, healthcare personnel complacency with personal protective equipment and infection prevention protocols, and increases in healthcare associated infections and workload.

CONCLUSIONS

The identified gaps in pandemic response need to be addressed in order to minimize healthcare associated infections and occupational illness. In addition, the educational topics identified by the participating IPs should be developed into new educational programs and resources.

Risk of Healthcare-Associated Transmission of SARS-CoV-2 in Hospitalized Cancer Patients

Background

There is limited information on the risk of hospital-acquired coronavirus disease 2019 (COVID-19) among high-risk hospitalized patients after exposure to an infected patient or healthcare worker (HCW) in a nonoutbreak setting.

Methods

This study was conducted at a tertiary care cancer center in New York City from 10 March 2020 until 28 February 2021. In early April 2020, the study institution implemented universal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing at admission and retesting every 3 days through the hospital stay. Contact tracing records were reviewed for all exposures to SARS-CoV-2 positive patients and HCWs.

Results

From 10 March 2020 to 28 February 2021, 11 348 unique patients who were SARS-CoV-2 polymerase chain reaction (PCR) negative at the time of admission underwent 31 662 postadmission tests during their hospitalization, and 112 tested positive (0.98%). Among these, 49 patients housed in semiprivate rooms during admission resulted in 74 close contacts and 14 secondary infections within 14 days, for an overall attack rate of 18.9%. Among those exposed to a roommate undergoing an aerosol-generating procedure (AGP), the attack rate was 35.7%. Whole genome sequencing (WGS) corroborated transmission in 6/8 evaluated pairs. In addition, three transmission events occurred in 214 patients with significant exposure to 105 COVID-19 positive healthcare workers (1.4%).

Conclusions

The overall risk of hospital-acquired COVID-19 is low for hospitalized cancer patients, even during periods of high community prevalence. However, shared occupancy with an unrecognized case is associated with a high secondary attack rate in exposed roommates.

Staff to staff transmission as a driver of healthcare worker infections with COVID-19

Background

High rates of healthcare worker (HCW) infections due to COVID-19 have been attributed to several factors, including inadequate personal protective equipment (PPE), exposure to a high density of patients with COVID-19, and poor building ventilation. We investigated an increase in the number of staff COVID-19 infections at our hospital to determine the factors contributing to infection and to implement the interventions required to prevent subsequent infections.

Methods

We conducted a single-centre retrospective cohort study of staff working at a tertiary referral hospital who tested positive for SARS-CoV-2 between 25 January 2020 and 25 November 2020. The primary outcome was the source of COVID-19 infection.

Results

Of 45 staff who returned a positive test result for SARS-CoV-2, 19 were determined to be acquired at our hospital. Fifteen (15/19; 79% [95% CI: 54–94%]) of these were identified through contact tracing and testing following exposures to other infected staff and were presumed to be staff-to-staff transmission, including an outbreak in 10 healthcare workers (HCWs) linked to a single ward that cared for COVID-19 patients. The staff tearoom was identified as the likely location for transmission, with subsequent reduction in HCW infections and resolution of the outbreak following implementation of enhanced control measures in tearoom facilities. No HCW contacts (0/204; 0% [95% CI: 0–2%]) developed COVID-19 infection following exposure to unrecognised patients with COVID-19.

Conclusion

Unrecognised infections among staff may be a significant driver of HCW infections in healthcare settings. Control measures should be implemented to prevent acquisition from other staff as well as patient-staff transmission.