Burden of nosocomial COVID-19 in Wales: results from a multicentre retrospective observational study of 2508 hospitalised adults

Risk of SARS-CoV-2 infection in hospitalized patients following SARS-CoV-2 exposures before and during hospitalization

Little is known regarding SARS-CoV-2 infection risk following SARS-CoV-2 exposures in hospitalized patients. Amongst 11,997 patients in 14 hospitals exposed 2020-2023, 6.5% tested positive (median 3d after exposure). Positivity rates were 6.7% vs 5.8% for Omicron vs pre-Omicron exposures (P = 0.07) and 7.6% vs 4.6% for exposures before vs after admission (P < 0.001).

Contact tracing in the hospital setting during the omicron wave of the coronavirus disease 2019 pandemic: persons and periods of concern for nosocomial infection prevention and control

This study evaluating the efficacy of coronavirus disease 2019 contact tracing in the hospital setting during the omicron variant era found a high incidence of nosocomial severe acute respiratory coronavirus virus 2 (SARS-CoV-2) transmission in outbreaks, especially among individuals having close contact with infected persons. Identifying close contacts and outbreaks is essential to prevent nosocomial SARS-CoV-2 transmission.

From wild-type to Omicron: changes in SARS-CoV-2 hospital cluster dynamics. Observations from a German tertiary care hospital

Aim

SARS-CoV-2 hospital clusters are a challenge for healthcare systems. There is an increased risk of infection for both healthcare workers (HCWs) and patients; cluster countermeasures are also a drain on resources for the wards affected. We analysed to which extent characteristics and dynamics of SARS-CoV-2 clusters varied throughout the pandemic at a German university hospital.

Methods

Patient and/or HCW clusters from 10/2020 to 04/2022 were included in the study and grouped by virus variant into i.) clusters comprised of the presumably predominant wild-type, Alpha or Delta (WAD) SARS-COV-2 variants, and ii.) clusters comprised predominantly of Omicron subtype cases. The two groups were compared for specific characteristics and dynamics.

Results

Forty-two SARS-CoV-2 clusters and 528 cases were analysed. Twenty-one clusters and 297 cases were attributed to the WAD and 21 clusters and 231 cases to the Omicron group. There were no significant differences in median size (8 vs. 8 cases, p=0.94) or median duration (14 vs. 12 days; p=0.48), nor in the percentage of HCWs involved (46.8% vs. 50.2%; p=0.48). Patients in the WAD group were older (median 75 vs. 68 years of age; p≤0.05). The median time from cluster onset to case onset was significantly shorter for the Omicron group (median 6 vs. 11 days; p≤0.05).

Conclusions

Omicron clusters exhibited a more rapid dynamic, forcing all parties involved to adapt to the increased workload. Compared to excessive community case counts, constant Omicron cluster-affiliated case counts and stable cluster characteristics suggest an improved compliance with IPC countermeasures.

Nosocomial COVID-19 infection in the era of vaccination and antiviral therapy

BACKGROUND AND AIMS

Coronavirus disease 2019 (COVID-19) vaccination and antiviral therapies have altered the course of the COVID-19 pandemic through mitigating severe illness and death. However, immunocompromised, elderly and multimorbid patients remain at risk of poor outcomes and are overrepresented in hospital populations. The aim of this study was to describe the characteristics and outcomes of patients with nosocomial COVID-19 infection.

METHODS

This was a retrospective, observational study of patients who acquired COVID-19 after 7 days of hospital admission within the Southern Adelaide Local Health Network (SALHN) in South Australia between 1 June 2022 and 30 November 2022. Data were ascertained from the electronic medical record and the South Australian registry of births, deaths and marriages.

RESULTS

Of 1084 COVID-19 inpatient cases managed in SALHN, 295 (27%) were nosocomial, with 215 included in the study. The median age of patients was 80 years (interquartile range [IQR], 68-88 years), the median Charlson Comorbidity Index score was 5 (IQR, 4-7) and 6% were immunocompromised. Most nosocomial COVID-19 infections were of mild severity (81%). The 30-day all-cause mortality rate following COVID-19 infection was 6%, and, in most cases, a cause of death other than COVID-19 was recorded on the death certificate.

CONCLUSION

The majority of cases of nosocomial COVID-19 infection were mild, with a lower mortality rate than in earlier studies. This finding is likely attributable to immunity through vaccination and prior infection, early antiviral therapy and attenuated severity of the Omicron variant. The high proportion of nosocomial infections supports ongoing infection control measures.

COVID-19 managed on respiratory wards and intensive care units: Results from the national COVID-19 outcome report in Wales from March 2020 to December 2021

BACKGROUND

A COVID-19 hospital guideline was implemented across all 18 acute hospitals in Wales in March 2020, promoting ward management of COVID pneumonitis and data collected across the first 3 Waves of the pandemic (Wave 1 March 1st 2020 to November 1st 2020, Wave 2 November 2st 2020 to February 21st 2021 and Wave 3 June 1st 2021 to December 14th 2021). The aim of this paper is to compare outcomes for patients by admission setting and type of ventilatory support given, with a particular focus on CPAP therapy.

METHODS

This is a retrospective observational study of those aged over 18 admitted to hospital with community acquired COVID-19 between March 2020 and December 2021. The outcome of interest was in-hospital mortality. Univariate logistic regression models were used to compare crude outcomes across the waves. Multivariable logistic regression models were used to assess outcomes by different settings and treatments after adjusting for Wave, age, sex, co-morbidity and deprivation.

RESULTS

Of the 7,803 records collected, 5,887 (75.4%) met the inclusion criteria. Analysis of those cases identified statistically significant outcome improvements across the waves for all patients combined (Waves 1 to 3: 31.5% to 18.8%, p<0.01), all ward patients (28.9% to 17.7%, p<0.01), and all ICU patients (44.3% to 32.2%, p = 0.03). Sub group analyses identified outcome improvements in ward patients without any oxygen therapy (Waves 1 to 3: 22.2% to 12.7%, p<0.01), with oxygen therapy only (34.0% to 12.9%, p<0.01) and with CPAP only (63.5% to 39.2%, p<0.01). The outcome improvements for ICU patients receiving CPAP only (35.7% to 24.6%, p = 0.31) or invasive ventilation (61.6% to 54.6%, p = 0.43) were not statistically significant though the numbers being admitted to ICU were small. The logistic regression models identified important age and comorbidity effects on outcomes. The multivariable model that took these into account suggested no statistically significantly greater risk of death for those receiving CPAP on the ward compared to those receiving CPAP in ICU (OR 0.89, 95% CI: 0.49 to 1.60).

CONCLUSIONS

There were successive reductions in mortality in inpatients over the three Waves reflecting new treatments and better management of complications. Mortality for those requiring CPAP was similar in respiratory wards and ICUs after adjusting for differences in their respective patient populations.

Mortality amongst hospitalized COVID-19 cases by acquisition and pandemic wave in Wales, UK, February 2020-March 2022

BACKGROUND

Hospital populations are vulnerable to COVID-19, but the relative severity of hospital acquisition compared to community is unknown. We investigated differences in mortality between hospital and community acquired cases in Wales.

METHODS

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) polymerase chain reaction tests from February 2020 to March 2022 were linked with hospital admissions to identify likely hospital-acquired cases. All-cause mortality within 28 days of a positive SARS-CoV-2 were measured by source of acquisition. Multi-variable logistic regression was used to compare mortality by source of acquisition, adjusting for confounders, computing adjusted odds ratios (aOR) with 95% confidence intervals (CI).

RESULTS

There were 25,263 hospital-acquired cases of COVID-19 and 5490 (22%) deaths in the study period. Although significant on univariate analysis, adjustment for confounding showed no association with increased mortality for hospital-acquired cases compared with cases admitted with COVID-19 (aOR 0.8, 95% CI 0.7-0.8). Vaccination (aOR 0.6, 95% CI 0.5-0.7) and infection in later pandemic waves (aOR 0.5, 95% CI 0.4-0.6) were associated with lower mortality; older age (≥85 vs <25 years: aOR 76.4, 95% CI 41.8-160.5) and male sex (aOR 1.5, 95% CI 1.4-1.6) were associated with higher mortality.

CONCLUSION

One in five hospitalised COVID-19 cases died within a month of infection. Mortality in nosocomial cases was not worse than those admitted with COVID-19, possibly reflecting early identification of nosocomial cases through screening.

The burden and dynamics of hospital-acquired SARS-CoV-2 in England

Hospital-based transmission had a dominant role in Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV) epidemics1,2, but large-scale studies of its role in the SARS-CoV-2 pandemic are lacking. Such transmission risks spreading the virus to the most vulnerable individuals and can have wider-scale impacts through hospital-community interactions. Using data from acute hospitals in England, we quantify within-hospital transmission, evaluate likely pathways of spread and factors associated with heightened transmission risk, and explore the wider dynamical consequences. We estimate that between June 2020 and March 2021 between 95,000 and 167,000 inpatients acquired SARS-CoV-2 in hospitals (1% to 2% of all hospital admissions in this period). Analysis of time series data provided evidence that patients who themselves acquired SARS-CoV-2 infection in hospital were the main sources of transmission to other patients. Increased transmission to inpatients was associated with hospitals having fewer single rooms and lower heated volume per bed. Moreover, we show that reducing hospital transmission could substantially enhance the efficiency of punctuated lockdown measures in suppressing community transmission. These findings reveal the previously unrecognized scale of hospital transmission, have direct implications for targeting of hospital control measures and highlight the need to design hospitals better equipped to limit the transmission of future high-consequence pathogens.

Nosocomial outbreak in a respiratory ward caused by the SARS-CoV-2 Omicron BA 5.2.1 subvariant associated with non-severe illness in vaccinated patients

In this short report, we describe an outbreak of COVID-19 caused by Omicron subvariant BA.5.2.1 in highly vaccinated patients in a respiratory ward in a large acute general hospital in North West London, United Kingdom. The attack rate was high (14/33 (42%)) but the clinical impact was relatively non-severe including in patients who were at high risk of severe COVID-19. Twelve of fourteen patients had COVID-19 vaccinations. There was only one death due to COVID-19 pneumonitis. The findings of this outbreak investigation suggest that while the transmissibility of Omicron BA.5.2.1 subvariant is high, infections caused by this strain are non-severe in vaccinated patients, even if they are at high risk of severe COVID-19 infection.

Rationale for the shielding policy for clinically vulnerable people in the UK during the COVID-19 pandemic: a qualitative study

INTRODUCTION

Shielding aimed to protect those predicted to be at highest risk from COVID-19 and was uniquely implemented in the UK during the first year of the pandemic from March 2020. As the first stage in the EVITE Immunity evaluation (Effects of shielding for vulnerable people during COVID-19 pandemic on health outcomes, costs and immunity, including those with cancer:quasi-experimental evaluation), we generated a logic model to describe the programme theory underlying the shielding intervention.

DESIGN AND PARTICIPANTS

We reviewed published documentation on shielding to develop an initial draft of the logic model. We then discussed this draft during interviews with 13 key stakeholders involved in putting shielding into effect in Wales and England. Interviews were recorded, transcribed and analysed thematically to inform a final draft of the logic model.

RESULTS

The shielding intervention was a complex one, introduced at pace by multiple agencies working together. We identified three core components: agreement on clinical criteria; development of the list of people appropriate for shielding; and communication of shielding advice. In addition, there was a support programme, available as required to shielding people, including food parcels, financial support and social support. The predicted mechanism of change was that people would isolate themselves and so avoid infection, with the primary intended outcome being reduction in mortality in the shielding group. Unintended impacts included negative impact on mental and physical health and well-being. Details of the intervention varied slightly across the home nations of the UK and were subject to minor revisions during the time the intervention was in place.

CONCLUSIONS

Shielding was a largely untested strategy, aiming to mitigate risk by placing a responsibility on individuals to protect themselves. The model of its rationale, components and outcomes (intended and unintended) will inform evaluation of the impact of shielding and help us to understand its effect and limitations.

Did the UK's public health shielding policy protect the clinically extremely vulnerable during the COVID-19 pandemic in Wales? Results of EVITE Immunity, a linked data retrospective study

INTRODUCTION

The UK shielding policy intended to protect people at the highest risk of harm from COVID-19 infection. We aimed to describe intervention effects in Wales at 1 year.

METHODS

Retrospective comparison of linked demographic and clinical data for cohorts comprising people identified for shielding from 23 March to 21 May 2020; and the rest of the population. Health records were extracted with event dates between 23 March 2020 and 22 March 2021 for the comparator cohort and from the date of inclusion until 1 year later for the shielded cohort.

RESULTS

The shielded cohort included 117,415 people, with 3,086,385 in the comparator cohort. The largest clinical categories in the shielded cohort were severe respiratory condition (35.5%), immunosuppressive therapy (25.9%) and cancer (18.6%). People in the shielded cohort were more likely to be female, aged ≥50 years, living in relatively deprived areas, care home residents and frail. The proportion of people tested for COVID-19 was higher in the shielded cohort (odds ratio [OR] 1.616; 95% confidence interval [CI] 1.597-1.637), with lower positivity rate incident rate ratios 0.716 (95% CI 0.697-0.736). The known infection rate was higher in the shielded cohort (5.9% vs 5.7%). People in the shielded cohort were more likely to die (OR 3.683; 95% CI: 3.583-3.786), have a critical care admission (OR 3.339; 95% CI: 3.111-3.583), hospital emergency admission (OR 2.883; 95% CI: 2.837-2.930), emergency department attendance (OR 1.893; 95% CI: 1.867-1.919) and common mental disorder (OR 1.762; 95% CI: 1.735-1.789).

CONCLUSION

Deaths and healthcare utilisation were higher amongst shielded people than the general population, as would be expected in the sicker population. Differences in testing rates, deprivation and pre-existing health are potential confounders; however, lack of clear impact on infection rates raises questions about the success of shielding and indicates that further research is required to fully evaluate this national policy intervention.

Clinical Outcome and Prognosis of a Nosocomial Outbreak of COVID-19

Nosocomial coronavirus disease 2019 (COVID-19) outbreaks have been reported despite widespread quarantine methods to prevent COVID-19 in society and hospitals. Our study was performed to investigate the clinical outcome and prognosis of a nosocomial outbreak of COVID-19. We retrospectively analyzed the medical records of patients diagnosed with nosocomial COVID-19 of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) at a university teaching hospital between 1 November 2021 and 31 April 2022. Nosocomial COVID-19 was defined as a positive SARS-CoV-2 polymerase chain reaction (PCR) test result 4 or more days after admission in asymptomatic patients who had a negative SARS-CoV-2 PCR test on admission. In this study, 167 patients were diagnosed with nosocomial COVID-19 (1.14%) among a total of 14,667 patients admitted to hospital during the study period. A total of 153 patients (91.6%) survived, but 14 patients (8.4%) died. The median time between admission and COVID-19 diagnosis was 11 days, and the median duration of hospital stay was 24 days. After adjusting for other factors, no vaccination (adjusted HR = 5.944, 95% CI = 1.626–21.733, p = 0.007) and chronic kidney disease (adjusted HR = 6.963, 95% CI = 1.182–41.014, p = 0.032) were found to increase mortality risk. Despite strict quarantine, a significant number of nosocomial COVID-19 cases with a relatively high mortality rate were reported. As unvaccinated status or chronic kidney disease were associated with poor outcomes of nosocomial COVID-19, more active preventive strategies and treatments for patients with these risk factors are needed.

Transmission dynamics and associated mortality of nosocomial COVID-19 throughout 2021: a retrospective study at a large teaching hospital in London

BACKGROUND

The impact of nosocomial SARS-CoV-2 infections has changed significantly since 2020. However, there is a lack of up-to-date evidence of the epidemiology of these infections which is essential in order to appropriately guide infection control policy.

AIMS

To identify the secondary attack rate of SARS-CoV-2 infection and associated mortality across different variants of concern.

METHODS

A single-centre retrospective study of all nosocomial SARS-CoV-2 exposure events was conducted between 31^st December 2020 and 31^st December 2021. A secondary attack rate was calculated for nosocomial acquisition of SARS-CoV-2 infection and time to positivity. Positive contacts were assessed for all-cause 30-day mortality.

RESULTS

A total of 346 sequential index exposure events were examined, and 1378 susceptible contacts identified. Two hundred susceptible contacts developed SARS-CoV-2 infection (secondary attack rate of 15.5%). The majority of index cases (59%) did not result in any secondary SARS-CoV-2 infection. Where close contacts developed SARS-CoV-2 infection, 80% were detected within the first five days since last contact with the index case. The overall associated mortality among positive contacts across 2021 was 9%, with an estimated reduction of 68% when comparing periods of high Omicron versus Alpha transmission.

CONCLUSION

Our findings describe that most SARS-CoV-2 infections are detected within five days of contact with an index case; we have also demonstrated a considerably lower mortality rate with the Omicron variant in comparison to previous variants. These findings have important implications for informing and supporting infection control protocols to allow movement through the hospital, and ensure patients access care safely.

Multiple pathways of SARS-CoV-2 nosocomial transmission uncovered by integrated genomic and epidemiological analyses during the second wave of the COVID-19 pandemic in the UK

Introduction

Throughout the global COVID-19 pandemic, nosocomial transmission has represented a major concern for healthcare settings and has accounted for many infections diagnosed within hospitals. As restrictions ease and novel variants continue to spread, it is important to uncover the specific pathways by which nosocomial outbreaks occur to understand the most suitable transmission control strategies for the future.

Methods

In this investigation, SARS-CoV-2 genome sequences obtained from 694 healthcare workers and 1,181 patients were analyzed at a large acute NHS hospital in the UK between September 2020 and May 2021. These viral genomic data were combined with epidemiological data to uncover transmission routes within the hospital. We also investigated the effects of the introduction of the highly transmissible variant of concern (VOC), Alpha, over this period, as well as the effects of the national vaccination program on SARS-CoV-2 infection in the hospital.

Results

Our results show that infections of all variants within the hospital increased as community prevalence of Alpha increased, resulting in several outbreaks and super-spreader events. Nosocomial infections were enriched amongst older and more vulnerable patients more likely to be in hospital for longer periods but had no impact on disease severity. Infections appeared to be transmitted most regularly from patient to patient and from patients to HCWs. In contrast, infections from HCWs to patients appeared rare, highlighting the benefits of PPE in infection control. The introduction of the vaccine at this time also reduced infections amongst HCWs by over four-times.

Discussion

These analyses have highlighted the importance of control measures such as regular testing, rapid lateral flow testing alongside polymerase chain reaction (PCR) testing, isolation of positive patients in the emergency department (where possible), and physical distancing of patient beds on hospital wards to minimize nosocomial transmission of infectious diseases such as COVID-19.

Comparison of the healthcare-associated infections in intensive care units in Turkey before and during COVID-19

Background

Secondary bacterial infections are an important cause of mortality in patients with coronavirus disease 2019 (COVID-19). All healthcare providers acted with utmost care with the reflex of protecting themselves during the COVID-19 period. We aimed to compare the rates of ventilator-associated pneumonia (VAP) and bloodstream infections (BSIs) in our intensive care units (ICUs) before and during the COVID-19 outbreak surges.

Methods

This multicenter, retrospective, cross-sectional study was performed in six centers in Turkey. We collected the patient demographic characteristics, comorbidities, reasons for ICU admission, mortality and morbidity scores at ICU admission, and laboratory test data.

Results

A total of 558 patients who required intensive care from six centers were included in the study. Four hundred twenty-two of these patients (males (62%), whose mean age was 70 [IQR, 58-79] years) were followed up in the COVID period, and 136 (males (57%), whose mean age was 73 [IQR, 61-82] years) were followed up in the pre-COVID period. BSI and VAP rates were 20.7 (19 events in 916 patient days) and 17 (74 events in 4361 patient days) with a -3.8 difference (P = 0.463), and 33.7 (31 events in 919 patient days) and 34.6 (93 events in 2685 patient days) with a 0.9 difference (P = 0.897), respectively. The mortality rates were 71 (52%) in pre-COVID and 291 (69%) in COVID periods.

Conclusion

Protective measures that prioritize healthcare workers rather than patients and exceed standard measures made no difference in terms of reducing mortality.

Immunodeficient patient experience of emergency switch from intravenous to rapid push subcutaneous immunoglobulin replacement therapy during coronavirus disease 2019 shielding

PURPOSE OF REVIEW

Welsh immunodeficient patients on immunoglobulin replacement therapy (IgRT) who were considered high risk for severe coronavirus disease 2019 (COVID-19) were directed to shield. Consequently, patients receiving hospital-based intravenous immunoglobulin (IVIg) quickly transitioned to home-based self-administered subcutaneous immunoglobulin (SCIg). This evaluation aimed to assess patients' perceptions and experiences and laboratory outcomes of emergency IgRT transition during COVID-19.

RECENT FINDINGS

A quick transition from in-hospital IVIg to home-based rapid push SCIg is achievable, however, patient IgRT administration preference remains key outside of emergency shielding measures.

SUMMARY

Subjective self-reported experiences ( n  = 23) and objective immunoglobulin G (IgG) concentration ( n  = 28) assessments were prospectively collected from patients pre/post-IgRT switch. In total, 41/55 (75%) patients transitioned from IVIg to rapid push SCIg and all completed training to self-administer subcutaneously within 24 days. Twenty-two percent ( n  = 5) of patients preferred SCIg and 35% ( n  = 8) wanted to return to hospital-based IVIg at 6 weeks post-transition. Mean IgG levels were similar pre vs. post-SCIg switch (10.3 g/l vs. 10.6 g/l, respectively). Patients reported greater infection anxiety during COVID-19 and adapted behaviours to mitigate risk. Although a third of patients wished to return to IVIg following cessation of shielding, over time the percentage electing to remain on SCIg rose from 22% to 59%.

Strategies to promote guideline adoption: lessons learned from the implementation of a national COVID-19 hospital guideline across NHS Wales

There is little understanding about what proportion of the target audience have read guidelines published through the traditional approach. The COVID-19 pandemic created a particularly difficult scenario for healthcare professionals (HCP) since the evidence base rapidly changed. In response, we established a freely accessible, video-based online resource, which was formally implemented requiring user registration. The guideline rapidly gained more than 4,500 registrants in the first wave alone, including nearly 100% of respiratory, intensive care or emergency unit consultants in Wales. During the first wave, there were nearly 170,000 page views with over 31,000 video plays and an average of 5.8 visits to the site per registrant. Acceptability using an online survey showed widespread support and that the unsubscribe rates were remarkably low. We suggest that this novel approach to guideline implementation achieved its aim of widespread engagement and acceptability and serves as a potential model for future medical guidelines and education beyond COVID-19.

Charitably funded hospices and the challenges associated with the COVID-19 pandemic: a mixed-methods study (CovPall)

Background

Independent charitably funded hospices have been an important element of the UK healthcare response to the COVID-19 pandemic. Hospices usually have different funding streams, procurement processes, and governance arrangements compared to NHS provision, which may affect their experiences during the COVID-19 pandemic. The aim of this study is to understand the challenges faced by charitably funded hospices during the COVID-19 pandemic.

Methods

Eligible Organisations providing specialist palliative or hospice care completed the online CovPall survey (2020) which explored their response to the COVID-19 pandemic. Eligible organisations were then purposively selected to participate in interviews as part of qualitative case studies (2020-21) to understand challenges in more depth. Free-text responses from the survey were analysed using content analysis and were categorised accordingly. These categorisations were used a priori for a reflexive thematic analysis of interview data.

Results

143 UK independent charitably funded hospices completed the online CovPall survey. Five hospices subsequently participated in qualitative case studies (n = 24 staff interviews). Key themes include: vulnerabilities of funding; infection control during patient care; and bereavement support provision. Interviewees discussed the fragility of income due to fundraising events stopping; the difficulties of providing care to COVID-19 and non-COVID-19 patients within relatively small organisations; and challenges with maintaining the quality of bereavement services.

Conclusion

Some unique care and provision challenges during the COVID-19 pandemic were highlighted by charitably funded hospices. Funding core services charitably and independently may affect their ability to respond to pandemics, or scenarios where resources are unexpectedly insufficient.

Investigation of healthcare-associated COVID-19 in a large French hospital group by whole-genome sequencing

OBJECTIVES

Despite the quick implementation of infection prevention and control procedures and the use of personal protective equipment within healthcare facilities, many cases of nosocomial COVID-19 transmission have been reported. We aimed to estimate the frequency and impact of healthcare-associated COVID-19 (HA-COVID-19) and evaluate the contribution of whole-genome sequencing (WGS) in cluster investigation.

METHODS

We estimated the frequency and mortality of HA-COVID-19 infections from September 1 to November 30, 2020, with a focus on the evolution of hospitalized community-associated COVID-19 (CA-COVID-19) cases and cases detected among healthcare workers (HCWs) within the Sorbonne University Hospital Group (Paris, France). We thoroughly examined 12 clusters through epidemiological investigations and WGS.

RESULTS

Overall, 209 cases of HA-COVID-19 were reported. Evolution of HA-COVID-19 incidence closely correlated with the incidence of CA-COVID-19 and COVID-19 among HCWs. During the study period, 13.9 % of hospitalized patients with COVID-19 were infected in the hospital and the 30-day mortality rate of HA-COVID-19 was 31.5 %. Nosocomial transmission of SARS-CoV-2 led to clusters involving both patients and HCWs. WGS allowed the exclusion of one-third of cases initially assigned to a cluster.

CONCLUSIONS

WGS analysis combined with comprehensive epidemiological investigations is essential to understand transmission routes and adapt the IPC response to protect both patients and HCWs.

Healthcare-associated COVID-19 outbreaks: a nationwide population-based cohort study

Background

Aim

Methods

Findings

Conclusion

A Systematic Review and Meta-Analysis of Inpatient Mortality Associated With Nosocomial and Community COVID-19 Exposes the Vulnerability of Immunosuppressed Adults

Background

Little is known about the mortality of hospital-acquired (nosocomial) COVID-19 infection globally. We investigated the risk of mortality and critical care admission in hospitalised adults with nosocomial COVID-19, relative to adults requiring hospitalisation due to community-acquired infection.

Methods

We systematically reviewed the peer-reviewed and pre-print literature from 1/1/2020 to 9/2/2021 without language restriction for studies reporting outcomes of nosocomial and community-acquired COVID-19. We performed a random effects meta-analysis (MA) to estimate the 1) relative risk of death and 2) critical care admission, stratifying studies by patient cohort characteristics and nosocomial case definition.

Results

21 studies were included in the primary MA, describing 8,251 admissions across 8 countries during the first wave, comprising 1513 probable or definite nosocomial COVID-19, and 6738 community-acquired cases. Across all studies, the risk of mortality was 1.3 times greater in patients with nosocomial infection, compared to community-acquired (95% CI: 1.005 to 1.683). Rates of critical care admission were similar between groups (Relative Risk, RR=0.74, 95% CI: 0.50 to 1.08). Immunosuppressed patients diagnosed with nosocomial COVID-19 were twice as likely to die in hospital as those admitted with community-acquired infection (RR=2.14, 95% CI: 1.76 to 2.61).

Conclusions

Adults who acquire SARS-CoV-2 whilst already hospitalised are at greater risk of mortality compared to patients admitted following community-acquired infection; this finding is largely driven by a substantially increased risk of death in individuals with malignancy or who had undergone transplantation. These findings inform public health and infection control policy and argue for individualised clinical interventions to combat the threat of nosocomial COVID-19, particularly for immunosuppressed groups.

Systematic Review Registration

PROSPERO CRD42021249023.