Transmission of community- and hospital-acquired SARS-CoV-2 in hospital settings in the UK: A cohort study.

BACKGROUND: Nosocomial spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been widely reported, but the transmission pathways among patients and healthcare workers (HCWs) are unclear. Identifying the risk factors and drivers for these nosocomial transmissions is critical for infection prevention and control interventions. The main aim of our study was to quantify the relative importance of different transmission pathways of SARS-CoV-2 in the hospital setting. METHODS AND FINDINGS: This is an observational cohort study using data from 4 teaching hospitals in Oxfordshire, United Kingdom, from January to October 2020. Associations between infectious SARS-CoV-2 individuals and infection risk were quantified using logistic, generalised additive and linear mixed models. Cases were classified as community- or hospital-acquired using likely incubation periods of 3 to 7 days. Of 66,184 patients who were hospitalised during the study period, 920 had a positive SARS-CoV-2 PCR test within the same period (1.4%). The mean age was 67.9 (±20.7) years, 49.2% were females, and 68.5% were from the white ethnic group. Out of these, 571 patients had their first positive PCR tests while hospitalised (62.1%), and 97 of these occurred at least 7 days after admission (10.5%). Among the 5,596 HCWs, 615 (11.0%) tested positive during the study period using PCR or serological tests. The mean age was 39.5 (±11.1) years, 78.9% were females, and 49.8% were nurses. For susceptible patients, 1 day in the same ward with another patient with hospital-acquired SARS-CoV-2 was associated with an additional 7.5 infections per 1,000 susceptible patients (95% credible interval (CrI) 5.5 to 9.5/1,000 susceptible patients/day) per day. Exposure to an infectious patient with community-acquired Coronavirus Disease 2019 (COVID-19) or to an infectious HCW was associated with substantially lower infection risks (2.0/1,000 susceptible patients/day, 95% CrI 1.6 to 2.2). As for HCW infections, exposure to an infectious patient with hospital-acquired SARS-CoV-2 or to an infectious HCW were both associated with an additional 0.8 infection per 1,000 susceptible HCWs per day (95% CrI 0.3 to 1.6 and 0.6 to 1.0, respectively). Exposure to an infectious patient with community-acquired SARS-CoV-2 was associated with less than half this risk (0.2/1,000 susceptible HCWs/day, 95% CrI 0.2 to 0.2). These assumptions were tested in sensitivity analysis, which showed broadly similar results. The main limitations were that the symptom onset dates and HCW absence days were not available. CONCLUSIONS: In this study, we observed that exposure to patients with hospital-acquired SARS-CoV-2 is associated with a substantial infection risk to both HCWs and other hospitalised patients. Infection control measures to limit nosocomial transmission must be optimised to protect both staff and patients from SARS-CoV-2 infection.

Absence of COVID-19 Infection in Patients Accessing IBD Unit at Humanitas, Milan: Implications for Postlockdown Measures.

INTRODUCTION: The risk of coronavirus disease-19 infection for healthcare professionals and patients in hospitals remains unclear. METHODS: We investigated whether precautions adopted in our inflammatory bowel disease (IBD) unit have minimized the risks of infection for all patients accessing our facilities in a 1-month period by assessing the rate of coronavirus disease-19 infection in the follow-up period. RESULTS: Three hundred-twenty patients with IBD were included. None were infected from severe acute respiratory syndrome-coronavirus 2 in the follow-up period. None of the IBD team members were infected. DISCUSSION: Neither pharmacological immunosuppression nor access to the hospital seem to be risk factors for infection in patients with IBD.

Quantifying the relative impact of contact heterogeneity on MRSA transmission in ICUs - a modelling study.

BACKGROUND: An efficient surface cleaning strategy would first target cleaning to surfaces that make large contributions to the risk of infections. METHODS: In this study, we used data from the literature about methicillin-resistant Staphylococcus aureus (MRSA) and developed an ordinary differential equations based mathematical model to quantify the impact of contact heterogeneity on MRSA transmission in a hypothetical 6-bed intensive care unit (ICU). The susceptible patients are divided into two types, these who are cared by the same nurse as the MRSA infected patient (Type 1) and these who are not (Type 2). RESULTS: The results showed that the mean MRSA concentration on three kinds of susceptible patient nearby surfaces was significantly linearly associated with the hand-touch frequency (p < 0.05). The noncompliance of daily cleaning on patient nearby high-touch surfaces (HTSs) had the most impact on MRSA transmission. If the HTSs were not cleaned, the MRSA exposure to Type 1 and 2 susceptible patients would increase 118.4% (standard deviation (SD): 33.0%) and 115.4% (SD: 30.5%) respectively. The communal surfaces (CSs) had the least impact, if CSs were not cleaned, the MRSA exposure to Type 1 susceptible patient would only increase 1.7% (SD: 1.3). The impact of clinical equipment (CE) differed largely for two types of susceptible patients. If the CE was not cleaned, the exposure to Type 1 patients would only increase 8.4% (SD: 3.0%), while for Type 2 patients, it can increase 70.4% (SD: 25.4%). CONCLUSIONS: This study provided a framework to study the pathogen concentration dynamics on environmental surfaces and quantitatively showed the importance of cleaning patient nearby HTSs on controlling the nosocomial infection transmission via contact route.

Risk of SARS-CoV-2 transmission to medical staff and patients from an exposure to a COVID-19-positive ophthalmologist.

PURPOSE: To evaluate the risk of transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after exposure to a COVID-19+ physician in a retina clinic. METHODS: A retrospective observational study. Records of 142 patients and 11 staff members from a single retina clinic that were exposed to a COVID-19+ ophthalmologist were reviewed. All 153 individuals were placed in quarantine for 14 days. They were contacted after the quarantine period to inquire about symptoms consistent with COVID-19, and the results of diagnostic test for SARS-CoV-2 when performed. RESULTS: All patients (n = 142) were contacted successfully. The mean age was 72.8 ± 13.6 years; 54.2% (n = 77) were females. Twenty-three patients (16.2%) were exposed during an ophthalmic exam, 111 (78.2%) during intraocular injection, 4 (2.8%) underwent exam and injection, 3 (2.1%) underwent surgery, and one patient (0.7%) had laser photocoagulation. Half of the patients (50%; n = 71) were in contact with the COVID-19+ physician while he was symptomatic. Forty-four patients (31%) wore a mask on the day of their visit. 11.3% (n = 16) of the patients, and all involved staff had been tested for the virus and all were negative. One patient (0.7%) reported transient cough and sore throat, and the remaining 141 (99.3%) patients and 11 (100%) staff did not develop symptoms. CONCLUSIONS: Low risk for SARS-CoV-2 transmission in the ophthalmic setting was observed when universal safety measures such as social distancing, meticulous hand hygiene, enlarged breath shields, and mask wear during procedures were taken.

A cross-sectional study of immune seroconversion to SARS-CoV-2 in frontline maternity health professionals.

COVID-19, the respiratory disease caused by SARS-CoV-2, is thought to cause a milder illness in pregnancy with a greater proportion of asymptomatic carriers. This has important implications for the risk of patient-to-staff, staff-to-staff and staff-to-patient transmission among health professionals in maternity units. The aim of this study was to investigate the prevalence of previously undiagnosed SARS-CoV-2 infection in health professionals from two tertiary-level maternity units in London, UK, and to determine associations between healthcare workers' characteristics, reported symptoms and serological evidence of prior SARS-CoV-2 infection. In total, 200 anaesthetists, midwives and obstetricians, with no previously confirmed diagnosis of COVID-19, were tested for immune seroconversion using laboratory IgG assays. Comprehensive symptom and medical histories were also collected. Five out of 40 (12.5%; 95%CI 4.2-26.8%) anaesthetists, 7/52 (13.5%; 95%CI 5.6-25.8%) obstetricians and 17/108 (15.7%; 95%CI 9.5-24.0%) midwives were seropositive, with an overall total of 29/200 (14.5%; 95%CI 9.9-20.1%) of maternity healthcare workers testing positive for IgG antibodies against SARS-CoV-2. Of those who had seroconverted, 10/29 (35.5%) were completely asymptomatic. Fever or cough were only present in 6/29 (21%) and 10/29 (35%) respectively. Anosmia was the most common symptom occurring in 15/29 (52%) seropositive participants and was the only symptom that was predictive of positive seroconversion (OR 18; 95%CI 6-55). Of those who were seropositive, 59% had not self-isolated at any point and continued to provide patient care in the hospital setting. This is the largest study of baseline immune seroconversion in maternity healthcare workers conducted to date and reveals that one out of six were seropositive, of whom one out of three were asymptomatic. This has significant implications for the risk of occupational transmission of SARS-CoV-2 for both staff and patients in maternity units. Regular testing of staff, including asymptomatic staff should be considered to reduce transmission risk.

TB in healthcare workers in the UK: a cohort analysis 2009-2013.

OBJECTIVES: To describe the burden of TB in healthcare workers (HCWs) in the UK and determine whether HCWs are at increased risk of TB due to occupational exposure. METHODS: Retrospective cohort analysis of national UK TB surveillance and genotyping data between 2009 and 2013. The rate of TB in HCWs compared with non-HCWs to calculate incidence rate ratios stratified by country of birth. RESULTS: 2320 cases of TB in HCWs were notified in the study period, 85% were born abroad. The TB rate in HCWs was 23.4 (95% CI 22.5 to 24.4) per 100 000 compared with 16.2 (95% CI 16.0 to 16.3) per 100 000 in non-HCWs. After stratifying by country of birth, there was not an increased TB incidence in HCWs for the majority of countries of birth, including in the UK-born. Using combined genotyping and epidemiological data, only 10 confirmed nosocomial transmission events involving HCWs were identified between 2010 and 2012. Of these, only two involved transmission to patients. CONCLUSIONS: The lack of an increased risk of TB after stratifying by country of birth, and the very few transmission events involving nosocomial transmission in the UK suggests that TB in HCWs in the UK is not generally acquired through UK occupational exposure. The majority of cases in foreign-born HCWs are likely to result from reactivation of latent TB infection (LTBI) acquired abroad, and is not likely to be prevented by BCG vaccination in the UK. Testing and treatment of LTBI in HCWs with exposure to high TB burden countries should be the focus of occupational health prevention activities.

Management of occupational blood exposures: looking at progress.

Occupational blood exposure (OBE) is a well-recognised hazard in the healthcare setting. A 4-year review of OBE in a large Irish teaching hospital over 2008-2011 found encouraging results, but identified deficits in documentation, communication and follow-up. The process was repeated 1 year later to determine if improvements were achieved and recommendations implemented. In 2012, 110 OBEs were reported, of which 81% were reported within 72 hours of the injury. The administration of first aid was adequately documented in 85% of cases and confirmation of the provision of appropriate information and/or counselling in 72% of the cases. Attendance for follow-up was broadly in line with the previous review. The findings and recommendations contributed to improvements in practice. However, to ensure these are ongoing, the reinforcement of an educational strategy in a systematic way is fundamental.

Nosocomial transmission of respiratory syncytial virus in an outpatient cancer center.

Respiratory syncytial virus (RSV) outbreaks in inpatient settings are associated with poor outcomes in cancer patients. The use of molecular epidemiology to document RSV transmission in the outpatient setting has not been well described. We performed a retrospective cohort study of 2 nosocomial outbreaks of RSV at the Seattle Cancer Care Alliance. Subjects included patients seen at the Seattle Cancer Care Alliance with RSV detected in 2 outbreaks in 2007-2008 and 2012 and all employees with respiratory viruses detected in the 2007-2008 outbreak. A subset of samples was sequenced using semi-nested PCR targeting the RSV attachment glycoprotein coding region. Fifty-one cases of RSV were identified in 2007-2008. Clustering of identical viral strains was detected in 10 of 15 patients (67%) with RSV sequenced from 2007 to 2008. As part of a multimodal infection control strategy implemented as a response to the outbreak, symptomatic employees had nasal washes collected. Of 254 employee samples, 91 (34%) tested positive for a respiratory virus, including 14 with RSV. In another RSV outbreak in 2012, 24 cases of RSV were identified; 9 of 10 patients (90%) had the same viral strain, and 1 (10%) had another viral strain. We document spread of clonal strains within an outpatient cancer care setting. Infection control interventions should be implemented in outpatient, as well as inpatient, settings to reduce person-to-person transmission and limit progression of RSV outbreaks.

Nosocomial outbreak of staphyloccocal scalded skin syndrome in neonates in England, December 2012 to March 2013.

Staphylococcal scalded skin syndrome (SSSS) is a blistering skin condition caused by exfoliative toxin-producing strains of Staphylococcus aureus. Outbreaks of SSSS in maternity settings are rarely reported. We describe an outbreak of SSSS that occurred among neonates born at a maternity unit in England during December 2012 to March 2013. Detailed epidemiological and microbiological investigations were undertaken. Eight neonates were found to be infected with the outbreak strain of S. aureus, of spa type t346, representing a single pulsotype. All eight isolates contained genes encoding exfoliative toxin A (eta) and six of them contained genes encoding toxin B (etb). Nasal swabs taken during targeted staff screening yielded a staphylococcal carriage rate of 21% (17/80), but none contained the outbreak strain. Mass screening involving multi-site swabbing and pooled, enrichment culture identified a healthcare worker (HCW) with the outbreak strain. This HCW was known to have a chronic skin condition and their initial nasal screen was negative. The outbreak ended when they were excluded from work. This outbreak highlights the need for implementing robust swabbing and culture methodswhen conventional techniques are unsuccessful in identifying staff carrier(s). This study adds to the growing body of evidence on the role of HCWs in nosocomial transmission of S. aureus.

The dynamics of methicillin-resistant Staphylococcus aureus exposure in a hospital model and the potential for environmental intervention.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections. An important control strategy is hand hygiene; however, non-compliance has been a major problem in healthcare settings. Furthermore, modeling studies have suggested that the law of diminishing return applies to hand hygiene. Other additional control strategies such as environmental cleaning may be warranted, given that MRSA-positive individuals constantly shed contaminated desquamated skin particles to the environment. METHODS: We constructed and analyzed a deterministic environmental compartmental model of MRSA fate, transport, and exposure between two hypothetical hospital rooms: one with a colonized patient, shedding MRSA; another with an uncolonized patient, susceptible to exposure. Healthcare workers (HCWs), acting solely as vectors, spread MRSA from one patient room to the other. RESULTS: Although porous surfaces became highly contaminated, their low transfer efficiency limited the exposure dose to HCWs and the uncolonized patient. Conversely, the high transfer efficiency of nonporous surfaces allows greater MRSA transfer when touched. In the colonized patient's room, HCW exposure occurred more predominantly through the indirect (patient to surfaces to HCW) mode compared to the direct (patient to HCW) mode. In contrast, in the uncolonized patient's room, patient exposure was more predominant in the direct (HCW to patient) mode compared to the indirect (HCW to surfaces to patient) mode. Surface wiping decreased MRSA exposure to the uncolonized patient more than daily surface decontamination. This was because wiping allowed higher cleaning frequency and cleaned more total surface area per day. CONCLUSIONS: Environmental cleaning should be considered as an integral component of MRSA infection control in hospitals. Given the previously under-appreciated role of surface contamination in MRSA transmission, this intervention mode can contribute to an effective multiple barrier approach in concert with hand hygiene.

Methicillin-resistant staphylococcus aureus nasal colonization prevalence among Emergency Medical Services personnel.

INTRODUCTION: The prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization among Emergency Medical Services (EMS) personnel is not well studied. Methicillin-resistant Staphylococcus aureus colonization can be a health hazard for both EMS personnel and patients. The aim of this study was to quantify the prevalence of MRSA colonization among EMS personnel. This study will help the scientific community understand the extent of this condition so that further protocols and policies can be developed to support the health and wellbeing of EMS personnel. Hypothesis/ Problem The hypothesis of this study was that the prevalence of MRSA colonization among EMS personnel is significantly higher than among the general population. METHODS: This was a cross-sectional study. A total of 110 subjects were selected from two major US Mid-Atlantic fire departments. Methicillin-resistant Staphylococcus aureus colonization was detected by nasal swabbing. Nasal swabs were inoculated onto a special agar medium (C-MRSAgar) with polymerase chain reaction testing performed. One-sided binomial distribution at the Study Size 2.0 Web calculator was used. Using the Web calculator, p (H0 proportion) = 1.5%; a difference (H1-H0) 'Δ' = 4.53% can be detected at α = 5% and power = 80% with N = 110. RESULTS: Samples were collected from 110 volunteers. Seven samples were positive for MRSA, resulting in a prevalence of 7/110 or 6.4% (95% CI, 1.8%-11%; P < .0003) compared with a 1.5% prevalence of MRSA colonization among the general population. CONCLUSION: There is evidence that EMS personnel have a higher prevalence of MRSA colonization than the general population. This can be a risk to patients and can be recognized as an occupational hazard.

Quantifying transmission of norovirus during an outbreak.

BACKGROUND: Healthcare workers are thought to play a role in nosocomial transmission of norovirus, but the level and direction of norovirus transmission between patients and healthcare workers in sustaining transmission during an outbreak have not been quantified. METHODS: We developed a method for finding plausible transmission trees of who acquired their infection from whom. We applied the method to data from an outbreak of norovirus in 4 wards of a psychiatric institution in the Netherlands in 2008. The simulated transmission trees were based on serial intervals for time between symptom onsets, weighted for the number of days that healthcare workers were present. The obtained transmission trees were linked to the Barthel Index, a measure of patient reliance on healthcare in their basic daily activities. RESULTS: The dominant recognized transmission route was from patient to patient (64%), followed by patient to healthcare worker (29%). The overall estimated reproduction number for healthcare workers was low compared with patients (0.25 vs. 1.20; mean difference = 0.95 [95% confidence interval (CI) = 0.60 to 1.30]). The average number of all subsequent cases attributable to the downstream branch of one single infected healthcare worker in the transmission tree was 4.4 compared with 6.5 for cases attributable to one single infected patient (mean difference = 2.1 [95% CI = -4.7 to 8.9]). In the ward with patients requiring the highest level of care from healthcare workers, the attack rate among healthcare workers was highest. CONCLUSION: This approach provides a framework to quantify the magnitude and direction of transmission between healthcare workers and patients during a norovirus outbreak. The utility of this method in outbreaks of other infections and in different settings should be explored.

Burden and outcome of HIV infection and other morbidities in health care workers attending an Occupational Health Program at the Provincial Hospital of Tete, Mozambique.

OBJECTIVES: To investigate the burden and outcome of HIV infection and other morbidities amongst a Mozambican hospital staff. METHODS: Within an occupational health service set up in April 2008 in the provincial hospital of Tete, Mozambique, we offered to all staff members an initial clinical, laboratory and radiological screening and followed them up prospectively until April 2010. RESULTS: A total of 47.5% of 423 health workers attended the program. The cohort (female-to-male ratio: 2.2; mean age: 39 years) consisted mostly of auxiliary staff (43%) and nurses (29.8%). At initial screening, 71% were asymptomatic. HIV infection (28.4%) and tuberculosis (TB) (21%) were the main reported antecedent illnesses. Laboratory screening revealed anaemia (haemoglobin level <10 mg/dl) in 9% participants, abnormal liver enzymes in 23.9% and a reactive non-treponemal syphilis test in 5%. Of 145 performed chest X-rays, 13% showed abnormalities. All 113 health workers not recently tested for HIV were screened, and 31 were newly diagnosed with HIV infection (resulting in an overall HIV prevalence of 43.8%). Nine cases of TB were diagnosed at screening/during follow-up. In April 2010, all but one of the participants were alive. All HIV-infected health workers under antiretroviral therapy were actively followed-up. CONCLUSION: Serious conditions were frequently diagnosed in health workers, in particular HIV infection. Mid-term outcome was favourable within this program. Creation of screening and care services dedicated to caregivers should be of highest priority in similar African settings.

[Clinical features and contagiousness of influenza A(H1N1) in health care workers and hospitalized patients in a Mexico City hospital]. / Características y contagiosidad de influenza A(H1N1) y estacional en trabajadores sanitarios y pacientes de un hospital en la ciudad de México.

INTRODUCTION: Respiratory infections increased in Mexico in 2009 due to an epidemic of influenza. METHODS: To compare symptoms and infectivity of influenza A(H1N1) and seasonal influenza we evaluated epidemiological data and microbiological sampling of health workers (HW) and patients who probably had influenza. RESULTS: From April to November 2009 we studied 83 HW (29 with influenza A(H1N1) and 8 with seasonal influenza) and 71 patients (26 and 11, respectively). The subtypes of influenza had similar clinical data. CONCLUSIONS: Fifteen patients with immunosuppression or chronic diseases developed fatal pneumonia; the infectivity was greater for influenza A(H1N1).

Nosocomial Respiratory Infections in a Rural Zambian Hospital.

The burden of nosocomial respiratory infections in rural southern Africa is poorly understood. We established a surveillance program at a rural Zambian hospital to detect influenza-like illness (ILI) and respiratory infections among hospitalized patients and a cohort of healthcare workers (HCWs). Nasopharyngeal specimens from symptomatic patients and HCWs underwent broadly multiplexed molecular testing to detect viruses and atypical bacteria. During 1 year of surveillance, 15 patients (1.7% of admissions) developed ILI more than 48 hours after admission. Among 44 HCWs, 19 (43%) experienced at least one ILI episode, with a total of 31 ILI episodes detected. Respiratory viruses were detected in 45% of patient and 55% of HCW specimens. The cumulative incidence of influenza infection among HCWs over 1 year was 9%. Overall, respiratory viruses were commonly found among patients and HCWs in a rural Zambian hospital with limited infection control infrastructure.

Neonatal staphylococcal scalded skin syndrome: clinical and outbreak containment review.

Staphylococcal scalded skin syndrome (SSSS) is a toxin-mediated exfoliating skin condition predominated by desquamation and blistering. Neonatal outbreaks have already been reported; however, our outbreak highlights the potential for SSSS following neonatal health promotion measures such as intra-muscular vitamin K administration and metabolic screening (heel prick) as well as effective case containment measures and the value of staff screening. Between February and June 2007, five confirmed cases of neonatal SSSS were identified in full-term neonates born in an Irish regional maternity hospital. All infants were treated successfully. Analysis of contact and environmental screening was undertaken, including family members and healthcare workers. Molecular typing on isolates was carried out. An outbreak control team (OCT) was assembled and took successful prospective steps to prevent further cases. All five Staphylococcus aureus isolates tested positive for exfoliative toxin A, of which two distinct strains were identified on pulsed-field gel electrophoresis analysis. Two cases followed staphylococcal inoculation during preventive measures such as intra-muscular vitamin K administration and metabolic screening (heel prick). None of the neonatal isolates were methicillin resistant. Of 259 hospital staff (70% of staff) screened, 30% were colonised with S. aureus, and 6% were positive for MRSA carriage. This is the first reported outbreak of neonatal SSSS in Ireland. Effective case containment measures and clinical value of OCT is demonstrated. Results of staff screening underlines the need for vigilance and compliance in hand disinfection strategies in maternity hospitals especially during neonatal screening and preventive procedures.

Extended-spectrum beta-lactamases Klebsiella pneumoniae: multimodal infection control program in intensive care units.

INTRODUCTION: The aims of our study were to investigate a nosocomial spread of an extended-spectrum fl-lactamases-Klebsiella pneumoniae cluster at a University teaching hospital in Italy, to describe, and to monitor the implementation of a multimodal infection control program in two mixed ICUs. METHODS: During the 1 October 2005-30 September 2006 period, 79 colonized patients have been identified. Isolates were genotyped by pulsed-field gel electrophoresis (PFGE). A mutimodal infection control program with monitoring of alcohol-based hand rub was performed in Intensive Care Units (ICU A and ICU B). RESULTS: The epidemiological investigation and PFGE showed a horizontal transmission of the same PFGE genotype, with the isolation of the outbreak strain on the hand of one healthcare operator. Alcohol based hand rub was adopted in ICUA on 18 March 2006, in addition to hand washing with plain or antiseptic soap. ICU B did not change its hand hygiene habits. Following the implementation of the program, the incidence density rate (IDR) in ICU A fell down from 4.50 to 1.68/1000 patient days. DISCUSSION AND CONCLUSIONS: Our findings confirm the important role of personnel in cross-transmission. Moreover the inbuilt control group involuntarily offered by the delaying of the intervention in ICU B has given the opportunity to verify the epidemiological association between the actual implementation of infection control practices and the outbreak control.