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.

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.

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.

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.

COVID-19 emergency response assessment study: a prospective longitudinal survey of frontline doctors in the UK and Ireland: study protocol.

INTRODUCTION: The COVID-19 pandemic is putting an unprecedented strain on healthcare systems globally. The psychological impact on frontline doctors of dealing with the COVID-19 pandemic is currently unknown. This longitudinal professional survey aims to understand the evolving and cumulative effects of working during the COVID-19 outbreak on the psychological well-being of doctors working in emergency departments (ED), intensive care units (ICU) and anaesthetics during the pandemic. METHODS AND ANALYSIS: This study is a longitudinal questionnaire-based study with three predefined time points spanning the acceleration, peak and deceleration phases of the COVID-19 pandemic.The primary outcomes are psychological distress and post-trauma stress as measured by the General Health Questionnaire-12 (GHQ-12) and Impact of Events Scale-Revised (IES-R). Data related to personal and professional characteristics will also be collected. Questionnaires will be administered prospectively to all doctors working in ED, ICU and anaesthetics in the UK and Ireland via existing research networks during the sampling period. Data from the questionnaires will be analysed to assess the prevalence and degree of psychological distress and trauma, and the nature of the relationship between personal and professional characteristics and the primary outcomes. Data will be described, analysed and disseminated at each time point; however, the primary endpoint will be psychological distress and trauma at the final time point. ETHICS AND DISSEMINATION: Ethical approval was obtained from the University of Bath, UK (ref: 4421), and Children's Health Ireland at Crumlin, Ethics Committee. Regulatory approval from the Health Regulation Authority (UK), Health and Care Research Wales (IRAS: 281944).This study is limited by the fact that it focuses on doctors only and is survey based without further qualitative interviews of participants. It is expected this study will provide clear evidence of the psychological impact of COVID-19 on doctors and will allow present and future planning to mitigate against any psychological impact. TRIAL REGISTRATION NUMBER: ISRCTN10666798.

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.

What proportion of healthcare worker masks carry virus? A systematic review.

OBJECTIVE: Concerns have been raised by healthcare organisations in New Zealand that routine mask use by healthcare workers (HCW) may increase the risk of transmission of SARS-CoV-2 through increased face touching. Routine mask use by frontline HCW was not recommended when seeing 'low risk' patients. The aim of this review was to determine the carriage of respiratory viruses on facemasks used by HCW. METHODS: A systematic review was conducted with structured searches of medical and allied health databases. Two authors independently screened articles for inclusion, with substantial agreement (k = 0.66, 95% CI 0.54-0.79). Studies that at least one author recommended for full text review were reviewed in full for inclusion. Two authors independently extracted data from included studies including the setting, method of analysis and results. There was exact agreement on the proportion of virus detected on masks. RESULTS: We retrieved 1233 titles, 47 underwent full text review and five studies reported in four articles were included. The studies were limited by small numbers and failure to test all eligible masks in some studies. The proportion in each study ranged from 0 (95% CI 0-10) to 25% (95% CI 8-54). No study reported clinical respiratory illness as a result of virus on the masks. CONCLUSIONS: Although limited, current evidence suggests that viral carriage on the outer surface of surgical masks worn by HCW treating patients with clinical respiratory illness is low and there was not strong evidence to support the assumption that mask use may increase the risk of viral transmission.

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.

[The role of hospital environment and the hands of medical staff in the transmission of the Clostridioides (Clostridium) difficile infection]. / Rola srodowiska szpitalnego i rak personelu medycznego w szerzeniu sie zakazen Clostridioides (Clostridium) difficile.

This paper attempts to determine the role of the hospital environment in the spread of Clostridioides/Clostridium (C.) difficile infections based on a review of studies published in the medical literature and in the light of the authors' own experiences. Clostridioides/Clostridium difficile has recently attracted more and more attention, not only as an etiological factor of pseudomembranous intestinal inflammation and antibiotic associated diarrhea, but also as an etiologic factor of healthcare-associated infections (HAI) because of the possibility to survive in the hospital environment for a long time. This is caused by the production of spores, whose eradication options are limited. Clostridioides/Clostridium difficile spores are present not only on bedding of infected patients and their other belongings, but also on medical equipment and the hands of medical personnel, constituting a potential source of infection for other patients and some of the staff. The introduction of appropriate procedures for hand hygiene as well as for cleaning and disinfection of hospital surfaces makes it possible to reduce the number of spores and/or eradicate them. These procedures must be strictly followed to reduce the occurrence of spores in the hospital environment and to prevent further spread of C. difficile infections (CDI). Monitoring the presence of the C. difficile spores in a hospital environment using appropriate media (C diff Banana BrothTM) provides additional opportunities for culturing of C. difficile strains and determining ribotypes, especially hyperepidemic ones, which is extremely important from an epidemiological point of view. Med Pr. 2019;70(6):739-45.

Comparative Analysis of Eleven Healthcare-Associated Outbreaks of Middle East Respiratory Syndrome Coronavirus (Mers-Cov) from 2015 to 2017.

Since its emergence in 2012, 2,260 cases and 803 deaths due to Middle East respiratory syndrome coronavirus (MERS-CoV) have been reported to the World Health Organization. Most cases were due to transmission in healthcare settings, sometimes causing large outbreaks. We analyzed epidemiologic and clinical data of laboratory-confirmed MERS-CoV cases from eleven healthcare-associated outbreaks in the Kingdom of Saudi Arabia and the Republic of Korea between 2015-2017. We quantified key epidemiological differences between outbreaks. Twenty-five percent (n = 105/422) of MERS cases who acquired infection in a hospital setting were healthcare personnel. In multivariate analyses, age ≥65 (OR 4.8, 95%CI: 2.6-8.7) and the presence of underlying comorbidities (OR: 2.7, 95% CI: 1.3-5.7) were associated with increased mortality whereas working as healthcare personnel was protective (OR 0.07, 95% CI: 0.01-0.34). At the start of these outbreaks, the reproduction number ranged from 1.0 to 5.7; it dropped below 1 within 2 to 6 weeks. This study provides a comprehensive characterization of MERS HCA-outbreaks. Our results highlight heterogeneities in the epidemiological profile of healthcare-associated outbreaks. The limitations of our study stress the urgent need for standardized data collection for high-threat respiratory pathogens, such as MERS-CoV.

Transfer of pathogens to and from patients, healthcare providers, and medical devices during care activity-a systematic review and meta-analysis.

OBJECTIVE: The transfer of pathogens may spread antimicrobial resistance and lead to healthcare-acquired infections. We performed a systematic literature review to generate estimates of pathogen transfer in relation to healthcare provider (HCP) activities. METHODS: For this systematic review and meta-analysis, Medline/Ovid, EMBASE, and the Cochrane Library were searched for studies published before July 7, 2017. We reviewed the literature, examining transfer of pathogens associated with HCP activities. We included studies that (1) quantified transfer of pathogens from a defined origin to a defined destination surface; (2) reported a microbiological sampling technique; and (3) described the associated activity leading to transfer. For studies reporting transfer frequencies, we extracted data and calculated the estimated proportion using Freeman-Tukey double arcsine transformation and the DerSimonian-Laird random-effects model. RESULTS: Of 13,121 identified articles, 32 were included. Most articles (n=27, 84%) examined transfer from patients and their environment to HCP hands, gloves, and gowns, with an estimated proportion for transfer frequency of 33% (95% confidence interval [CI], 12%-57%), 30% (95% CI, 23%-38%) and 10% (95% CI, 6%-14%), respectively. Other articles addressed transfer involving the hospital environment and medical devices. Risk factor analyses in 12 studies suggested higher transfer frequencies after contact with moist body sites (n=7), longer duration of care (n=5), and care of patients with an invasive device (n=3). CONCLUSIONS: Recognizing the heterogeneity in study designs, the available evidence suggests that pathogen transfer to HCPs occurs frequently. More systematic research is urgently warranted to support targeted and economic prevention policies and interventions.

A systematic review and meta-analysis of the direct epidemiological and economic effects of seasonal influenza vaccination on healthcare workers.

BACKGROUND: Influenza vaccination is a commonly used intervention to prevent influenza infection in healthcare workers (HCWs) and onward transmission to other staff and patients. We undertook a systematic review to synthesize the latest evidence of the direct epidemiological and economic effectiveness of seasonal influenza vaccination among HCW. METHODS: We conducted a systematic search of MEDLINE/PubMed, Scopus, and Cochrane Central Register of Controlled Trials from 1980 through January 2018. All studies comparing vaccinated and non-vaccinated (i.e. placebo or non-intervention) groups of HCWs were included. Research articles that focused on only patient-related outcomes or monovalent A(H1N1)pdm09 vaccines were excluded. Two reviewers independently selected articles and extracted data. Pooled-analyses were conducted on morbidity outcomes including laboratory-confirmed influenza, influenza-like illnesses (ILI), and absenteeism. Economic studies were summarized for the characteristics of methods and findings. RESULTS: Thirteen articles met eligibility criteria: three articles were randomized controlled studies and ten were cohort studies. Pooled results showed a significant effect on laboratory-confirmed influenza incidence but not ILI. While the overall incidence of absenteeism was not changed by vaccine, ILI absenteeism was significantly reduced. The duration of absenteeism was also shortened by vaccination. All published economic evaluations consistently found that the immunization of HCW was cost saving based on crude estimates of avoided absenteeism by vaccination. No studies, however, comprehensively evaluated both health outcomes and costs of vaccination programs to examine cost-effectiveness. DISCUSSION: Our findings reinforced the influenza vaccine effects in reducing infection incidence and length of absenteeism. A better understanding of the incidence of absenteeism and comprehensive economic program evaluations are required to ensure the best possible management of ill HCWs and the investment in HCW immunization in increasingly constrained financial environments. These steps are fundamental to establish sustainability and cost-effectiveness of vaccination programs and underpin HCW immunization policy.

The Risk of Cross Infection in the Emergency Department: A Simulation Study.

OBJECTIVESThe risk of cross infection in a busy emergency department (ED) is a serious public health concern, especially in times of pandemic threats. We simulated cross infections due to respiratory diseases spread by large droplets using empirical data on contacts (ie, close-proximity interactions of ≤1m) in an ED to quantify risks due to contact and to examine factors with differential risks associated with them.DESIGNProspective study.PARTICIPANTSHealth workers (HCWs) and patients.SETTINGA busy ED.METHODSData on contacts between participants were collected over 6 months by observing two 12-hour shifts per week using a radiofrequency identification proximity detection system. We simulated cross infection due to a novel agent across these contacts to determine risks associated with HCW role, chief complaint category, arrival mode, and ED disposition status.RESULTSCross-infection risk between HCWs was substantially greater than between patients or between patients and HCWs. Providers had the least risk, followed by nurses, and nonpatient care staff had the most risk. There were no differences by patient chief complaint category. We detected differential risk patterns by arrival mode and by HCW role. Although no differential risk was associated with ED disposition status, 0.1 infections were expected per shift among patients admitted to hospital.CONCLUSIONThese simulations demonstrate that, on average, 11 patients who were infected in the ED will be admitted to the hospital over the course of an 8-week local influenza outbreak. These patients are a source of further cross-infection risk once in the hospital.Infect Control Hosp Epidemiol 2018;39:688-693.

Prevalence and risk factors for latent tuberculosis infection among primary health care workers in Brazil.

Health care workers (HCW) are at increased risk of latent tuberculosis infection (LTBI) from occupational exposure to Mycobacterium tuberculosis. The objective was to determine the prevalence of and risk factors for LTBI among primary HCW in five Brazilian cities. We conducted a cross-sectional study, from 2011 to 2013, among primary HCW, using a structured questionnaire and an evaluated for LTBI using the Quantiferon-TB Gold in-tube test. The magnitude of the associations was assessed using hierarchical logistic regression models. Among 708 HCW, the LTBI prevalence was 27% (n = 196; 95%CI: 24%-31%). We found that the following factors were positively associated with LTBI in primary HCW: age > 50 years (OR = 2.94; 95%CI: 1.44-5.99), absence of a BCG scar (OR = 2.10; 95%CI: 1.28-3.43), self-reported ex-smoker status (OR = 1.80; 95%CI: 1.04-3.11), being a nurse (OR = 2.97; 95%CI: 1.13-7.83), being a nurse technician (OR = 3.10; 95%CI: 1.26-7.60), being a community health agent (OR = 2.60; 95%CI: 1.06-6.40), and irregular use of N95 masks (OR = 2.51; 95%CI: 1.11-5.98). In contrast, HCWs who do not work in health care facilities with a TB control program were less likely to have LTBI (OR = 0.66; 95%CI: 0.45-0.97). This study demonstrated a substantial occupational risk of LTBI among primary HCW in Brazil. The Brazilian TB control program, as well as local programs, need to target these high-risk HCW with education, as well as with better personal protective equipment to prevent acquisition of new TB infection.

Provider Role in Transmission of Carbapenem-Resistant Enterobacteriaceae.

OBJECTIVE We sought to evaluate the role healthcare providers play in carbapenem-resistant Enterobacteriaceae (CRE) acquisition among hospitalized patients. DESIGN A 1:4 case-control study with incidence density sampling. SETTING Academic healthcare center with regular CRE perirectal screening in high-risk units. PATIENTS We included case patients with ≥1 negative CRE test followed by positive culture with a length of stay (LOS) >9 days. For controls, we included patients with ≥2 negative CRE tests and assignment to the same unit set as case patients with a LOS >9 days. METHODS Controls were time-matched to each case patient. Case exposure was evaluated between days 2 and 9 before positive culture and control evaluation was based on maximizing overlap with the case window. Exposure sources were all CRE-colonized or -infected patients. Nonphysician providers were compared between study patients and sources during their evaluation windows. Dichotomous and continuous exposures were developed from the number of source-shared providers and were used in univariate and multivariate regression. RESULTS In total, 121 cases and 484 controls were included. Multivariate analysis showed odds of dichotomous exposure (≥1 source-shared provider) of 2.27 (95% confidence interval [CI], 1.25-4.15; P=.006) for case patients compared to controls. Multivariate continuous exposure showed odds of 1.02 (95% CI, 1.01-1.03; P=.009) for case patients compared to controls. CONCLUSIONS Patients who acquire CRE during hospitalization are more likely to receive care from a provider caring for a patient with CRE than those patients who do not acquire CRE. These data support the importance of hand hygiene and cohorting measures for CRE patients to reduce transmission risk. Infect Control Hosp Epidemiol 2017;38:1329-1334.

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.