Predicting consequences of COVID-19 control measure de-escalation on nosocomial transmission and mortality: a modelling study in a French rehabilitation hospital.

INTRODUCTION: Infection control measures are effective for nosocomial COVID-19 prevention but bear substantial health-economic costs, motivating their "de-escalation" in settings at low risk of SARS-CoV-2 transmission. Yet consequences of de-escalation are difficult to predict, particularly in light of novel variants and heterogeneous population immunity. AIM: To estimate how infection control measure de-escalation influences nosocomial COVID-19 risk. METHODS: An individual-based transmission model was used to simulate SARS-CoV-2 outbreaks and control measure de-escalation in a French long-term care hospital with multi-modal control measures in place (testing and isolation, universal masking, single-occupant rooms). Estimates of COVID-19 case fatality rates (CFRs) from reported outbreaks were used to quantify excess COVID-19 mortality due to de-escalation. RESULTS: In a population fully susceptible to infection, de-escalating both universal masking and single rooms resulted in hospital-wide outbreaks of 114 (95% CI: 103-125) excess infections, compared with five (three to seven) excess infections when de-escalating only universal masking or 15 (11-18) when de-escalating only single rooms. When de-escalating both measures and applying CFRs from the first wave of COVID-19, excess patient mortality ranged from 1.57 (1.41-1.71) to 9.66 (8.73-10.57) excess deaths/1000 patient-days. By contrast, when applying CFRs from subsequent pandemic waves and assuming susceptibility to infection among 40-60% of individuals, excess mortality ranged from 0 (0-0) to 0.92 (0.77-1.07) excess deaths/1000 patient-days. CONCLUSIONS: The de-escalation of bundled COVID-19 control measures may facilitate widespread nosocomial SARS-CoV-2 transmission. However, excess mortality is probably limited in populations at least moderately immune to infection and given CFRs resembling those estimated during the 'post-vaccine' era.

How have mathematical models contributed to understanding the transmission and control of SARS-CoV-2 in healthcare settings? A systematic search and review.

Since the onset of the COVID-19 pandemic, mathematical models have been widely used to inform public health recommendations regarding COVID-19 control in healthcare settings. The objective of this study was to systematically review SARS-CoV-2 transmission models in healthcare settings, and to summarize their contributions to understanding nosocomial COVID-19. A systematic search and review of published articles indexed in PubMed was carried out. Modelling studies describing dynamic inter-individual transmission of SARS-CoV-2 in healthcare settings, published by mid-February 2022 were included. Models have mostly focused on acute-care and long-term-care facilities in high-income countries. Models have quantified outbreak risk, showing great variation across settings and pandemic periods. Regarding surveillance, routine testing rather than symptom-based was highlighted as essential for COVID-19 prevention due to high rates of silent transmission. Surveillance impacts depended critically on testing frequency, diagnostic sensitivity, and turn-around time. Healthcare re-organization also proved to have large epidemiological impacts: beyond obvious benefits of isolating cases and limiting inter-individual contact, more complex strategies (staggered staff scheduling, immune-based cohorting) reduced infection risk. Finally, vaccination impact, while highly effective for limiting COVID-19 burden, varied substantially depending on assumed mechanistic impacts on infection acquisition, symptom onset and transmission. Modelling results form an extensive evidence base that may inform control strategies for future waves of SARS-CoV-2 and other viral respiratory pathogens. We propose new avenues for future models of healthcare-associated outbreaks, with the aim of enhancing their efficiency and contributions to decision-making.

Seasonality of urinary tract infections in the United Kingdom in different age groups: longitudinal analysis of The Health Improvement Network (THIN).

Evidence regarding the seasonality of urinary tract infection (UTI) consultations in primary care is conflicting and methodologically poor. To our knowledge, this is the first study to determine whether this seasonality exists in the UK, identify the peak months and describe seasonality by age. The monthly number of UTI consultations (N = 992 803) and nitrofurantoin and trimethoprim prescriptions (N = 1 719 416) during 2008-2015 was extracted from The Health Improvement Network (THIN), a large nationally representative UK dataset of electronic patient records. Negative binomial regression models were fitted to these data to investigate seasonal fluctuations by age group (14-17, 18-24, 25-45, 46-69, 70-84, 85+) and by sex, accounting for a change in the rate of UTI over the study period. A September to November peak in UTI consultation incidence was observed for ages 14-69. This seasonality progressively faded in older age groups and no seasonality was found in individuals aged 85+, in whom UTIs were most common. UTIs were rare in males but followed a similar seasonal pattern than in females. We show strong evidence of an autumnal seasonality for UTIs in individuals under 70 years of age and a lack of seasonality in the very old. These findings should provide helpful information when interpreting surveillance reports and the results of interventions against UTI.

[Characteristics of the population hospitalized for advanced and terminal heart failure and experiences in palliative caring in the Intensive Care Unit of cardiology]. / Caractéristiques et prise en charge des patients hospitalisés pour insuffisance cardiaque terminale ayant fait l'objet d'une limitation de soins en unité de soins intensifs cardiologiques.

PURPOSE: Advanced heart failure incidence is in progression. Palliative care access remains difficult due to its unpredictable course. The aim of this study was to describe the characteristics of patients admitted in Cardiology Intensive Care Unit for advanced heart failure who received palliative care and compare them to the whole population of acute heart failure hospitalized in the same period. PATIENTS AND METHODS: The patients hospitalized for acute heart failure were retrospectively included from 2009 to 2013. We identified among them those who received palliative care. Specific caring was decided in pluridisciplinary meeting. RESULTS: On 940 patients included, 42 patients (4.5%) receive palliative care. Ischemic heart disease was the main etiology (n=19; 45.2%). Right ventricular dysfunction (n=34; 80.9%) was associated with supra-ventricular arrhythmia (n=28; 66.7%). Twenty-eight patients (57.1%) have died in hospital, 9 (21.4%) were referred to a palliative care unit and 8 (19.1%) was discharged or referred to a rehabilitation center. Time between inclusion and death was 6 days on average. Intra-hospital mortality in control group was 6.8%. CONCLUSION: Palliative care in cardiology is uncommon and has often been too late because of its poor adaptability to advanced heart failure. It is, as consequence, necessary to identify the prognostic factors of these patients in order to propose a personalized care and to adjust the intensity of care ahead of the terminal evolution of heart failure.

Studies on guinea pig skin cell cultures. VI. Growth kinetics of epidermal keratinocytes and dermal fibroblasts.

The growth kinetics of epidermal keratinocytes (EK) and dermal fibroblasts (DF) have been determined by four different methods: incorporation of 3H-thymidine into DNA (3H-microgram DNA ratio); 3H-thymidine/14C amino acid incorporation ratio (3H:14C ratio); 3H-thymidine labelled nuclei, and colchicine-blocked metaphase counts. The growth curve of EK was no different when plotted with the 3H:14C ratio than with the 3H-microgram DNA ratio. However, this was not true for DF. The replacement of sodium bicarbonate with Hepes buffer in the culture medium did not greatly affect the shape of the EK growth curve, whereas the DF growth curve became diphasic instead of monophasic. The elimination of mature (differentiated) keratinocytes from the very onset of EK culture had a profound effect on the EK growth curve. DNA synthesis peaked at day 1 in cultures without, instead of day 9 in cultures with differentiated cells. Furthermore, mitotic activity did not show up before day 6. This suggests that (i) EK in culture are sensitive to the G1 inhibitor released by differentiated epidermal cells, and (ii) they remain in G2 for about 5 days. Thus, EK in culture seem to continue to be susceptible, as in vivo, to homeostatic regulation through the action of G1-G2 inhibitors.