Ambient carbon dioxide concentration correlates with SARS-CoV-2 aerostability and infection risk.

An improved understanding of the underlying physicochemical properties of respiratory aerosol that influence viral infectivity may open new avenues to mitigate the transmission of respiratory diseases such as COVID-19. Previous studies have shown that an increase in the pH of respiratory aerosols following generation due to changes in the gas-particle partitioning of pH buffering bicarbonate ions and carbon dioxide is a significant factor in reducing SARS-CoV-2 infectivity. We show here that a significant increase in SARS-CoV-2 aerostability results from a moderate increase in the atmospheric carbon dioxide concentration (e.g. 800 ppm), an effect that is more marked than that observed for changes in relative humidity. We model the likelihood of COVID-19 transmission on the ambient concentration of CO2, concluding that even this moderate increase in CO2 concentration results in a significant increase in overall risk. These observations confirm the critical importance of ventilation and maintaining low CO2 concentrations in indoor environments for mitigating disease transmission. Moreover, the correlation of increased CO2 concentration with viral aerostability need to be better understood when considering the consequences of increases in ambient CO2 levels in our atmosphere.

SARS-CoV-2 variant of concern fitness and adaptation in primary human airway epithelia.

The severe acute respiratory syndrome coronavirus 2 pandemic is characterized by the emergence of novel variants of concern (VOCs) that replace ancestral strains. Here, we dissect the complex selective pressures by evaluating variant fitness and adaptation in human respiratory tissues. We evaluate viral properties and host responses to reconstruct forces behind D614G through Omicron (BA.1) emergence. We observe differential replication in airway epithelia, differences in cellular tropism, and virus-induced cytotoxicity. D614G accumulates the most mutations after infection, supporting zoonosis and adaptation to the human airway. We perform head-to-head competitions and observe the highest fitness for Gamma and Delta. Under these conditions, RNA recombination favors variants encoding the B.1.617.1 lineage 3' end. Based on viral growth kinetics, Alpha, Gamma, and Delta exhibit increased fitness compared to D614G. In contrast, the global success of Omicron likely derives from increased transmission and antigenic variation. Our data provide molecular evidence to support epidemiological observations of VOC emergence.

Lineage frequency time series reveal elevated levels of genetic drift in SARS-CoV-2 transmission in England.

Genetic drift in infectious disease transmission results from randomness of transmission and host recovery or death. The strength of genetic drift for SARS-CoV-2 transmission is expected to be high due to high levels of superspreading, and this is expected to substantially impact disease epidemiology and evolution. However, we don't yet have an understanding of how genetic drift changes over time or across locations. Furthermore, noise that results from data collection can potentially confound estimates of genetic drift. To address this challenge, we develop and validate a method to jointly infer genetic drift and measurement noise from time-series lineage frequency data. Our method is highly scalable to increasingly large genomic datasets, which overcomes a limitation in commonly used phylogenetic methods. We apply this method to over 490,000 SARS-CoV-2 genomic sequences from England collected between March 2020 and December 2021 by the COVID-19 Genomics UK (COG-UK) consortium and separately infer the strength of genetic drift for pre-B.1.177, B.1.177, Alpha, and Delta. We find that even after correcting for measurement noise, the strength of genetic drift is consistently, throughout time, higher than that expected from the observed number of COVID-19 positive individuals in England by 1 to 3 orders of magnitude, which cannot be explained by literature values of superspreading. Our estimates of genetic drift suggest low and time-varying establishment probabilities for new mutations, inform the parametrization of SARS-CoV-2 evolutionary models, and motivate future studies of the potential mechanisms for increased stochasticity in this system.

SARS-CoV-2 Viral Shedding and Rapid Antigen Test Performance - Respiratory Virus Transmission Network, November 2022-May 2023.

As population immunity to SARS-CoV-2 evolves and new variants emerge, the role and accuracy of antigen tests remain active questions. To describe recent test performance, the detection of SARS-CoV-2 by antigen testing was compared with that by reverse transcription-polymerase chain reaction (RT-PCR) and viral culture testing during November 2022-May 2023. Participants who were enrolled in a household transmission study completed daily symptom diaries and collected two nasal swabs (tested for SARS-CoV-2 via RT-PCR, culture, and antigen tests) each day for 10 days after enrollment. Among participants with SARS-CoV-2 infection, the percentages of positive antigen, RT-PCR, and culture results were calculated each day from the onset of symptoms or, in asymptomatic persons, from the date of the first positive test result. Antigen test sensitivity was calculated using RT-PCR and viral culture as references. The peak percentage of positive antigen (59.0%) and RT-PCR (83.0%) results occurred 3 days after onset, and the peak percentage of positive culture results (52%) occurred 2 days after onset. The sensitivity of antigen tests was 47% (95% CI = 44%-50%) and 80% (95% CI = 76%-85%) using RT-PCR and culture, respectively, as references. Clinicians should be aware of the lower sensitivity of antigen testing compared with RT-PCR, which might lead to false-negative results. This finding has implications for timely initiation of SARS-CoV-2 antiviral treatment, when early diagnosis is essential; clinicians should consider RT-PCR for persons for whom antiviral treatment is recommended. Persons in the community who are at high risk for severe COVID-19 illness and eligible for antiviral treatment should seek testing from health care providers with the goal of obtaining a more sensitive diagnostic test than antigen tests (i.e., an RT-PCR test).

Screening Strategies to Reduce COVID-19 Mortality in Nursing Homes.

Importance: Nursing home residents continue to bear a disproportionate share of COVID-19 morbidity and mortality, accounting for 9% of all US COVID-19 deaths in 2023, despite comprising only 0.4% of the population. Objective: To evaluate the cost-effectiveness of screening strategies in reducing COVID-19 mortality in nursing homes. Design and Setting: An agent-based model was developed to simulate SARS-CoV-2 transmission in the nursing home setting. Parameters were determined using SARS-CoV-2 virus data and COVID-19 data from the Centers for Medicare & Medicaid Services and US Centers for Disease Control and Prevention that were published between 2020 and 2023, as well as data on nursing homes published between 2010 and 2023. The model used in this study simulated interactions and SARS-CoV-2 transmission between residents, staff, and visitors in a nursing home setting. The population used in the simulation model was based on the size of the average US nursing home and recommended staffing levels, with 90 residents, 90 visitors (1 per resident), and 83 nursing staff members. Exposure: Screening frequency (none, weekly, and twice weekly) was varied over 30 days against varying levels of COVID-19 community incidence, booster uptake, and antiviral use. Main Outcomes and Measures: The main outcomes were SARS-CoV-2 infections, detected cases per 1000 tests, and incremental cost of screening per life-year gained. Results: Nursing home interactions were modeled between 90 residents, 90 visitors, and 83 nursing staff over 30 days, completing 4000 to 8000 simulations per parameter combination. The incremental cost-effectiveness ratios of weekly and twice-weekly screening were less than $150 000 per resident life-year with moderate (50 cases per 100 000) and high (100 cases per 100 000) COVID-19 community incidence across low-booster uptake and high-booster uptake levels. When COVID-19 antiviral use reached 100%, screening incremental cost-effectiveness ratios increased to more than $150 000 per life-year when booster uptake was low and community incidence was high. Conclusions and Relevance: The results of this cost-effectiveness analysis suggest that screening may be effective for reducing COVID-19 mortality in nursing homes when COVID-19 community incidence is high and/or booster uptake is low. Nursing home administrators can use these findings to guide planning in the context of widely varying levels of SARS-CoV-2 transmission and intervention measures across the US.

Persistent pollution of genetic materials in a typical laboratory environment.

From the onset of coronavirus disease (COVID-19) pandemic, there are concerns regarding the disease spread and environmental pollution of biohazard since studies on genetic engineering flourish and numerous genetic materials were used such as the nucleic acid test of the severe acute respiratory syndrome coronavirus (SARS-CoV-2). In this work, we studied genetic material pollution in an institute during a development cycle of plasmid, one of typical genetic materials, with typical laboratory settings. The pollution source, transmission routes, and pollution levels in laboratory environment were examined. The Real-Time quantitative- Polymerase Chain Reaction results of all environmental mediums (surface, aerosol, and liquid) showed that a targeted DNA segment occurred along with routine experimental operations. Among the 79 surface and air samples collected in the genetic material operation, half of the environment samples (38 of 79) are positive for nucleic acid pollution. Persistent nucleic acid contaminations were observed in all tested laboratories and spread in the public area (hallway). The highest concentration for liquid and surface samples were 1.92 × 108 copies/uL and 5.22 × 107 copies/cm2, respectively. Significant amounts of the targeted gene (with a mean value of 74 copies/L) were detected in the indoor air of laboratories utilizing centrifuge devices, shaking tables, and cell homogenizers. Spills and improper disposal of plasmid products were primary sources of pollution. The importance of establishing designated experimental zones, employing advanced biosafety cabinets, and implementing highly efficient cleaning systems in laboratories with lower biosafety levels is underscored. SYNOPSIS: STATEMENT. Persistent environmental pollutions of genetic materials are introduced by typical experiments in laboratories with low biosafety level.

A quanta-independent approach for the assessment of strategies to reduce the risk of airborne infection.

The Wells-Riley model is extensively used for retrospective and prospective modelling of the risk of airborne transmission of infection in indoor spaces. It is also used when examining the efficacy of various removal and deactivation methods for airborne infectious aerosols in the indoor environment, which is crucial when selecting the most effective infection control technologies. The problem is that the large variation in viral load between individuals makes the Wells-Riley model output very sensitive to the input parameters and may yield a flawed prediction of risk. The absolute infection risk estimated with this model can range from nearly 0 % to 100 % depending on the viral load, even when all other factors, such as removal mechanisms and room geometry, remain unchanged. We therefore propose a novel method that removes this sensitivity to viral load. We define a quanta-independent maximum absolute before-after difference in infection risk that is independent of quanta factors like viral load, physical activity, or the dose-response relationships. The input data needed for a non-steady-state calculation are just the removal rates, room volume, and occupancy duration. Under steady-state conditions the approach provides an elegant solution that is only dependent on removal mechanisms before and after applying infection control measures. We applied this method to compare the impact of relative humidity, ventilation rate and its effectiveness, filtering efficiency, and the use of ultraviolet germicidal irradiation on the infection risk. The results demonstrate that the method provides a comprehensive understanding of the impact of infection control strategies on the risk of airborne infection, enabling rational decisions to be made regarding the most effective strategies in a specific context. The proposed method thus provides a practical tool for mitigation of airborne infection risk.

SARS-CoV-2 Transmission in Alberta, British Columbia, and Ontario, Canada, January 2020-January 2022.

We estimated COVID-19 transmission potential and case burden by variant type in Alberta, British Columbia, and Ontario, Canada, during January 23, 2020-January 27, 2022; we also estimated the effectiveness of public health interventions to reduce transmission. We estimated time-varying reproduction number (Rt) over 7-day sliding windows and nonoverlapping time-windows determined by timing of policy changes. We calculated incidence rate ratios (IRRs) for each variant and compared rates to determine differences in burden among provinces. Rt corresponding with emergence of the Delta variant increased in all 3 provinces; British Columbia had the largest increase, 43.85% (95% credible interval [CrI] 40.71%-46.84%). Across the study period, IRR was highest for Omicron (8.74 [95% CrI 8.71-8.77]) and burden highest in Alberta (IRR 1.80 [95% CrI 1.79-1.81]). Initiating public health interventions was associated with lower Rt and relaxing restrictions and emergence of new variants associated with increases in Rt.

Modeling county level COVID-19 transmission in the greater St. Louis area: Challenges of uncertainty and identifiability when fitting mechanistic models to time-varying processes.

We use a compartmental model with a time-varying transmission parameter to describe county level COVID-19 transmission in the greater St. Louis area of Missouri and investigate the challenges in fitting such a model to time-varying processes. We fit this model to synthetic and real confirmed case and hospital discharge data from May to December 2020 and calculate uncertainties in the resulting parameter estimates. We also explore non-identifiability within the estimated parameter set. We find that the death rate of infectious non-hospitalized individuals, the testing parameter and the initial number of exposed individuals are not identifiable based on an investigation of correlation coefficients between pairs of parameter estimates. We also explore how this non-identifiability ties back into uncertainties in the estimated parameters and find that it inflates uncertainty in the estimates of our time-varying transmission parameter. However, we do find that R0 is not highly affected by non-identifiability of its constituent components and the uncertainties associated with the quantity are smaller than those of the estimated parameters. Parameter values estimated from data will always be associated with some uncertainty and our work highlights the importance of conducting these analyses when fitting such models to real data. Exploring identifiability and uncertainty is crucial in revealing how much we can trust the parameter estimates.

The effect of nonpharmaceutical interventions on influenza virus transmission.

Background: The use of nonpharmaceutical interventions (NPIs) during severe acute respiratory syndrome 2019 (COVID-19) outbreaks may influence the spread of influenza viruses. This study aimed to evaluate the impact of NPIs against SARS-CoV-2 on the epidemiological features of the influenza season in China. Methods: We conducted a retrospective observational study analyzing influenza monitoring data obtained from the China National Influenza Center between 2011 and 2023. We compared the changes in influenza-positive patients in the pre-COVID-19 epidemic, during the COVID-19 epidemic, and post-COVID-19 epidemic phases to evaluate the effect of NPIs on influenza virus transmission. Results: NPIs targeting COVID-19 significantly suppressed influenza activity in China from 2019 to 2022. In the seventh week after the implementation of the NPIs, the number of influenza-positive patients decreased by 97.46% in southern regions of China and 90.31% in northern regions of China. However, the lifting of these policies in December 2022 led to an unprecedented surge in influenza-positive cases in autumn and winter from 2022 to 2023. The percentage of positive influenza cases increased by 206.41% (p < 0.001), with high positivity rates reported in both the northern and southern regions of China. Conclusion: Our findings suggest that NPIs against SARS-CoV-2 are effective at controlling influenza epidemics but may compromise individuals' immunity to the virus.

A tale of lockdown policies on the transmission of COVID-19 within and between Chinese cities: A study based on heterogeneous treatment effect.

During the early outbreak phase of COVID-19 in China, lockdowns prevailed as the only available policy tools to mitigate the spread of infection. To evaluate the impact of lockdown policies in the context of the first phase of COVID-19 pandemic, we leverage data on daily confirmed cases per million people and related characteristics of a large set of cities. The study analyzed 369 Chinese cities, among which 188 implemented lockdowns of varying severity levels from January 23 to March 31, 2020. We use nationwide Baidu Mobility data to estimate the impact of lockdown policies on mitigating COVID-19 cases through reducing human mobility. We adopt a heterogeneous treatment effect model to quantify the effect of lockdown policies on containing confirmed case counts. Our results suggest that lockdowns substantially reduced human mobility, and larger reduction in mobility occurred within-city compared to between-city. The COVID-19 daily confirmed cases per million people decreased by 9% - 9.2% for every ten-percentage point fall in within-city travel intensity in t+7 timeframe. We also find that one city's lockdowns can effectively reduce the spillover cases of the traveler's destination cities. We find no evidence that stricter lockdowns are more effective at mitigating COVID-19 risks. Our findings provide practical insights about the effectiveness of NPI during the early outbreak phase of the unprecedented pandemic.

SARS-CoV and SARS-CoV-2 display limited neuronal infection and lack the ability to transmit within synaptically connected axons in stem cell-derived human neurons.

Sarbecoviruses such as SARS and SARS-CoV-2 have been responsible for two major outbreaks in humans, the latter resulting in a global pandemic. While sarbecoviruses primarily cause an acute respiratory infection, they have been shown to infect the nervous system. However, mechanisms of sarbecovirus neuroinvasion and neuropathogenesis remain unclear. In this study, we examined the infectivity and trans-synaptic transmission potential of the sarbecoviruses SARS and SARS-CoV-2 in human stem cell-derived neural model systems. We demonstrated limited ability of sarbecoviruses to infect and replicate in human stem cell-derived neurons. Furthermore, we demonstrated an inability of sarbecoviruses to transmit between synaptically connected human stem cell-derived neurons. Finally, we determined an absence of SARS-CoV-2 infection in olfactory neurons in experimentally infected ferrets. Collectively, this study indicates that sarbecoviruses exhibit low potential to infect human stem cell-derived neurons, lack an ability to infect ferret olfactory neurons, and lack an inbuilt molecular mechanism to utilise retrograde axonal trafficking and trans-synaptic transmission to spread within the human nervous system.

Digital measurement of SARS-CoV-2 transmission risk from 7 million contacts.

How likely is it to become infected by SARS-CoV-2 after being exposed? Almost everyone wondered about this question during the COVID-19 pandemic. Contact-tracing apps1,2 recorded measurements of proximity3 and duration between nearby smartphones. Contacts-individuals exposed to confirmed cases-were notified according to public health policies such as the 2 m, 15 min guideline4,5, despite limited evidence supporting this threshold. Here we analysed 7 million contacts notified by the National Health Service COVID-19 app6,7 in England and Wales to infer how app measurements translated to actual transmissions. Empirical metrics and statistical modelling showed a strong relation between app-computed risk scores and actual transmission probability. Longer exposures at greater distances had risk similar to that of shorter exposures at closer distances. The probability of transmission confirmed by a reported positive test increased initially linearly with duration of exposure (1.1% per hour) and continued increasing over several days. Whereas most exposures were short (median 0.7 h, interquartile range 0.4-1.6), transmissions typically resulted from exposures lasting between 1 h and several days (median 6 h, interquartile range 1.4-28). Households accounted for about 6% of contacts but 40% of transmissions. With sufficient preparation, privacy-preserving yet precise analyses of risk that would inform public health measures, based on digital contact tracing, could be performed within weeks of the emergence of a new pathogen.

Knowledge of Brazilian Dentists about Dentoalveolar Trauma Care and their Experiences during the COVID-19 Pandemic

ABSTRACT Objective: To assess dentists' knowledge from Minas Gerais, Brazil, about dentoalveolar trauma (DT) and their experiences during the COVID-19 pandemic. Material and Methods: An online questionnaire with 34 questions was applied to collect personal data, professional training, self-assessment of experience/knowledge about DT, experience in care provided during the social distancing, and knowledge/conduct. The specific responses were evaluated based on the guidelines of the International Association of Dental Traumatology (IADT). Descriptive analysis and Pearson's chi-square test were performed. The level of significance was set at p≤0.05. Results: Most professionals (97.7%) had received information on DT, and only 4.6% of the participants considered their knowledge poor or very poor. However, 92.7% felt the need for more information on the subject. Regarding experiences during the pandemic, 55.7% provided trauma care during that period. Forty percent of the consultations were performed in person, and 33.3% of the professionals noted an increase in cases during the pandemic; 56.6% reported that the frequency did not change. The overall mean number of correct answers about DT was 5.29±2.11, indicating an acceptable level of knowledge. The mean percentage of hits for the specific questions was 44.1%. Conclusion: Although the level of knowledge of the dentists evaluated was acceptable, some aspects were deficient, with the need for more information about the IADT guidelines.

Changes in Oral Health-Related Behaviors and Oral Health of Children in Early Childhood during Social Isolation Caused by COVID-19

ABSTRACT Objective: To assess changes in oral health-related behavior and oral health status in Brazilian children in early childhood perceived by their parents/caregivers during social isolation caused by COVID-19. Material and Methods: A cross-sectional study with parents/caregivers of children in southeastern Brazil aged 0-5 years who responded to an online questionnaire about sociodemographic data, dietary changes, oral hygiene, and oral health status of children during the COVID-19 pandemic. Results: Of the 119 parents/caregivers, 54.60% did not observe any changes in eating habits, and 81.50% maintained their children's oral hygiene. Associations were observed between the impact of the pandemic on the family income and changes in eating habits (p=0.02) and between lower family income and dental caries perceived by parents/caregivers (p=0.05). Z tests with Bonferroni correction showed that families with drastic income reduction were more likely to consume lower-cost foods (62.50%) than families with no impact or slight reduction on family income. Parents/caregivers did not identify dental caries (89.10%), toothache (92.40%), and dental trauma (92.40%) in their children. Conclusion: Parents/caregivers of children in southeastern Brazil aged 0-5 years observed behavioral changes in the dietary habits of families whose income was impacted by the pandemic, and their perception of dental caries was significantly associated with family income.

Genomic surveillance reveals dynamic shifts in the connectivity of COVID-19 epidemics.

The maturation of genomic surveillance in the past decade has enabled tracking of the emergence and spread of epidemics at an unprecedented level. During the COVID-19 pandemic, for example, genomic data revealed that local epidemics varied considerably in the frequency of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage importation and persistence, likely due to a combination of COVID-19 restrictions and changing connectivity. Here, we show that local COVID-19 epidemics are driven by regional transmission, including across international boundaries, but can become increasingly connected to distant locations following the relaxation of public health interventions. By integrating genomic, mobility, and epidemiological data, we find abundant transmission occurring between both adjacent and distant locations, supported by dynamic mobility patterns. We find that changing connectivity significantly influences local COVID-19 incidence. Our findings demonstrate a complex meaning of "local" when investigating connected epidemics and emphasize the importance of collaborative interventions for pandemic prevention and mitigation.

Telemonitoramento dos idosos de natal-rn na atenção primária durante a pandemia da covid-19: estudo longitudinal descritivo / Telemonitoring of elderly people from Natal-RN in Primary Care during the COVID-19 pandemic: descriptive longitudinal study / Telemonitoreo de ancianos de Natal-RN en Atención Primaria durante la pandemia de COVID-19: estudio longitudinal descriptivo

Introdução:Atelessaúdese popularizou como uma importante ferramenta na avaliação remota e de prestação de cuidados em saúde.Uma de suas vertentes consiste no monitoramento remoto, também chamado de telemonitoramento ou televigilância,que se difundiu, sobretudo para grupos populacionais vulneráveis, como a população idosa, em especial durante a pandemia da COVID-19. Objetivo:Conhecer o perfil sociodemográfico, o estado de saúde e os comportamentos relacionados à saúde dos idosos monitorados durante a pandemia da COVID-19 no município de Natal-Rio Grande do Norte.Metodologia:Estudo longitudinal descritivo, com três momentos de observação. A amostra foi composta por idosos adscritos a 22 unidades de saúde de Natal, acompanhados por meio de ligações telefônicas, de agostode 2020 a julho de 2021. A análise dos dados foi realizada através do software Epi Info™, versão 7.2.4, a partir de frequências absolutas e relativas, medidas de tendência central e dispersão (média e desvio padrão).Resultados:Participaram do estudo 1.348 idosos. Amaioria era do sexo feminino (63,7%), com média de 70 anos, morava acompanhada(81,8%), esteve assintomática (77,0%), possuía comorbidades (81,5%) e dependia de medicações de uso contínuo (81,9%). Os sintomáticos diminuíram ao longo dos três momentos avaliados e menos de 1% evoluiu ao óbito.Conclusões:O telemonitoramentocontribuiu com a longitudinalidade do cuidado, proporcionando a busca ativa contínua de idosos sintomáticos e fortalecendo as atividades das Unidades de Saúde (AU).

Introduction:Telehealth has become popular as an important tool in the remote assessment and provision of health care. One ofits aspects is remote monitoring, also called telemonitoring or telesurveillance, which has become widespread, especially for vulnerable population groups, such as the elderly population, especially during the COVID-19 pandemic.Objective:To know the sociodemographic profile, health status and health-related behaviors of the elderly monitored during the COVID-19 pandemic in the Natal-Rio Grande do Norte. city.Methodology:Descriptive longitudinal study, with three moments of observation. The sample consisted of elderly people enrolled at 22 health units in Natal, followed up through telephone calls, from August 2020 to July 2021. Data analysis was performed using the Epi Info™ software, version 7.2.4, based on absolute and relative frequencies, measures of central tendency and dispersion (mean and standard deviation).Results:1,348 elderly people participated in the study. Most were female (63.7%), aged 70 years on average, lived with someone (81.8%), were asymptomatic (77.0%), had comorbidities(81.5%) and depended on continuous use (81.9%). Symptomatic cases decreased over the three evaluated moments and less than 1% evolved to death.Conclusions:Telemonitoring contributed to the longitudinality of care, providing continuous active search for symptomatic elderly and strengthening the activities of Health Units (AU).

Introducción: La telesalud se ha vuelto popular como una herramienta importante en la evaluacióny provisión remota de atención médica. Una de sus vertientes es el monitoreo remoto, también llamado telemonitoreo o televigilancia, que se ha generalizado, especialmente para grupos de población vulnerable, como la población de la tercera edad, especialmente durante la pandemia del COVID-19. Objetivo: Conocer el perfil sociodemográfico, el estado de salud y los comportamientos relacionados con la salud de los ancianos acompañados durante la pandemia de COVID-19 en la ciudad de Natal-Rio Grande do Norte.. Metodología: Estudio longitudinal descriptivo, con tres momentos de observación. La muestra estuvo compuesta por ancianos matriculados en 22 unidades de salud de Natal, seguidos a través de llamadas telefónicas, de agosto de 2020 a julio de 2021. El análisis de los datos se realizó mediante el software Epi Info™, versión 7.2.4, con base en valores absolutos y relativos. frecuencias, medidas de tendencia central y dispersión (media y desviación estándar). Resultados: Participaron del estudio 1.348 ancianos. La mayoría eran del sexo femenino (63,7%), con edad media de 70 años, vivían con alguien (81,8%), estaban asintomáticos (77,0%), tenían comorbilidades (81,5%) y dependían del uso continuo (81,9%). Los casos sintomáticos disminuyeron en los tres momentos evaluados y menos del 1% evolucionó a muerte.Conclusiones: La televigilancia contribuyó para la longitudinalidad de la atención, proporcionando búsqueda activa continua de ancianos sintomáticos y fortaleciendo las actividades de las Unidades de Salud (AU).

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.

Detecting Disease Transmission: Comparing SARS-CoV-2 Cases in a County Jail and the Surrounding Community.

Early detection of infectious disease transmission is an important public health tool. We sought to evaluate how positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases, identified within 14 days of admission to a jail setting, are linked to local county incidence. Data were extracted from the electronic health record and publicly accessible websites. We compared positive cases of SARS-CoV-2 identified in the Santa Clara County (SCC) jail within 14 days of admission (250 cases) with positive cases reported in SCC (141,841 cases) between March 15, 2020, and October 2, 2021. There was a strong, positive correlation between cases of SARS-CoV-2 identified within 14 days of jail admission and SCC cases the following week (r = .785). Our findings show that admission SARS-CoV-2 testing data from jails may be useful for detecting disease transmission in the surrounding community.

Human ACE2 protein is a molecular switch controlling the mode of SARS-CoV-2 transmission.

BACKGROUND: Human angiotensin-converting enzyme 2 (hACE2) is the receptor mediating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. hACE2 expression is low in the lungs and is upregulated after SARS-CoV-2 infection. How such a hACE2-limited pulmonary environment supports efficient virus transmission and how dynamic hACE2 expression affects SARS-CoV-2 infection are unclear. METHODS: We generated stable cell lines with different expression levels of hACE2 to evaluate how the hACE2 expression level can affect SARS-CoV-2 transmission. RESULTS: We demonstrated that the hACE2 expression level controls the mode of SARS-CoV-2 transmission. The hACE2-limited cells have an advantage for SARS-CoV-2 shedding, which leads to cell-free transmission. By contrast, enhanced hACE2 expression facilitates the SARS-CoV-2 cell-to-cell transmission. Furthermore, this cell-to-cell transmission is likely facilitated by hACE2-containing vesicles, which accommodate numerous SARS-CoV-2 virions and transport them to neighboring cells through intercellular extensions. CONCLUSIONS: This hACE2-mediated switch between cell-free and cell-to-cell transmission routes provides SARS-CoV-2 with advantages for either viral spread or evasion of humoral immunity, thereby contributing to the COVID-19 pandemic and pathogenesis.