Effectiveness and Safety of Non-Invasive Neuromodulation for Vision Restoration: A Systematic Review and Meta-Analysis.

We carried out a systematic review and meta-analysis to determine the effectiveness and safety of non-invasive electrical stimulation (NES) for vision restoration. We systematically searched for randomised controlled trials (RCTs) comparing NES with sham stimulation, for vision restoration between 2000 and 2022 in CENTRAL, MEDLINE, EMBASE, and LILACS. The main outcomes were as follows: visual acuity (VA); detection accuracy; foveal threshold; mean sensitivity as the parameter for the visual field; reading performance; contrast sensitivity (CS); electroencephalogram; quality of life (QoL), and safety. Two reviewers independently selected studies, extracted data, and evaluated the risk of bias using the Cochrane risk of bias 2.0 tool. The certainty in the evidence was determined using the GRADE framework. Protocol registration: CRD42022329342. Thirteen RCTs involving 441 patients with vision impairment indicate that NES may improve VA in the immediate post-intervention period (mean difference [MD] = -0.02 logMAR, 95% confidence intervals [CI] -0.08 to 0.04; low certainty), and probably increases QoL and detection accuracy (MD = 0.08, 95% CI -0.25 to 0.42 and standardised MD [SMD] = 0.09, 95% CI -0.58 to 0.77, respectively; both moderate certainty). NES likely results in little or no difference in mean sensitivity (SMD = -0.03, 95% CI -0.53 to 0.48). Compared with sham stimulation, NES increases the risk of minor adverse effects (risk ratio = 1.24, 95% CI 0.99 to 1.54; moderate certainty). The effect of NES on CS, reading performance, and electroencephalogram was uncertain. Our study suggests that although NES may slightly improve VA, detection accuracy, and QoL, the clinical relevance of these findings remains uncertain. Future research should focus on improving the available evidence's precision and consistency.

Transport-controlled growth decoupling for self-induced protein expression with a glycerol-repressible genetic circuit.

Decoupling cell formation from recombinant protein synthesis is a potent strategy to intensify bioprocesses. Escherichia coli strains with mutations in the glucose uptake components lack catabolite repression, display low growth rate, no overflow metabolism, and high recombinant protein yields. Fast growth rates were promoted by the simultaneous consumption of glucose and glycerol, and this was followed by a phase of slow growth, when only glucose remained in the medium. A glycerol-repressible genetic circuit was designed to autonomously induce recombinant protein expression. The engineered strain bearing the genetic circuit was cultured in 3.9 g L-1 glycerol + 18 g L-1 glucose in microbioreactors with online oxygen transfer rate monitoring. The growth was fast during the simultaneous consumption of both carbon sources (C-sources), while expression of the recombinant protein was low. When glycerol was depleted, the growth rate decreased, and the specific fluorescence reached values 17% higher than those obtained with a strong constitutive promoter. Despite the relatively high amount of C-source used, no oxygen limitation was observed. The proposed approach eliminates the need for the substrate feeding or inducers addition and is set as a simple batch culture while mimicking fed-batch performance.

Historical evolution of cancer genomics research in Latin America: a comprehensive visual and bibliometric analysis until 2023.

Background: Cancer genomics, as an interdisciplinary research area within the Global Cancer Research agenda, genomics and precision medicine, its important in research and clinical practice in Latin America. To date, there has been no study investigating evolution of this area in this region. The aim of this study was to evaluate for first time, the historical evolution of cancer genomics research in Latin America. Methods: Bibliometric cross-sectional study of documents on cancer genomics published by Latin American authors until 2023 in Scopus was performed. Statistical and visual analysis was performed with R programming language. Results: A total of 1534 documents were obtained. The first document of cancer genomics research was published in 1997, marking the inception of a 26-year evaluation period that extended until 2023. Among the documents, 74.3% (n = 1140) constituted original articles, followed by 22.7% (n = 349) classified as reviews. International collaboration was observed in 6.5% (n = 100) of the articles. Within the compilation of the ten most prolific authors in this region, 90% of them are from Brazil. This observed pattern extends to affiliations as well, wherein the Universidade de São Paulo emerges as the most active institution (n = 255 documents). This arrangement firmly establishes Brazil's prominence as the preeminent country in the region concerning cancer genomics research, showcasing robust collaboration networks both regionally and intercontinentally. An important transition in the studied hot topics over the last 20 years was identified, from the exploration of the human genome and the characterization of genomic and proteomic cancer profiles (1997-2010) to an in-depth investigation of cancer stem cells and personalized medicine (2011-2023). Among the array of cancer types under study, predominant attention has been directed towards breast, lung, prostate, and leukemia. Conclusion: Over the course of the past 26 years, a favorable and notable evolution has characterized cancer genomics research within Latin America, with Brazil leading the way, which possess a robust network of regional and intercontinental collaboration. Furthermore, the lines of research and hot topics have change in harmony with the region's objectives, strategies, and requisites.

Recombinant protein expression in proteome-reduced cells under aerobic and oxygen-limited regimes.

Industrial cultures are hindered by the physiological complexity of the host and the limited mass transfer capacity of conventional bioreactors. In this study, a minimal cell approach was combined with genetic devices to overcome such issues. A flavin mononucleotide-based fluorescent protein (FbFP) was expressed in a proteome-reduced Escherichia coli (PR). When FbFP was expressed from a constitutive protein generator (CPG), the PR strain produced 47% and 35% more FbFP than its wild type (WT), in aerobic or oxygen-limited regimes, respectively. Metabolic and expression models predicted more efficient biomass formation at higher fluxes to FbFP, in agreement with these results. A microaerobic protein generator (MPG) and a microaerobic transcriptional cascade (MTC) were designed to induce FbFP expression upon oxygen depletion. The FbFP fluorescence using the MTC in the PR strain was 9% higher than that of the WT bearing the CPG under oxygen limitation. To further improve the PR strain, the pyruvate dehydrogenase complex regulator gene was deleted, and the Vitreoscilla hemoglobin was expressed. Compared to oxygen-limited cultures of the WT, the engineered strains increased the FbFP expression more than 50% using the MTC. Therefore, the designed expression systems can be a valuable alternative for industrial cultivations.

Effect of Basic Amino Acids on Folic Acid Solubility.

To prevent neural tube defects and other cardiovascular diseases in newborns, folic acid (FA) is recommended in pregnant women. A daily dose of 600 µg FA consumption is widely prescribed for women during pregnancy and 400 µg for women with childbearing potential. FA is a class IV compound according to the Biopharmaceutics Classification System (BCS) due to its low permeability (1.7 × 10-6 cm/s) and low solubility (1.6 mg/L); therefore, it must be administered via a formulation that enhances its solubility. Studies reported in the literature have proved that co-amorphization and salt formation of a poorly soluble drug with amino acids (AA) can significantly increase its solubility. Although arginine has been used with FA as a supplement, there is no information on the effect of basic AA (arginine and lysine) on the physical and chemical properties of FA-AA binary formulations. The present study implemented a conductimetric titration methodology to find the effective molar ratio to maximize FA solubility. The results showed that a 1:2.5 FA:AA molar ratio maximized solubility for arginine and lysine. Binary formulations were prepared using different methods, which led to an amorphous system confirmed by the presence of a glass transition, broad FTIR bands, and the absence of an X-ray diffraction pattern. Results of FA:AA (1:2.5) solubility increased in the range of 5500-6000 times compared with pure FA. In addition to solubility enhancement, the binary systems presented morphological properties that depend on the preparation method and whose consideration could be strategic for scaling purposes.

Agave fructans: a review of their technological functionality and extraction processes.

Fructans are a polydisperse mixture of fructose polymers generally bound to a glucose molecule, in recent years, interest in their use has grown, either as a potential ingredient in functional foods or for their technological properties. The diversity of its applications lies in its structure and origin. Until now, the scientific approach has been more focused on inulin-type fructans and not so much on the effect of those of mixed branched structure as agave fructans. These have a complex structure with the presence of ß (2 - 1) and ß (2 - 6) bonds that give it prebiotic properties. In this context, a review is made of the general processes of extraction of agave fructans, as well as their technological functionality in the obtaining of base structures for the development of food products.

Co-administration of bromocriptine and corticosterone produces short- and long-lasting reduction in intake of high-fat food in male rats.

Dopaminergic and glucocorticoid activity has been associated with reduced food consumption; however, their possible synergic action has not yet been studied. With the aim of examining the effect of the co-administration of the dopamine receptor D2 agonist bromocriptine and corticosterone on palatable food intake, male Wistar rats were administered either bromocriptine (1 mg/kg), corticosterone (2 mg/kg), bromocriptine + corticosterone (1 mg + 2 mg/kg) or a vehicle, with a fifth group used as a control. In all cases, substances were administered 30 min before exposure to standard food or palatable food, the latter high in carbohydrates [high carbohydrate food (HCF), 75%] or high-fat food (HFF, 67%). Food consumption and body weight were recorded daily. Results showed higher consumption of standard food but lower consumption of HCF and HFF in the groups that received bromocriptine, alone or in combination. In general, lower total kcal intake was observed in the bromocriptine and bromocriptine + corticosterone groups during the period of pharmacological treatment and following re-exposure to palatable food. The low HFF intake in the bromocriptine + corticosterone group persisted 10 days after the pharmacological treatment was interrupted. This effect suggests plastic changes in either the mechanisms involved in the incentive value of palatable food - particularly foods with high-fat content - or those that regulate lipid metabolism. Our findings suggest that homeostatic and reward mechanisms could be influenced by the co-participation of the dopaminergic and hypothalamic-pituitary-adrenal systems, and the macronutrient content of food.

Comparative study of four extraction methods of fructans (agavins) from Agave durangensis: Heat treatment, ultrasound, microwave and simultaneous ultrasound-microwave.

Agavins (fructans from the agave plant) are used for their technological and prebiotic properties in developing functional foods. In this study, four extraction methods were evaluated: ultrasound (U), microwave (M), simultaneous ultrasound-microwave (UM), and heat treatment (HT). Isomers with a degree of polymerization (DP) > 10, as well as a significant concentration of fructooligosaccharides (FOS) were identified. The yield obtained by UM (72%) was similar to the other methods; however, the extraction time was shorter (5 min). In U, M, and HT the yields were 86, 76, and 85% in 35, 30, and 180 min, respectively. In addition, FTIR spectra showed evidence of regions corresponding to fatty acids and carbohydrates. Therefore, using UM to obtain agavins is a more ecological and faster process.

Patient and Provider Perspectives of Telehealth and In-Person Interventional Radiology Clinic Visits.

PURPOSE: To assess patient and provider satisfaction with interventional radiology (IR) outpatient telehealth and in-person clinic. MATERIALS AND METHODS: This institutional review board-approved study analyzed patient satisfaction with clinic via survey after an IR outpatient telehealth or in-person visit. A physician telehealth experience survey was completed by 8 IR physicians. RESULTS: During the initial survey period, 44 (83%) of 53 patients completed a survey via telephone compared with 37 (23%) of 158 patients who were offered an electronic survey during the second survey period. Of 81 respondents, 18 (22%) were in-person and 63 (78%) were via telehealth. Of the respondents, nearly all patients (97%) in the telehealth group reported satisfaction with their telehealth clinic visit, with similar rates of high patient satisfaction between in-person and telehealth visits (P = .51). Most patients (98%) in the telehealth group strongly agreed that their physician's recommendations were clear in the telehealth visit and that their visit was private, similar to in-person visits (P = .13). A telehealth visit saved time for all patients (100%), with 78% reporting >1 hour of time-saving. All IR physicians (n = 8) reported greater efficiency with telehealth clinic than with in-person clinic and that follow-up patterns would change if telehealth was available. However, all providers (100%) found telephone visits less satisfying than in-person visits, with video visits being either equally satisfying (71%) or less satisfying (29%). CONCLUSIONS: Patient satisfaction with the in-person and telehealth outpatient IR clinic was high, with patients and providers reporting time-saving and greater efficiency with telehealth, suggesting that telehealth should remain an important component of outpatient IR clinic care.

Long-term phytoplankton dynamics in the Zeeschelde estuary (Belgium) are driven by the interactive effects of de-eutrophication, altered hydrodynamics and extreme weather events.

We studied how changing human impacts affected phytoplankton dynamics in the freshwater and brackish tidal reaches of the Zeeschelde estuary (Belgium) between 2002 and 2018. Until the early 2000s, the Zeeschelde was heavily polluted due to high wastewater discharges. By 2008, water quality had improved, resulting in lower nutrient concentrations and higher oxygen levels. Since 2009, however, increased dredging activities resulted in altered hydrodynamics and increased suspended sediment concentration. The combined effects of these environmental changes were reflected in three marked transitions in phytoplankton community composition. Assemblages were dominated by Thalassiosirales and green algae (especially Scenedesmaceae) until 2003. The period 2003-2011 was characterized by the wax and wane of the centric diatoms Actinocyclus and Aulacoseira, while in the period 2012-2018 Thalassiosirales and Cyanobacteria became dominant, the latter mainly imported from the tributaries. Phytoplankton biomass increased sharply in 2003, after which there was a gradual decline until 2018. By 2018, the timing of the growing season had advanced with about one month compared to the start of the study, probably as a consequence of climate warming and intensified zooplankton grazing pressure. Our study shows that de-eutrophication (during the 2000s) and morphological interventions in the estuary (in the 2010s) were dominant drivers of phytoplankton dynamics but that the main shifts in community composition were triggered by extreme weather events, suggesting significant resistance of autochthonous communities to gradual changes in the environment.

Phakic iris-claw intraocular lens: calculations of power and long-term endothelial cells loss.

A correction about phakic intraocular lens power calculation process, as it was stated by Li, Song & Song, is provided. It is explained that this calculation is based on the Van der Heijde formula and not on biometric formulas. A comment about the mechanisms of late endothelial cell loss following phakic intraocular lenses is done.

Natural pigments of plant origin: Classification, extraction and application in foods.

Color is the first attribute that influences the acceptance of foods as they become more attractive to consumers when they are more intense and uniform. In recent years, the interest of producers and consumers in purchasing products containing natural ingredients have constantly increased. Natural pigments are commonly extracted from fruits and vegetables, and have been proven to provide health benefits to reduce the risk of diseases such as type-1 diabetes, obesity, and coronary diseases. Additionally, advanced extraction and encapsulation technologies that make food matrices more efficient are useful tools for improving the use of these pigments. In this review, the state-of-the-art of pigments such as carotenoids, anthocyanins, and betalains of plant origin are discussed, including their main sources of production and the factors that affect their physicochemical stability. In addition, different extraction methods are discussed, listing their advantages and disadvantages, and providing some applications of natural pigments in food.

Mechanical Activation by Ball Milling as a Strategy to Prepare Highly Soluble Pharmaceutical Formulations in the Form of Co-Amorphous, Co-Crystals, or Polymorphs.

Almost half of orally administered active pharmaceutical ingredients (APIs) have low solubility, which affects their bioavailability. In the last two decades, several alternatives have been proposed to modify the crystalline structure of APIs to improve their solubility; these strategies consist of inducing supramolecular structural changes in the active pharmaceutical ingredients, such as the amorphization and preparation of co-crystals or polymorphs. Since many APIs are thermosensitive, non-thermal emerging alternative techniques, such as mechanical activation by milling, have become increasingly common as a preparation method for drug formulations. This review summarizes the recent research in preparing pharmaceutical formulations (co-amorphous, co-crystals, and polymorphs) through ball milling to enhance the physicochemical properties of active pharmaceutical ingredients. This report includes detailed experimental milling conditions (instrumentation, temperature, time, solvent, etc.), as well as solubility, bioavailability, structural, and thermal stability data. The results and description of characterization techniques to determine the structural modifications resulting from transforming a pure crystalline API into a co-crystal, polymorph, or co-amorphous system are presented. Additionally, the characterization methodologies and results of intermolecular interactions induced by mechanical activation are discussed to explain the properties of the pharmaceutical formulations obtained after the ball milling process.

Glucose transport engineering allows mimicking fed-batch performance in batch mode and selection of superior producer strains.

BACKGROUND: Fed-batch mode is the standard culture technology for industrial bioprocesses. Nevertheless, most of the early-stage cell and process development is carried out in batch cultures, which can bias the initial selection of expression systems. Cell engineering can provide an alternative to fed-batch cultures for high-throughput screening and host selection. We have previously reported a library of Escherichia coli strains with single and multiple deletions of genes involved in glucose transport. Compared to their wild type (W3110), the mutant strains displayed lower glucose uptake, growth and aerobic acetate production rates. Therefore, when cultured in batch mode, such mutants may perform similar to W3110 cultured in fed-batch mode. To test that hypothesis, we evaluated the constitutive expression of the green fluorescence protein (GFP) in batch cultures in microbioreactors using a semi defined medium supplemented with 10 or 20 g/L glucose + 0.4 g yeast extract/g glucose. RESULTS: The mutant strains cultured in batch mode displayed a fast-growth phase (growth rate between 0.40 and 0.60 h-1) followed by a slow-growth phase (growth rate between 0.05 and 0.15 h-1), similar to typical fed-batch cultures. The phase of slow growth is most probably caused by depletion of key amino acids. Three mutants attained the highest GFP fluorescence. Particularly, a mutant named WHIC (ΔptsHIcrr, ΔmglABC), reached a GFP fluorescence up to 14-fold greater than that of W3110. Strain WHIC was cultured in 2 L bioreactors in batch mode with 100 g/L glucose + 50 g/L yeast extract. These cultures were compared with exponentially fed-batch cultures of W3110 maintaining the same slow-growth of WHIC (0.05 h-1) and using the same total amount of glucose and yeast extract than in WHIC cultures. The WHIC strain produced approx. 450 mg/L GFP, while W3110 only 220 mg/L. CONCLUSION: The combination of cell engineering and high throughput screening allowed the selection of a particular mutant that mimics fed-batch behavior in batch cultures. Moreover, the amount of GFP produced by the strain WHIC was substantially higher than that of W3110 under both, batch and fed-batch schemes. Therefore, our results represent a valuable technology for accelerated bioprocess development.

Global transcriptomic response of Escherichia coli to p-coumaric acid.

The aromatic compound p-coumaric acid (p-CA) is a secondary metabolite produced by plants. This aromatic acid and derived compounds have positive effects on human health, so there is interest in producing them in biotechnological processes with recombinant Escherichia coli strains. To determine the physiologic response of E. coli W3110 to p-CA, dynamic expression analysis of selected genes fused to a fluorescent protein reporter as well as RNA-seq and RT-qPCR were performed. The observed transcriptional profile revealed the induction of genes involved in functions related to p-CA active export, synthesis of cell wall and membrane components, synthesis of amino acids, detoxification of formaldehyde, phosphate limitation, acid stress, protein folding and degradation. Downregulation of genes encoding proteins involved in energy production, carbohydrate import and metabolism, as well as several outer and plasma membrane proteins was detected. This response is indicative of cell envelope damage causing the leakage of intracellular components including amino acids and phosphate-containing compounds. The cellular functions responding to p-CA that were identified in this study will help in defining targets for production strains improvement.

[The impact of COVID-19 on sick leave of the persons working in nursing homes in Spain. Usefulness of sick leave for the surveillance of the pandemic evolution.] / El impacto de la Covid-19 en la incapacidad temporal de las personas que trabajan en centros socio-sanitarios en España. Utilidad de la incapacidad temporal para el seguimiento de la evolución de la pandemia.

OBJECTIVE: The nursing homes represented high-risk settings for SARS-CoV-2 infection, both for residents and for the employees. The COVID-19 impact on long-term care facilities (LTCFs) is evaluated, measured through the employees sick leave (SL). The pandemic evolution in the general population aged between 16 and 65 years was analyzed together with the sick leave to assess the latter as a complementary indicator of the SARS-CoV-2 surveillance. METHODS: A descriptive study of all sick leave processes due to COVID-19 recorded between February 15th 2020 and May 1st 2021 in nursing homes was carried out. The close contact sick leave/infection sick leave ratios, the 100,000 affiliated/occupied sick leave rates were computed and compared with the COVID-19 cases cumulative incidence notified to the National Network of epidemiological Surveillance (RENAVE). RESULTS: 261.892 SL processes were recorded. The close contact sick leave/infection sick leave median ratio in nursing homes was 1.8 (Interquartile range, ICR: 1.1-3.3), with values lower than 1 at certain periods. The infection sick leaves were higher in number and ratio and prior to the cases recorded in RENAVE. The sick leave ratio ranged between 81.679/100.000 occupied in nursing homes with medical care and 4.895/100.000 in other residential facilities. CONCLUSIONS: The results confirmed the dramatic impact of COVID-19 in nursing homes and the inequalities characterizing this impact. They also confirmed the potential use of sick leave as an alternative source for epidemiological and public health surveillance, especially now, when the transition of the COVID-19 surveillance to a system not including universal individual surveillance is being discussed.

OBJETIVO: Los centros sociosanitarios representaron entornos de alto riesgo de contagio por SARS-CoV-2, tanto para los residentes como para las personas trabajadoras. Se evaluó el impacto en términos de incapacidad temporal (IT) por COVID-19 en las personas que trabajan en centros sociosanitarios y se comparó con la evolución de la pandemia en la población general de 16 a 65 años, para valorar la utilidad de la IT como indicador complementario de la epidemia por SARS-CoV-2. METODOS: Se realizó un estudio descriptivo de todos los procesos de incapacidad temporal por COVID-19 registrados entre el 15 de febrero de 2020 y el 1 de mayo de 2021 en establecimientos residenciales. Se obtuvieron las ratios de incapacidad temporal por contacto estrecho /incapacidad temporal por infección, las tasas de incapacidad temporal por 100.000 afiliados/ocupados y se compararon con la incidencia acumulada de casos COVID-19 notificados a la Red Nacional de Vigilancia Epidemiológica (RENAVE). RESULTADOS: Se registraron 261.892 procesos de incapacidad temporal. La mediana de la ratio de incapacidad temporal por contacto estrecho /incapacidad temporal por infección en residencias fue de 1,8 (Rango intercuartílico, RIC: 1,1-3,3), con valores menores a 1 en periodos. Las IT por infección fueron superiores en número, tasa y anteriores en el tiempo a los casos registrados en RENAVE. Por tipo de residencia, la tasa de incapacidad temporal osciló entre 81.679/100.000 ocupados en asistencia en establecimientos residenciales con cuidados sanitaros y 4.895/100.000 en otros establecimientos residenciales. CONCLUSIONES: Los resultados confirmaron el enorme impacto que tuvo la COVID-19 en los centros sociosanitarios y la desigualdad que ha caracterizado este impacto. Apoyan también la posible utilización de la incapacidad temporal como fuente de información alternativa para la vigilancia epidemiológica y de salud pública, lo cual resulta de especial interés en este momento en el que se está planteando una transición en la vigilancia del COVID-19 hacia un sistema que ya no incluya una vigilancia individualizada universal.

El impacto de la COVID-19 en la incapacidad temporal de las personas que trabajan en centro / The impact of COVID-19 on sick leave of the persons working in nursing homes in Spain. Usefulness of sick leave for the surveillance of the pandemic evolution

Fundamentos: Los centros sociosanitarios representaron entornos de alto riesgo de contagio por SARS-CoV-2, tanto para los residentes como para las personas trabajadoras. Se evaluó el impacto en términos de incapacidad temporal (IT) por COVID-19 en las personas que trabajan en centros sociosanitarios y se comparó con la evolución de la pandemia en la población general de 16 a 65 años, para valorar la utilidad de la IT como indicador complementario de la epidemia por SARS-CoV-2. Métodos: Se realizó un estudio descriptivo de todos los procesos de incapacidad temporal por COVID-19 registrados entre el 15 de febrero de 2020 y el 1 de mayo de 2021 en establecimientos residenciales. Se obtuvieron las ratios de incapacidad temporal por contacto estrecho /incapacidad temporal por infección, las tasas de incapacidad temporal por 100.000 afiliados/ocupados y se compararon con la incidencia acumulada de casos COVID-19 notificados a la Red Nacional de Vigilancia Epidemiológica (RENAVE). Resultados: Se registraron 261.892 procesos de incapacidad temporal. La mediana de la ratio de incapacidad temporal por contacto estrecho /incapacidad temporal por infección en residencias fue de 1,8 (Rango intercuartílico, RIC: 1,13,3), con valores menores a 1 en periodos. Las IT por infección fueron superiores en número, tasa y anteriores en el tiempo a los casos registrados en RENAVE. Por tipo de residencia, la tasa de incapacidad temporal osciló entre 81.679/100.000 ocupados en asistencia en establecimientos residenciales con cuidados sanitaros y 4.895/100.000 en otros establecimientos residenciales. Conclusiones: Los resultados confirmaron el enorme impacto que tuvo la COVID-19 en los centros sociosanitarios y la desigualdad que ha caracterizado este impacto.(AU)

Background: The nursing homes represented highrisk settings for SARS-CoV-2 infection, both for residents and for the employees. The COVID-19 impact on longterm care facilities (LTCFs) is evaluated, measured through the emplo yees sick leave (SL). The pandemic evolution in the general population aged between 16 and 65 years was analyzed together with the sick leave to assess the latter as a complementary indicator of the SARS-CoV-2 surveillance. Methods: A descriptive study of all sick leave processes due to COVID-19 recorded between February 15th 2020 and May 1st 2021 in nursing homes was carried out. The close contact sick leave/infection sick leave ratios, the 100,000 affiliated/occupied sick leave rates were computed and compared with the COVID-19 cases cumulative incidence notified to the National Network of epidemiological Surveillance (RENAVE). Results: 261.892 SL processes were recorded. The close contact sick leave/infection sick leave median ratio in nursing homes was 1.8 (Interquartile range, ICR: 1.1-3.3), with values lower than 1 at certain periods. The infection sick leaves were higher in number and ratio and prior to the cases recorded in RENAVE. The sick leave ratio ranged between 81.679/100.000 occupied in nursing homes with medical care and 4.895/100.000 in other residential facilities. Conclusions: The results confirmed the dramatic impact of COVID-19 in nursing homes and the inequalities characterizing this impact. They also confirmed the potential useof sick leave as an alternative source for epidemiological and public health surveillance, especially now, when the transition of the COVID-19 surveillance to a system not including universal individual surveillance is being discussed.(AU)