COVID-19: Adaptation of a model to predicting healthcare resources needs in Valle del Cauca, Colombia / COVID-19: Predicción de las necesidades de recursos sanitarios en el Valle del Cauca, Colombia

Abstract Background: Valle del Cauca is the region with the fourth-highest number of COVID-19 cases in Colombia (>50,000 on September 7, 2020). Due to the lack of anti-COVID-19 therapies, decision-makers require timely and accurate data to estimate the incidence of disease and the availability of hospital resources to contain the pandemic. Methods: We adapted an existing model to the local context to forecast COVID-19 incidence and hospital resource use assuming different scenarios: (1) the implementation of quarantine from September 1st to October 15th (average daily growth rate of 2%); (2-3) partial restrictions (at 4% and 8% growth rates); and (4) no restrictions, assuming a 10% growth rate. Previous scenarios with predictions from June to August were also presented. We estimated the number of new cases, diagnostic tests required, and the number of available hospital and intensive care unit (ICU) beds (with and without ventilators) for each scenario. Results: We estimated 67,700 cases by October 15th when assuming the implementation of a quarantine, 80,400 and 101,500 cases when assuming partial restrictions at 4% and 8% infection rates, respectively, and 208,500 with no restrictions. According to different scenarios, the estimated demand for reverse transcription-polymerase chain reaction tests ranged from 202,000 to 1,610,600 between September 1st and October 15th. The model predicted depletion of hospital and ICU beds by September 20th if all restrictions were to be lifted and the infection growth rate increased to 10%. Conclusion: Slowly lifting social distancing restrictions and reopening the economy is not expected to result in full resource depletion by October if the daily growth rate is maintained below 8%. Increasing the number of available beds provides a safeguard against slightly higher infection rates. Predictive models can be iteratively used to obtain nuanced predictions to aid decision-making

Resumen Introducción: Valle del Cauca es el departamento con el cuarto mayor número de casos de COVID-19 en Colombia (>50,000 en septiembre 7, 2020). Debido a la ausencia de tratamientos efectivos para COVID-19, los tomadores de decisiones requieren de acceso a información actualizada para estimar la incidencia de la enfermedad, y la disponibilidad de recursos hospitalarios para contener la pandemia. Métodos: Adaptamos un modelo existente al contexto local para estimar la incidencia de COVID-19, y la demanda de recursos hospitalarios en los próximos meses. Para ello, modelamos cuatro escenarios hipotéticos: (1) el gobierno local implementa una cuarentena desde el primero de septiembre hasta el 15 de octubre (asumiendo una tasa promedio de infecciones diarias del 2%); (2-3) se implementan restricciones parciales (tasas de infección del 4% y 8%); (4) se levantan todas las restricciones (tasa del 10%). Los mismos escenarios fueron previamente evaluados entre julio y agosto, y los resultados fueron resumidos. Estimamos el número de casos nuevos, el número de pruebas diagnósticas requeridas, y el numero de camas de hospital y de unidad de cuidados intensivos (con y sin ventilación) disponibles, para cada escenario. Resultados: El modelo estimó 67,700 casos a octubre 15 al asumir la implementación de una nueva cuarentena, 80,400 y 101,500 al asumir restricciones parciales al 4 y 8% de infecciones diarias, respectivamente, y 208,500 al asumir ninguna restricción. La demanda por pruebas diagnósticas (de reacción en cadena de la polimerasa) fue estimada entre 202,000 y 1,610,600 entre septiembre 1 y octubre 15, a través de los diferentes escenarios evaluados. El modelo estimó un agotamiento de camas de cuidados intensivos para septiembre 20 al asumir una tasa de infecciones del 10%. Conclusión: Se estima que el levantamiento paulatino de las restricciones de distanciamiento social y la reapertura de la economía no debería causar el agotamiento de recursos hospitalarios si la tasa de infección diaria se mantiene por debajo del 8%. Sin embargo, incrementar la disponibilidad de camas permitiría al sistema de salud ajustarse rápidamente a potenciales picos inesperados de infecciones nuevas. Los modelos de predicción deben ser utilizados de manera iterativa para depurar las predicciones epidemiológicas y para proveer a los tomadores de decisiones con información actualizada.

COVID-19: Adaptation of a model to predicting healthcare resources needs in Valle del Cauca, Colombia.

BACKGROUND: Valle del Cauca is the region with the fourth-highest number of COVID-19 cases in Colombia (>50,000 on September 7, 2020). Due to the lack of anti-COVID-19 therapies, decision-makers require timely and accurate data to estimate the incidence of disease and the availability of hospital resources to contain the pandemic. METHODS: We adapted an existing model to the local context to forecast COVID-19 incidence and hospital resource use assuming different scenarios: (1) the implementation of quarantine from September 1st to October 15th (average daily growth rate of 2%); (2-3) partial restrictions (at 4% and 8% growth rates); and (4) no restrictions, assuming a 10% growth rate. Previous scenarios with predictions from June to August were also presented. We estimated the number of new cases, diagnostic tests required, and the number of available hospital and intensive care unit (ICU) beds (with and without ventilators) for each scenario. RESULTS: We estimated 67,700 cases by October 15th when assuming the implementation of a quarantine, 80,400 and 101,500 cases when assuming partial restrictions at 4% and 8% infection rates, respectively, and 208,500 with no restrictions. According to different scenarios, the estimated demand for reverse transcription-polymerase chain reaction tests ranged from 202,000 to 1,610,600 between September 1st and October 15th. The model predicted depletion of hospital and ICU beds by September 20th if all restrictions were to be lifted and the infection growth rate increased to 10%. CONCLUSION: Slowly lifting social distancing restrictions and reopening the economy is not expected to result in full resource depletion by October if the daily growth rate is maintained below 8%. Increasing the number of available beds provides a safeguard against slightly higher infection rates. Predictive models can be iteratively used to obtain nuanced predictions to aid decision-making.

INTRODUCCIÓN: Valle del Cauca es el departamento con el cuarto mayor número de casos de COVID-19 en Colombia (>50,000 en septiembre 7, 2020). Debido a la ausencia de tratamientos efectivos para COVID-19, los tomadores de decisiones requieren de acceso a información actualizada para estimar la incidencia de la enfermedad, y la disponibilidad de recursos hospitalarios para contener la pandemia. MÉTODOS: Adaptamos un modelo existente al contexto local para estimar la incidencia de COVID-19, y la demanda de recursos hospitalarios en los próximos meses. Para ello, modelamos cuatro escenarios hipotéticos: (1) el gobierno local implementa una cuarentena desde el primero de septiembre hasta el 15 de octubre (asumiendo una tasa promedio de infecciones diarias del 2%); (2-3) se implementan restricciones parciales (tasas de infección del 4% y 8%); (4) se levantan todas las restricciones (tasa del 10%). Los mismos escenarios fueron previamente evaluados entre julio y agosto, y los resultados fueron resumidos. Estimamos el número de casos nuevos, el número de pruebas diagnósticas requeridas, y el numero de camas de hospital y de unidad de cuidados intensivos (con y sin ventilación) disponibles, para cada escenario. RESULTADOS: El modelo estimó 67,700 casos a octubre 15 al asumir la implementación de una nueva cuarentena, 80,400 y 101,500 al asumir restricciones parciales al 4 y 8% de infecciones diarias, respectivamente, y 208,500 al asumir ninguna restricción. La demanda por pruebas diagnósticas (de reacción en cadena de la polimerasa) fue estimada entre 202,000 y 1,610,600 entre septiembre 1 y octubre 15, a través de los diferentes escenarios evaluados. El modelo estimó un agotamiento de camas de cuidados intensivos para septiembre 20 al asumir una tasa de infecciones del 10%. Conclusión: Se estima que el levantamiento paulatino de las restricciones de distanciamiento social y la reapertura de la economía no debería causar el agotamiento de recursos hospitalarios si la tasa de infección diaria se mantiene por debajo del 8%. Sin embargo, incrementar la disponibilidad de camas permitiría al sistema de salud ajustarse rápidamente a potenciales picos inesperados de infecciones nuevas. Los modelos de predicción deben ser utilizados de manera iterativa para depurar las predicciones epidemiológicas y para proveer a los tomadores de decisiones con información actualizada.

Efficacy of three different methods for side port incision wound sealing

PURPOSE: To evaluate wound leakage and bacteria-sized particle influx in differently corneal sealed side port incisions. METHODS: Four 1.5mm tunnel squared incisions were created in each of four cadaveric human eyes. In each cornea, one incision was left unsealed, whereas the other three incisions were sealed using a 10-0 nylon suture, cyanoacrylate glue, or stromal hydration, respectively. A Seidel and an India ink test were performed on each eye. During each Seidel test, flourescein was applied, the IOP increased from 15 to 80mmHg, and the IOP at which each incision started to leak recorded. During each India ink test, ink was placed on the eye and rinsed out with balanced salt solution (BSS). Ink penetration was then measured by planimetry at physiologic conditions and after an IOP plunge from 80mmHg to 0mmHg. RESULTS: Regardless of IOP variations, no leakage or ink inflow was observed through the glued incisions. In contrast, leakage did occur in the other three sealing methods, albeit at significantly different IOP levels in each one (p=0.013). Ink inflow occurred in these sealing methods at physiologic IOP and, to a significantly greater extent, after the IOP challenge (p<0.05). At both of these IOP conditions, the differences in ink influx among these three incision-sealing methods were deemed statistically insignificant. CONCLUSION: This study showed that glue was more effective at preventing wound leakage and bacteria-sized particle influx than other commonly used methods especially hydrosealing.

OBJETIVO: Avaliar o sinal de Seidel positivo e a penetração de tinta da Índia em incisões corneanas acessórias seladas por diferentes métodos. MÉTODOS: Quatro incisões de 1,5 x 1,5mm foram criadas em cada um dos quatro olhos provindos do banco de olhos. Em cada córnea, uma incisão foi mantida sem manipulação, enquanto que as outras três incisões foram seladas respectivamente com Nylon 10-0, cola de cianoacrilato e hidratação estromal. Foram realizados dois testes: Sinal de Seidel positivo e penetração da tinta da Índia. No primeiro, foi aplicado fluoresceína gotas e a pressão intraocular (PIO) elevada de 15 para 80mmHg. No segundo, a tinta da Índia foi aplicada sobre o olho estudado em duas situações: sob PIO fisiológica e sob variação súbita da pressão, de 80 para 0mmHg. RESULTADOS: Na incisão selada com cola, apesar da variação da PIO, não houve vazamento e nem penetração de partículas de tinta. Por outro lado, o sinal de Seidel foi positivo nas outras três incisões em diferentes níveis de PIO (p=0,013). A penetração da tinta da Índia ocorreu nestas três incisões sob pressão fisiológica e com maior extensão após a variação da PIO (p<0,05). Esta diferença, no entanto não foi considerada estatisticamente significante quando comparadas as incisões entre si. CONCLUSÃO: No presente estudo, a cola foi mais eficaz em prevenir Seidel e entrada de partículas do que outro método comumente usado especialmente, hidratação estromal.

Assessment of fungal viability after long-wave ultraviolet light irradiation combined with riboflavin administration.

BACKGROUND: Corneal collagen cross-linking (CXL), a technique that combines riboflavin administration with long-wave ultraviolet light irradiation, was primarily developed to increase the biomechanical strength of collagen fibrils of the cornea to avoid the progression of keratoconus. Recently, this method has been proposed to treat selected cases of infectious keratitis. METHODS: To test the protocol used for progressive keratoconus in infectious keratitis, Candida albicans, and Fusarium solani, strains were exposed to irradiation using a wavelength of 365 nm at a power density of 3 mW/cm(2) for 30 min in the presence of riboflavin photosensitizer. All experiments were performed in triplicate. Qualitative and quantitative measurements of fungal viability used plate cultures and an automated trypan blue dye exclusion method respectively. Fungal cell diameter was also assessed in all groups. Statistical analyses were performed using the triplicate values of each experimental condition. RESULTS: Experimental findings of photodynamic therapy applied to the cell inactivation of both yeasts and filamentous fungi were compared with control groups. Qualitative results were corroborated with quantitative findings which showed no statistical significance between challenged samples (experimental groups) and the control group (p-value = 1). In comparison with a control group of live cells, statistical significance was observed when riboflavin solution alone had an effect on the morphologic size of filamentous fungi, while ultraviolet light irradiation alone showed a slight decrease in the cell structure of C. albicans. CONCLUSIONS: The impact of long-wave ultraviolet combined with riboflavin photosensitizer showed no antifungal effect on C. albicans and F. solani. The significant decrease in cell morphology of both filamentous fungi and yeasts submitted to photosensitizing riboflavin and exposure to ultraviolet light, respectively, may be promising in the development and standardization of alternatives for fungal cell inactivation, because of their minimal cytotoxic effects on the corneal surface. The methodological improvement in the preparation and application of individual chemical compounds, such as riboflavin, or physical systems, such as a long-wave light source, as antifungal agents may also assist in establishing promising therapeutic procedures for keratomycosis.

Antimicrobial susceptibility of photodynamic therapy (UVA/riboflavin) against Staphylococcus aureus / Suscetibilidade antimicrobiana da terapia fotodinâmica (UVA/riboflavina) contra Staphylococcus aureus

PURPOSE: To assess S. aureus in vitro viability after the exposure to ultraviolet light A (UVA) and riboflavin (B2). METHODS: Samples of S. aureus in 96 well plates (in triplicate) were exposed to riboflavin (B2) and ultraviolet light A (365 nm wavelength) at a power density of 3 mW/cm², 8 mm spot diameter, for 30 minutes. Control groups were prepared as well in triplicate: blank control, ultraviolet light A only, riboflavin only and dead bacteria Control. The bacterial viability was measured using fluorescent microscopy. In order to investigate the occurrence of "viable but non-culturable" microorganisms after treatment, the cell viability was also investigated by plate culture procedure onto a broth medium. Statistical analysis was performed using the triplicate values from each experimental condition. RESULTS: No difference was observed among the treatment group and the control samples (p=1). CONCLUSION: The combination of riboflavin 0.1% and ultraviolet light A at 365 nm did not exhibit antimicrobial activity against oxacillin susceptible S. aureus.

OBJETIVO: Avaliar a viabilidade celular de S. aureus in vitro após a exposição de riboflavina (B2) e luz ultravioleta A (UVA). MÉTODOS: Amostras de S. aureus colocadas em uma placa de 96 poços (em triplicata) foram expostas a riboflavina 0,1% (B2) e luz ultravioleta (comprimento de onda de 365 nm) poder de 3 mW/cm², 8 mm de diâmetro, por 30 minutos. Grupos controles foram também preparados em triplicata: controle branco, somente luz ultravioleta A, somente riboflavina e controle morto. A viabilidade bacteriana foi analisada usando microscópio de fluorescência. Para investigar a ocorrência de micro-organismos "viáveis porem não cultiváveis" a viabilidade celular foi avaliada utilizando-se placas de meio de cultivo bacteriano. Analise estatística foi realizada utilizando-se os valores obtidos em triplicata de cada grupo experimental. RESULTADOS: Nenhuma diferença foi observada entre o grupo tratamento e os grupos controle (p=1). CONCLUSÃO: A combinação riboflavina 0,1% e luz ultravioleta 365 nm de comprimento de onda não demonstrou atividade antimicrobiana contra S. aureus oxacilina sensível.

Antimicrobial susceptibility of photodynamic therapy (UVA/riboflavin) against Staphylococcus aureus.

PURPOSE: To assess S. aureus in vitro viability after the exposure to ultraviolet light A (UVA) and riboflavin (B2). METHODS: Samples of S. aureus in 96 well plates (in triplicate) were exposed to riboflavin (B2) and ultraviolet light A (365 nm wavelength) at a power density of 3 mW/cm², 8 mm spot diameter, for 30 minutes. Control groups were prepared as well in triplicate: blank control, ultraviolet light A only, riboflavin only and dead bacteria Control. The bacterial viability was measured using fluorescent microscopy. In order to investigate the occurrence of "viable but non-culturable" microorganisms after treatment, the cell viability was also investigated by plate culture procedure onto a broth medium. Statistical analysis was performed using the triplicate values from each experimental condition. RESULTS: No difference was observed among the treatment group and the control samples (p=1). CONCLUSION: The combination of riboflavin 0.1% and ultraviolet light A at 365 nm did not exhibit antimicrobial activity against oxacillin susceptible S. aureus.

Assessing efficacy of combined riboflavin and UV-A light (365 nm) treatment of Acanthamoeba trophozoites.

PURPOSE: To assess the Acanthamoeba trophozoite viability in vitro and treatment of Acanthamoeba keratitis in a hamster model using ultraviolet light A (UV-A) and riboflavin (B2). METHODS: A sample of Acanthamoeba sp. cultured was transferred to a 96-well plate and exposed to B2 and the UV-A light (365 nm wavelength) at a power density of 3 mW/cm(2), 8 mm spot diameter, for 30 minutes. The exposure was done in triplicate. Control groups were prepared in triplicate as well: blank control, UV-A only, riboflavin only, and dead control. Cell viability assessment was done using the trypan blue dye exclusion method. Acanthamoeba keratitis was induced in Chinese hamsters; who were randomly assigned to one of the animal groups: UV-A + B2, propamidine isethionate (Brolene; Sanofi-Aventis, Ellerslie, Auckland, Australia), UV-A + B2 + propamidine isethionate (Brolene), only UV-A, only B2, and blank. Throughout the 14 days after treatment the animals were examined clinically. Histology and clinical scores of all groups were compared. RESULTS: The in vitro study showed no difference between the treatment group UV-A + B2 and the control groups. In the hamster keratitis model a significant improvement of clinical score was observed for the groups propamidine isethionate (Brolene) and UV-A + B2 + propamidine isethionate (Brolene) (P = 0.0067). Also a significant worsening of clinical score was observed in the other groups: UV-A + B2 group (P = 0.0084), only UV-A (P = 0.0078), B2 only (P = 0.0084), and blank (P = 0.0082). No difference was observed between propamidine isethionate (Brolene) and UV-A + B2 + propamidine isethionate (Brolene). CONCLUSIONS: The adjunctive use of UV-A and B2 therapy did not demonstrate antitrophozoite activity; in vivo UV-A and B2 did not demonstrate efficacy in this model.