Modelo estadístico para estimar el impacto histórico de la influenza sobre la mortalidad en Cuba / Statistical model to estimate the historical impact of influenza on mortality in Cuba

Introducción: La influenza tiene elevado impacto en la mortalidad humana y en Cuba la categoría influenza y neumonía ocupa el cuarto lugar entre sus causales generales. En los países templados, con marcada estacionalidad, esto se capta con modelos estadísticos, tarea que se dificulta en el trópico y pendiente en Cuba por la ausencia de igual definición estacional. Objetivo: Estimar el impacto histórico de la influenza tipo A y B y los subtipos A(H3N2) y A(H1N1) sobre la mortalidad mediante el ajuste de un modelo de regresión a las condiciones estacionales específicas de Cuba. Métodos: Se ejecutó un estudio longitudinal y retrospectivo. En un primer paso se ajustaron dos modelos de Poisson con la mortalidad influenza y neumonía total y las personas ≥ 65 años de edad como variables respuestas en los cinco meses de mayor positividad en influenza, desde la temporada 1987-1988 hasta la 2004-2005 y los positivos en tipo A y en tipo B como explicatorias. En otro par de modelos se estimó el impacto del A(H3N2) y el A(H1N1), considerando como respuesta los fallecidos atribuidos previamente al tipo A. Resultados: Se atribuyeron a la influenza 7803 fallecidos entre todas las edades y 6152 entre las personas ≥ 65 años de edad, con un 56,3 por ciento asociados al A(H3N2), el 17,6 por ciento al A(H1N1) y el 26,1 por ciento al tipo B. Conclusiones. Se logró estimar el impacto de la influenza sobre la mortalidad mediante el ajuste para Cuba de un modelo estadístico que permitió demostrar la asociación de la circulación de estos virus con la mortalidad en el país, lo que ratifica la necesidad de reforzar la vigilancia, el control y la vacunación contra esta infección viral. Se demuestra la posibilidad de ajustar estos modelos de regresión a otros virus respiratorios y a la actual pandemia por la COVID-19, en las condiciones estacionales de Cuba(AU)

Introduction: Influenza has a high impact on human mortality and in Cuba influenza and pneumonia rank fourth among its general causes. In temperate climate countries, with marked seasonality, this is captured by statistical models, a task that is difficult in the tropics and pending in Cuba due to the absence of the same seasonal definition. Objective: Estimate the historical impact of influenza type A and B and subtypes A(H3N2) and A(H1N1) on mortality, by adjusting a regression model to the specific seasonal conditions of Cuba. Methods: A longitudinal and retrospective study was performed. In a first step, two Poisson models were adjusted with influenza and total pneumonia mortality and people ≥ 65 years old as response variables in the five months with the highest positivity to influenza in the period 1987-1988 to 2004-2005, and the positive ones to type A and type B as explanatory variables. In another pair of models was estimated the impact of A(H3N2) and A(H1N1), considering as a response the deaths previously attributed to type A. Results: 7 803 deaths among all ages and 6 152 among 65-year-olds were attributed to influenza, with 56.3 percent associated to A(H3N2), 17.6 percent to A(H1N1) and 26.1 percent to type B. Conclusions: It was possible to estimate the impact of influenza on mortality by adjusting for Cuba a statistical model that demonstrated the association of the circulation of these viruses with the mortality in the country, which confirms the need to strengthen surveillance, control and vaccination against this viral infection. The possibility of adjusting in the seasonal conditions of Cuba these regression models to other respiratory viruses and the current pandemic by COVID-19 is demonstrated(AU)

Interferon gamma, TGF-ß1 and RANTES expression in upper airway samples from SARS-CoV-2 infected patients.

Upper respiratory tract is the primary site of SARS-CoV-2 replication. Releasing of pro and anti-inflammatory mediators plays an important role in the immunopathogenesis of Coronavirus Disease 2019 (COVID-19). The aim of this study was to evaluate the early inflammatory response in upper airway by measuring of IFN-γ, TGF-ß1 and RANTES at mRNA level. Forty five SARS-CoV-2 infected patients were enrolled, whose were divided in two groups: asymptomatic and symptomatic. Twenty healthy persons, SARS-CoV-2 negative were included as controls. Higher IFN-γ expression was detected in SARS-CoV-2 infected patients in comparison with controls (p = 0.0393). IFN-γ expression was increased in symptomatic patients (p = 0.0405). TGF-ß1 and RANTES expressions were lower in SARS-CoV-2 infected patients than controls (p < 0.0001; p = 0.0011, respectively). A significant correlation between IFN-γ and TGF-ß1 was observed in SARS-CoV-2 asymptomatic patients (r = +0.61, p = 0.0014). The findings suggest that imbalance between IFN-γ and TGF-ß1 expression could be an impact in clinical expression of SARS-CoV-2 infection.