Understanding the COVID-19 prevention and control strategies and their appropriate applicability through the basics of epidemiology

The current article is about the background knowledge of corona, various epidemiological definitions and different strategies adopted to prevent and control corona infection. How the preventive measures are applied and what is epidemiological basis behind these measures is the core of the article. The article also mentioned the variations in mortality pattern and goes on defining important indicators as case-fatality ratio, deaths/1 lakh population and the relevance of both in the current situation of corona infection. In the article, important terms such as different types of cases in corona infection, basic reproduction number, effective reproduction number, and their epidemiological significance in corona infection, herd immunity, and herd immunity threshold are discussed. The importance of lockdown as a preventive measure, enforcement of epidemic disease act 1897 and its amendment, disaster management act 2005, social distancing, cough etiquette, and others are highlighted.

Estimación del número reproductivo efectivo del brote de sarampión 2018-2019 en Chile / Estimation of the effective reproduction number of measles 2018-2019 in Chile

Resumen Introducción: Los casos de sarampión están resurgiendo en muchos países del mundo. Hubo un brote de sarampión importado entre noviembre de 2018 y febrero de 2019 en Chile, lo que generó preocupación entre el público y las autoridades sanitarias. Muchos se preocuparon por la tasa de inmunización contra el sarampión de la población, un factor que se relaciona con la capacidad reproductiva del virus (medida de transmisibilidad de un patógeno). Objetivo: Aquí estimamos el número reproductivo efectivo (Re) de este brote de sarampión. Resultados: Aunque la estimación tiene mucha incertidumbre por el bajo número de casos y la ausencia de mezcla homogénea de la población, encontramos que Re fue aproximadamente 1,5. Discusión y Conclusiones: En consecuencia estimamos que aproximadamente 90,3% de la población tiene inmunidad al sarampión, lo que coincide con las estimaciones del Ministerio de Salud. Estos resultados sugieren que la población chilena ha establecido la inmunidad colectiva contra la introducción de casos importados de sarampión, lo que refleja un manejo preventivo adecuado de esta enfermedad.

Abstract Background: Measles cases are reemerging in many countries across the globe. There was an outbreak of imported measles between November 2018 and February 2019 in Chile, raising concern among the public and health authorities. Many were worried about the Chilean measles herd immunity, a factor that relates to the reproductive capacity of the virus (measure of transmissibility of a pathogen). Aim: Here we estimate the effective reproductive number (Re) of this measles outbreak. Results: Although the estimate is highly uncertain due to the low number of cases and the absence of homogeneous mixing of the population, we found Re was approximately 1.5. Discussion and Conclusions: Consequently we estimated about 90,3 % had measles immunity, consistent with administrative estimates from the Ministry of Health. These results suggest the Chilean population has established herd immunity against the introduction of imported measles cases, reflecting adequate preventive management of this disease.

Fitting prediction of transmissibility and incidence trend of novel coronavirus pneumonia in Ningxia / 公共卫生与预防医学

Objective To analyze the change in transmissibility of novel coronavirus pneumonia and predict the trend of the incidence, and to provide a reference for the government to better respond to the novel coronavirus pneumonia epidemic. Methods The EpiEstimof R language software was used to estimate the change of effective basic reproduction number, and the Richards model was run by Matlab7.0 software to fit the cumulative number of confirmed cases and the number of suspected cases. The coefficient of determination and root mean squared error were used to evaluate the fitting effect of the model. Results A total of 75 confirmed cases and 107 suspected cases were reported in Ningxia. The strict implementation of various prevention and control measures gradually reduced the effective basic reproduction number from 3.82 to less than 1, indicating that the epidemic was under control. The Richards model was used to fit the cumulative confirmed cases and suspected cases, which revealed that the natural growth rates were 0.16 and 0.23, and the coefficients of determination were 0.991 and 0.998, respectively. Conclusion Combined with the effective basic reproduction number, the Richards model fitted the trend of novel coronavirus pneumonia, which can be used to predict the trend of incidence of new coronavirus pneumonia.