Analysis of excess deaths from COVID-19 in El Salvador through time series

The databases of deaths in El Salvador are analyzed for the years from 2015 to 2020. From these databases, the monthly time series of the number of deaths per month is constructed for the aforementioned years, treating the following five cases: Death from kidney disease, death from some type of failure (heart attack, respiratory failure, cardiorespiratory failure), death from cancer, death from causes other than firearms or traffic accidents (causes that are considered to have suffered intervention in 2020 due to the mandatory quarantine that was imposed), finally a model that includes all causes of death is considered. Time series models are adjusted, in each case, to predict the months of the year 2020. These forecasts are compared with real cases and the underreporting of deaths from COVID-19 is measured according to official data. In each case, two models are adjusted: Box–Jenkins Method (Seasonal Autoregressive Integrated Moving Average, SARIMA) and Holt-Winters Additive Method (it is optimized with a developed heuristic). This work shows that there are many people who really died from COVID-19, but the official record lists them in other cases. In such a way that there is high statistical evidence of under-registration from official data provided by the government on deaths from COVID-19, in the period covered by this study.