Open Access Open Access  Restricted Access Subscription or Fee Access

A COVID-19 time-dependent SIRD model using functional differential equations

Edson A. Coayla-Teran


In this paper we develop a mathematical model for the spread of the coronavirus disease 2019 (COVID-19) with the goal to do forecasts for the number of infected, recovered and deceased individuals. To do this, we propose a SIRD model, which takes into account the fact that susceptible individuals that meet infected individuals are not immediately infected, they become infected after a period. Similarly, infected individuals recovered or deceased not immediately but after a period which is denoted. These considerations produce discrete delays in the classic SIRD model which is a particular case of functional differential equations. Furthermore, to take into account the effect of the social distancing, mask use or other actions to reduce the risk of infectivity, we consider that the transmission, the recovery and the death rates are not constants but time-dependent. To apply the model proposed, we developed an algorithm which uses ridge regression to do forecasts for the Peruvian regions of Moquegua and Tacna.


Covid-19, SIRD model, Functional differential equations, Ridge regression.

Full Text:


Disclaimer/Regarding indexing issue:

We have provided the online access of all issues and papers to the indexing agencies (as given on journal web site). It’s depend on indexing agencies when, how and what manner they can index or not. Hence, we like to inform that on the basis of earlier indexing, we can’t predict the today or future indexing policy of third party (i.e. indexing agencies) as they have right to discontinue any journal at any time without prior information to the journal. So, please neither sends any question nor expects any answer from us on the behalf of third party i.e. indexing agencies.Hence, we will not issue any certificate or letter for indexing issue. Our role is just to provide the online access to them. So we do properly this and one can visit indexing agencies website to get the authentic information. Also: DOI is paid service which provided by a third party. We never mentioned that we go for this for our any journal. However, journal have no objection if author go directly for this paid DOI service.