CoronaSurveys: Using Surveys with Indirect Reporting to Estimate the Incidence and Evolution of Epidemics

Ojo, Oluwasegun; Garc'ia-Agundez, Augusto; Girault, Benjamin; Hern'andez, Harold; Cabana, Elisa; Garc'ia-Garc'ia, Amanda; Arabshahi, Payman; Baquero, Carlos; Casari, Paolo; Ferreira, Ednaldo Jos'e; Frey, Davide; Georgiou, Chryssis; Goessens, Mathieu; Ishchenko, Anna; Jim'enez, Ernesto; Kebkal, Oleksiy; Lillo, Rosa; Menezes, Raquel; Nicolaou, Nicolas; Ortega, Antonio; Patras, Paul; Roberts, Julian C; Stavrakis, Efstathios; Tanaka, Yuichi; Anta, Antonio Fern'andez

The world is suffering from a pandemic called COVID-19, caused by the SARS-CoV-2 virus. National governments have problems evaluating the reach of the epidemic, due to having limited resources and tests at their disposal. This problem is especially acute in low and middle-income countries (LMICs). Hence, any simple, cheap and flexible means of evaluating the incidence and evolution of the epidemic in a given country with a reasonable level of accuracy is useful. In this paper, we propose a technique based on (anonymous) surveys in which participants report on the health status of their contacts. This indirect reporting technique, known in the literature as network scale-up method, preserves the privacy of the participants and their contacts, and collects information from a larger fraction of the population (as compared to individual surveys). This technique has been deployed in the CoronaSurveys project, which has been collecting reports for the COVID-19 pandemic for more than two months. Results obtained by CoronaSurveys show the power and flexibility of the approach, suggesting that it could be an inexpensive and powerful tool for LMICs.