Estimation of COVID-19 burden in Egypt – Authors' reply

We thank Mohamed Hassany and colleagues, Ahmed Negida, Tarek Sahmoud, and Khaled Elmeleegy for raising their concerns about our modelling study. We would like to reiterate that the number of confirmed cases of coronavirus disease 2019 (COVID-19) in every country worldwide (Egypt included) is an underestimate of the true burden of illness, regardless of the screening programmes in place. Although we are aware that all modelling studies have limitations, we believe that it is important to rely on multiple sources of information to have a more accurate reflection of the so-called ground truth. For example, as of April 12, 2020, Egypt has reported 146 COVID-19-related deaths,¹ and as with reported cases, reported deaths are also an underestimate of the true value. By use of mortality data (both retrospectively and in real-time), other models² have corroborated our findings and still predict a much larger outbreak than that currently reported in Egypt. Interestingly, Egypt's age demographics might contribute to fewer detected cases than those in other countries. There is a growing understanding that individuals older than 60 years are disproportionally affected by COVID-19.³ Egypt's median age is approximately 25 years,⁴ so more subclinical cases are likely to exist in Egypt compared with other parts of the world.

We appreciate that many reasons exist for why reported case numbers are lower than the true values, including a country's capacity to detect or report such data. We would like to reiterate that models that predict the burden of illness do not carry value judgment and are apolitical; however, they might help understand infection patterns and shape meaningful public health responses.