Estimation of COVID-19 burden in Egypt – Authors' reply
Authors: Ashleigh R Tuite, Victoria Ng, Erin Rees, David Fisman, Annelies Wilder-Smith, Kamran Khan, Isaac I Bogoch
Journal: The Lancet Infectious Diseases (2020)

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,1WHOCoronavirus disease (COVID-2019) situation reports.https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reportsDate accessed: April 13, 2020Google Scholar 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 models2Centre for Mathematical Modelling of Infectious DiseasesInferring COVID-19 cases from deaths of confirmed cases. London School of Hygiene and Tropical Medicine.https://cmmid.github.io/visualisations/inferring-covid19-cases-from-deathsDate: 2020Date accessed: April 13, 2020Google Scholar 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-19.3Zhou F Yu T Du R et al.Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study.Lancet. 2020; 395: 1054-1062Summary Full Text Full Text PDF PubMed Scopus (18730) Google Scholar Egypt's median age is approximately 25 years,4WHOGlobal Health Observatory data repository.https://apps.who.int/gho/data/view.main.POP2040?lang=enDate accessed: April 13, 2020Google Scholar 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. KK is the founder and CEO of BlueDot. IIB has consulted for BlueDot. All other authors declare no competing interests. Estimation of COVID-19 burden in EgyptThe foundation of any estimation process is the use of independent unbiased samples. However, when attempting to estimate Egypt's burden of coronavirus disease 2019 (COVID-19) by studying exported cases, Ashleigh Tuite and colleagues1 established neither independence nor absence of bias for the cases used in their study. This approach is especially problematic in the light of widespread news of a tourist cruise ship in Egypt exporting COVID-19 across the world through hundreds of tourists who were onboard during the timeframe used by Tuite and colleagues in their Correspondence. Full-Text PDF Estimation of COVID-19 burden in EgyptI read with interest the Correspondence by Ashleigh Tuite and colleagues,1 and I respectfully disagree with the methods used by the authors and their conclusion. Full-Text PDF Estimation of COVID-19 burden in EgyptTo estimate the burden of coronavirus disease 2019 (COVID-19) in Egypt, Ashleigh R Tuite and colleagues1 used the same model of exported case detection used by Fraser and colleagues for the H1N1 outbreak in Mexico.2 However, Tuite and colleagues neither clarified nor verified the assumptions of this exported case-detection model. First, the authors used data from the UN World Tourism Organization (UNWTO) on the average length of stay in Egypt by tourists (11·6 days), which is not accurate for the following reasons: we contacted UNWTO to verify the most recent estimates, and the average length of stay by tourists in Egypt was 11·6 days in 2018, 7·78 days in 2017, 6·1 days in 2016, 9 days in 2015, and 10 days in 2014, with no estimates available for February, 2020; the UNWTO estimates combine the length of stays of domestic and international tourists, including visitors from several countries other than the USA, Canada, France, and Taiwan; and for Egypt, a country with rapid changes in the political, economic, and tourism fields, it would be inaccurate to confidently consider these incomplete statistical data for the present model of February, 2020. Full-Text PDF Estimation of COVID-19 burden in EgyptWe read with interest the Correspondence by Ashleigh Tuite and colleagues.1 We thank them for their interest in estimating the coronavirus disease 2019 (COVID-19) burden in Egypt. However, their model-based calculations used the number of patients known on March 6, and the numbers of patients and deaths are continuously changing. Attempting to reach a more up-to-date estimate of the expected number of patients in Egypt, we used other assumptions according to real-life data. Full-Text PDF