Estimation of COVID-19 burden in Egypt

I 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.

Tuite and colleagues stated that they estimated the potential burden of coronavirus disease 2019 (COVID-19) in Egypt using the approach of Fraser and colleagues.² This approach was applicable to a scenario where abundant data were obtained from an epicentre of the H1N1 epidemic in Mexico in 2009, an approach that was disease and context specific. Although both viruses cause respiratory diseases and spread by contact and nose droplets, influenza has a shorter median incubation period than does severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Also, by contrast with influenza transmission, initial data for COVID-19 indicate that children are less affected than adults and that clinical attack rates in the 0–19 years age group are low. Fraser and colleagues used detailed H1N1 incidence data; by May 4, 2009, 11 356 suspected and 822 laboratory-confirmed cases had been reported in Mexico.2, 3, 4 By contrast, Tuite and colleagues based their conclusion on three reported cases in Egypt by March 6.¹ The scarcity of data available to the authors, as stated in their Correspondence, does not allow for the use of an appropriate modelling technique to estimate the burden of an epidemic.

Alternatively, Tuite and colleagues should have considered potential reasons for the low number of COVID-19 cases in Egypt, such as the considerable effort the Egyptian government has made to effectively control the outbreak. On March 25, a team of experts from WHO concluded a COVID-19 technical mission in Egypt. Yvan Hutin, director for communicable diseases in WHO's regional office and mission team lead, stated that “after several days of intensive meetings and field visits both inside and outside Cairo, we see that Egypt is making substantial efforts to control COVID-19 outbreak. Significant work is being done, especially in the areas of early detection, laboratory testing, isolation, contact tracing and referral of patients.” Hutin referred to the existing pattern of transmission as local rather than community and agreed with local authorities on additional measures to further slowdown COVID-19 spread.⁵ The report listed the various steps that have been made by the Egyptian Government—namely, allocating additional dedicated human and financial resources needed to contain the outbreak, expanding the number of peripheral laboratories that are able to test for SARS-CoV-2, and with support from WHO and other partners, increasing testing capacity (Egypt now has the capacity to do up to 200 000 tests).⁵ The report also commended Egypt's strong disease surveillance system and contact-tracing efforts as the main reasons behind the successful management of sporadic and clusters of cases before they spread.⁵

Another potential explanation for the low number of COVID-19 cases in Egypt is the mandatory—and free of charge—vaccination against tuberculosis with the BCG vaccine. The immune response-boosting effect of this vaccine has been postulated to potentially protect against SARS-CoV-2 infection, given that it has been shown to be effective against similar viruses. In March, a multicentre, phase 3, randomised clinical trial in Australia endorsed by WHO was fast tracked to investigate whether the BCG vaccine can protect against SARS-CoV-2.⁶ This trial aims to enrol 4000 health-care workers from hospitals in Australia in the next few weeks and should allow assessment of whether BCG vaccine can lessen the severity of COVID-19 symptoms.⁶

Finally, evolving data continue to support the slow spread of COVID-19 in Egypt. As of April 21, 2020, WHO estimates are of 3333 diagnosed cases in Egypt.⁷ These estimates continue to be carefully monitored, together with efforts taken to continue to slow down the spread of the disease.