Letter on the article Modeling the Transmission Dynamics of COVID-19 | CLEP

Dear editor

We read Jemal and Alemu’s article,¹ in which they presented their modeling of the COVID-19 transmission dynamics in the five African countries including: South Africa, Morocco, Tunisia, Ethiopia and Libya. We congratulate the author on his work. At the same time, we would like to share our outlook on the study out of concern about some factors that might lead to deviations from reality regarding the results and their interpretations of the model.

The authors said that on February 7, 2022, the SARS-CoV-2 virus spread to 58 African countries. South Africa was considered the continent’s hardest-hit country with over 3 million cases and over 95,000 deaths and a simple reproduction number (R₀) from 7.02. South Africa has reportedly been subjected to strict COVID-19 prevention control measures, including the government’s call for a National State of Disaster, lockdowns and travel bans.² In comparison, in March 2022 in Pakistan, the National Command and Operation Center (NCOC) declared that COVID-19 had returned to normal after infecting over 1 million and causing over 30,000 deaths and therefore lifted all restrictions.³ The R₀ reported for Pakistan was approximately 1.05.⁴ Lessons to be learned from Pakistan’s response to the pandemic include both full and smart lockdowns, awareness campaigns, quarantines and contact tracing, and organizing screening camps with mass testing.⁴

The authors shared that the host’s defensive response to the virus is influenced by vaccination against SARS-CoV-2, the presence of comorbidities, age and previous infection. In addition, nutritional status is also an important factor in host immune response, which is even more important as African nations are plagued by poverty.

In the SIMCR model, the authors considered the vulnerable and the infected groups. Asymptomatic cases of COVID-19 can also be considered virus carriers while infected and may miss the diagnosis of COVID-19 infection as they may have almost no symptoms. Therefore, according to this model, the place of the asymptomatic cases is ambiguous.

The authors concluded that by vaccinating half of the African population, living particularly in South Africa, Morocco, Tunisia, Ethiopia and Libya, in 30 years about 17 million of them would be protected from COVID-19 infection and millions lives can be saved. However, a number of African countries have been reported to be suffering from an outbreak of measles infection, raising concern as measles can erase the memory of immunity gained from vaccination against COVID-19.⁵ Therefore, thorough consideration and appropriate measures in this direction are warranted to effectively contain the pandemic.

A model of the transmission dynamics of COVID-19 is always needed to alert and warn of the rising number of infections. In summary, it is our responsibility to interpret the results of the models wisely and carefully, and to rigorously implement the most comprehensive and intelligent measures necessary to prevent unintended and avoidable harm in a country like Africa.

disclosure

The authors report no conflicts of interest in this communication.

references

1. Jemal SS, Alemu BD. Modeling the dynamics of transmission of COVID-19 between five African countries with high burden. Clin Epidemiol. 2022;14:1013-1029. doi:10.2147/CLEP.S366142

2. Goitom H. Actions taken by the South African government to contain the spread of COVID-19 and mitigate harm. Library of Congress; 2020. Available at: https://blogs.loc.gov/law/2020/04/south-africa-government-measures-to-contain-the-spread-of-covid-19-and-mitigate-damages/. Accessed September 222022.

3. Junaidi I Curtain falls on NCOC as nation looks beyond Covid. DUSK; 2022. Available at: https://www.dawn.com/news/1682861/curtain-falls-on-ncoc-as-nation-looks-beyond-covid. Accessed September 222022.

4. Taimoor M, Ali S, Shah I, Muwanika FR. COVID-19 pandemic data modeling in Pakistan using time-series SIR. Calculation of mathematical methods Med. 2022;2022:6001876. doi:10.1155/2022/6001876

5. Guglielmi G. Measles erases the immune system’s “memory” for other diseases [published online ahead of print, 2019 Oct 31]. Nature. 2019. doi:10.1038/d41586-019-03324-7