SARS-CoV-2 Transmission Dynamics in Mozambique and Zimbabwe During the First Three Years of the Pandemic

The 2019 emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its rapid spread created a public health emergency of international concern. However, the impact of the pandemic in Sub-Saharan Africa, as documented in cases, hospitalizations and deaths, appears far lower than in the Americas, Europe, and Asia. Characterization of the transmission dynamics is critical for understanding how SARS-CoV-2 spread and the true scale of the pandemic. Here, to better understand SARS-CoV-2 transmission dynamics in two southern African countries, Mozambique and Zimbabwe, we developed a dynamic model-Bayesian inference system to estimate key epidemiologic parameters, namely the transmission and ascertainment rates. Total infection burdens (reported and unreported) during the first three years of the pandemic were reconstructed using a model-inference approach. Transmission rates rose with each successive wave, which aligns with observations in other continents. Ascertainment rates were found to be low matching prior assumption and consistent with other African countries. Overall, the estimated disease burden was higher than the documented cases, indicating need for improved reporting and surveillance. These findings aid understanding of COVID-19 disease and respiratory virus transmission dynamics in two African countries little investigated to date, and can help guide future public health planning and control strategies.### Competing Interest StatementJeffrey Shaman and Columbia University disclose partial ownership of SK Analytics. All other authors have no conflicts of interest to disclose with regards to this study.### Funding StatementThis work was supported by US Centers for Disease Control and Prevention Contract 75D30122C14289 and US NIH Grant Al163023.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesI confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.YesThe data that supports the findings of this study are available upon request from INS Mozambique [Sergio Chicumbe -Directorate for health research, mailto:sergio.chicumbe@ins.gov.mz sergio.chicumbe@ins.gov.mz