The Relationship between the Global Burden of Influenza from 2017-2019 and COVID-19

Baral, S. D.; Rucinski, K. B.; Twahirwa Rwema, J. O.; Rao, A.; Prata Menezes, N.; Diouf, D.; Kamarulzaman, A.; Phaswana-Mafuya, N.; Mishra, S.

Background SARS-CoV-2 and Influenza are lipid-enveloped viruses with differential morbidity and mortality but shared modes of transmission. We assessed whether historical patterns of regional influenza burden are reflected in the observed heterogeneity in COVID-19 cases across and within regions of the world. Methods Weekly surveillance data reported in FluNet from January 2017-December 2019 for influenza and World Health Organization for COVID-19 (to May 31, 2020) across the seven World Bank regions were used to assess the total and annual number of influenza and COVID-19 cases per country, within and across all regions, to generate comparative descending ranks from highest to lowest burden of disease. Results Across and within regions, rankings of influenza and COVID-19 were relatively consistent. Europe and Central Asia and North America ranked first and second for COVID-19 and second and first for influenza, respectively. East Asia and the Pacific traditionally ranked higher for influenza but to date, has been less affected by COVID-19. Between regions, Sub-Saharan Africa ranked amongst the least affected by both influenza and COVID-19. Conclusion Consistency in distribution of the burden of COVID-19 and influenza suggest shared individual, structural, and environmental determinants of transmission. Regions with discrepancies between influenza and COVID-19 burden may provide further insight into the potential impact of non-pharmacologic interventions and intersections with environmental conditions. Ultimately, forecasting trends and informing interventions for novel respiratory pathogens like COVID-19 should leverage patterns in the relative burden of past respiratory pathogens and the relative impact of non-pharmacologic intervention strategies as prior information.