Descriptive Epidemiological Assessment of the Relationship between the Global Burden of Influenza from 2017-2019 and COVID-19

Abstract

<jats:p>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.</jats:p>

Leveraging epidemiological principles to evaluate Sweden’s COVID-19 response

“…While Sweden’s approach has often been described as passive or “laissez-faire”, risk-adaptive approaches actually require greater effort from public health authorities with rapid identification of determinants of infection, development and implementation of specific interventions, as compared to implementing blunt population-wide mandates( 9 ). With the arrival of autumn, SARS-CoV-2 has returned to Europe along with most Northern climates as was generally predicted given the seasonal nature of similar lipid-enveloped viruses( 62 ). The resurgence in COVID-19 cases in many countries has led to re-implementation of restrictions including broad lockdown mandates being termed “circuit-breakers” or “fire break”.…”

“…In contrast, in a the Spanish National Seroprevalence Survey of 61,000 participants , those over 65 were most likely to have antibodies with 6.0% (>65), compared to 5.3% ( 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53. ( , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ), and 3.4% (0-19)( 20 ) . Among other countries, Iran and Japan had similar age-distribution as observed in Spain, while Switzerland reported estimates more like Sweden ( 21 , 22 , 23 ).…”