Factors associated with the spatial heterogeneity of the first wave of COVID-19 in France: a nationwide geo-epidemiological study

Cold and dry winter conditions are associated with greater SARS-CoV-2 transmission at regional level in western countries during the first epidemic wave

“…Countries in South West Europe and North America displayed low levels of preparedness and deployed no effective response before lockdowns. Still in these countries, SARS-CoV-2 virus spread heterogeneously at the regional level, as observed from hospitalization, death counts, and confirmed by serological surveys 3 , 4 , 37 .…”

Humoral immunity to SARS-CoV-2 and seasonal coronaviruses in children and adults in north-eastern France

“…SARS-CoV-2 infections occurred across the full age spectrum with higher seropositivity rates in adults and adolescents compared with children. Higher seroprevalence estimates were also observed in heavily affected areas during the first wave in France [30], and samples collected further in the year, reflecting the progression of the epidemic [31]. Within positive classified samples, the immune response to several antigens is lower in adolescents and young adults compared to young children and older adults.…”

“…There has been much discussion regarding the potential role of cross-protective immunity to SARS-CoV-2 infection due to previous seasonal HCoV infection [20,22,24,30], similar to the recently reported interaction between rhinovirus and influenza virus [39]. A detailed understanding of cross-protection of coronaviruses requires appropriately designed studies, such as longitudinal cohorts or experimental infection studies, ideally with assessment of both humoral and cellular immunity.…”

“…Seroprevalence estimates are highly dependent on recruitment strategies and should be interpreted carefully as participants, of whom we had limited data, were recruited through residual serum sampling of non-COVID-19 patients in hospitals of which some were located in heavily affected areas of France [30,31]. We did not have data on the medical status of patients whom provided serum samples and therefore limited insight into potential biases.…”

Inter-regional transfers for pandemic surges were associated with reduced mortality rates

“…The spread of the coronavirus disease 2019 (COVID-19) pandemic has shown important spatial heterogeneity of in-hospital COVID-19 cases and deaths between countries and regions. Across metropolitan France, the healthcare system has been overwhelmed by the pandemic surge unequally over the regions, leading to the inability to provide care in areas with outpaced resources [ 1 , 2 ]. In response, mass inter-regional transfers of critically ill patients have been organized.…”