Evaluating the impact of curfews and other measures on SARS-CoV-2 transmission in French Guiana (preprint)

While general lockdowns have proven effective to control SARS-CoV-2 epidemics, they come with enormous costs for society. It is therefore essential to identify control strategies with lower social and economic impact. Here, we report and evaluate the control strategy implemented during a large SARS-CoV-2 epidemic in June-July 2020 in French Guiana that relied on curfews, targeted lockdowns and other measures. We find that the combination of these interventions reduced the basic reproduction number of SARS-CoV-2 from 1.7 to 1.1, which was sufficient to avoid saturation of hospitals. We estimate that thanks to the young demographics across the territory, the risk of hospitalisation following infection was 0.3 times that of metropolitan France and that about 20% of the population was infected by July. Our model projections are consistent with a recent seroprevalence study. The study showcases how mathematical modeling can be used to support healthcare planning and decision making in a context of high uncertainty.

Seroprevalence of anti-SARS-CoV-2 IgG at the epidemic peak in French Guiana (preprint)

Background SARS-CoV-2 seroprevalence studies are crucial for clarifying dynamics in affected countries and determining the route that has already been achieved towards herd immunity. While Latin America has been heavily affected by the pandemic, only a few seroprevalence studies have been conducted there. Methods A cross-sectional survey was performed between 15 July 2020 and 23 July 2020 in 4 medical biology laboratories and 5 health centers of French Guiana, representing a period shortly after the epidemic peak. Samples were screened for the presence of anti-SARS-CoV-2 IgG directed against domain S1 of the SARS-CoV-2 spike protein using the anti-SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) from Euroimmun. Results The overall seroprevalence was 15.4% [9.3%-24.4%] among 480 participants, ranging from 4.0% to 25.5% across the different municipalities. The seroprevalence did not differ according to gender (p=0.19) or age (p=0.51). Among SARS-CoV-2 positive individuals, we found that 24.6% [11.5%-45.2%] reported symptoms consistent with COVID-19. Conclusions Our findings revealed high levels of infection across the territory but a low number of resulting deaths, which can be explained by the young population structure.