Reconstructing the global dynamics of unreported COVID-19 cases and infections

Status: Paper under peer review | First online: 07-07-2020 | Last update: 07-07-2020

This study has not yet been peer reviewed.

Read the full preprint here.

**Figure 2: Confirmed case curves adjusted for temporal under-ascertainment. Panel A: Confirmed cases (left) and adjusted cases (right) for the ten countries with the highest number of confirmed cases. Panel B: Confirmed cases (left) and adjusted cases (right) for the ten countries with the highest number of confirmed cases after adjusting for under-ascertainment. There are two countries which change between panels A and B: France and Mexico are replaced by Chile and Peru respectively. Panel C: The same curves plotted in panel A, but with a plot per country. Blue shaded region corresponds to the 95% CrI of the adjusted curves. Panels A and B highlight between country variation whereas panel C highlights within country variation.


Methods: Using reported data on COVID-19 cases and fatalities globally, we estimated the proportion of symptomatic cases (i.e. any person with any of fever >= 37.5°C, cough, shortness of breath, sudden onset of anosmia, ageusia or dysgeusia illness) that were reported in 210 countries and territories, given those countries had experienced more than ten deaths. We used published estimates of the baseline case fatality ratio (CFR), which was adjusted for delays and under-ascertainment, then calculated the ratio of this baseline CFR to an estimated local delay-adjusted CFR to estimate the level of under-ascertainment in a particular location. We then fit a Bayesian Gaussian process model to estimate the temporal pattern of under-ascertainment.

