Fig. 1.

Cycles threshold (Ct) value for SARS-CoV-2 strains. Median estimates based on the linear model are shown in the box plot, and number of tests in each class are shown in the bottom of the graph. ‘other’ indicate tests with the $\Delta$69-70 deletion and without the N501Y mutation. Start indicate the significance level ($****$ for a p-values strictly lower than ${10}^{-4}$ and $***$ for a p-value of ${10}^{-4}$, ns: not significant).