In this modelling analysis of presymptomatic infectiousness,
our model suggested that infectiousness
might begin 0.4 days (95% CrI: − 1.2 to 2.4) before illness
onset, which corresponded to a very small (right)
shift from the prior distribution. Hence, there was no
evidence that infectiousness preceded symptom onset.
The same conclusion remained when the standard
deviation of the prior was halved or doubled.