  The infectivity profile of an individual with COVID-19 is attributed to the
paper Temporal dynamics in viral shedding and transmissibility of COVID-19 by
He et al., published in Nature Medicine in April 2020. However, the analysis
within this paper contains a mistake such that the published infectivity
profile is incorrect and the conclusion that infectiousness begins 2.3 days
before symptom onset is no longer supported. In this document we discuss the
error and compute the correct infectivity profile. We also establish confidence
intervals on this profile, quantify the difference between the published and
the corrected profiles, and discuss an issue of normalisation when fitting
serial interval data. This infectivity profile plays a central role in policy
and decision making, thus it is crucial that this issue is corrected with the
utmost urgency to prevent the propagation of this error into further studies
and policies. We hope that this preprint will reach all researchers and policy
makers who are using the incorrect infectivity profile to inform their work.
