New research suggests that asymptomatic or pre-symptomatic COVID-19 cases are driving the spread.
Scientists have found that silent transmission could be responsible for half of COVID-19 cases.
The study, published in the Proceedings of the National Academy of Sciences, found that more than one-third of these infections would need to be identified and isolated to prevent a future outbreak.
Researchers said even immediate isolation of all symptomatic cases would not be enough to get the coronavirus under control.
The model assumed that COVID-19 may be the most contagious during the pre-symptomatic stage, which is uncommon for a respiratory infection.