According to an epidemiological model published by Science , under 80 % of reported cases of coronavirus were caused by undocumented infections .
However , an epidemiological model of the beginning of the outbreak in China ( published in Science ) suggested that `` pre-symptomatic shedding may be typical among documented infections '' and `` undocumented infections were the infection source for 79 % of documented cases '' .
Severe acute respiratory syndrome coronavirus 2