Characterizing key attributes of the epidemiology of COVID-19 in China: Model-based estimations

Houssein H Ayoub; Hiam Chemaitelly; Ghina R Mumtaz; Shaheen Seedat; Susanne F Awad; Monia Makhoul; Laith J Abu-Raddad

The present study affirmed the impact and success of the drastic preventive measures in curtailing infection transmission. 0 R was sharply reduced by 97% over a short duration ( Figure 5 ). At the beginning of the epidemic, on average, each infected person had 0.6 infectious contacts per day, that is each person passed the infection to 0.6 persons per day ( Figure S2D of SI). The rate of infectious contacts can be expressed roughly as c p × , where c is the number of "social" contacts conducive to COVID-19 transmission per day and p is the transmission probability of the virus in a single contact. While p is unknown, it is possibly in the order of 1-5%, as suggested by contact tracing data from China-1-5% of contacts were subsequently laboratoryconfirmed as COVID-19 cases [3] . This implies that, on average, each infected person had somewhere between 10-60 contacts per day at the beginning of the epidemic, but very few contacts after the lockdown. The latter further affirms the role of the lockdown in severely cutting the contact rate, making sustainable infection transmission very difficult.