related_tweet: @anniejo196 @geezy_21z @hussellj @bebsdotter @thefreds @darrenmark69 "in the studied population, the risk of pre-symptomatic and asymptomatic transmission of covid-19 was low, with transmission risks of 1.12% and 0.06% respectively. pre-symptomatic infection becomes very rare in contacts made longer than 6 h before onset of symptoms. 1/2