Among 128 people who tested positive for Covid-19 during an outbreak on an Antarctic cruise, how many of them ultimately had no symptoms?
In one of the few cases where asymptomatic cases could be reliably counted because an entire population was tested for C-19, the journal BMJ Thorax published a study in May about an outbreak of C-19 on an Antarctic cruise. In this case, everyone onboard "had no outside human contact" for 28 days, the passengers were quarantined in their rooms on the 8th day of the cruise, the crew wore personal protective equipment thereafter, and everyone was tested for C-19 on day 20. Among the 128 people who tested positive, 81% ultimately had no symptoms, 13% had mild symptoms, and 6% had serious symptoms, including one that died. This study is consistent with others that have examined the asymptomatic rate.