asymptomatic person; person without symptoms
Primarily used in medical and public health contexts for someone infected but not showing symptoms.
Even asymptomatic people can spread the virus.
感染者 is a broader term for any infected person, while 無症状者 specifically refers to those without symptoms.
有症状者 is the opposite, meaning a symptomatic person.
Compound of 無 (mu, 'without'), 症状 (shōjō, 'symptom'), and 者 (sha, 'person').