감염자와 밀접하게 접촉하지 않아도 어딘가에 묻어 있던 바이러스를 손으로 만졌다가 입·코 등을 손으로 만지면서 감염되기 때문이다.
This is because the virus that was buried somewhere is infected by touching the mouth and nose with hands even if it is not in close contact with the infected person.