How to Limit the Indoor Transmission of COVID-19 from Asymptomatic Patients

Most patients with Covid-19 can be infectious about two days before they develop symptoms. Some patients who never show any symptoms can still infect others before their recovery. The transmission during both asymptomatic periods is hard to detect.
As asymptomatic patients hardly cough or sneeze, their spread of the virus should be through talking, breathing and singing. Since most of Covid-19 infection has spread from person to person indoors, some recommendations for indoor activities would be:
1. Less talking. The purpose of talking can be achieved mostly by exchanging text on smartphones, computers or a piece of paper.
2. Safe breathing. As physical activities will greatly increase our breath rate, indoor exercise should be accompanied with good ventilation to avoid airborne transmission.
3. Less singing. Singing in unison is not recommended for the airborne reason. People could sing in silence rather than in voice. If making sounds is necessary then make a record safely in advance and play it at the place where singing is required.