Coronaviruses primarily affect the upper respiratory tract in humans. They are transmitted through respiratory droplets. Being close to infected persons who sneeze or cough, even speak loudly can infect someone. Even touching surfaces where the viruses have been deposited can infect a person. The virus is viable for the period that it remains on the surface and is capable of spreading infection.
A study was published in The New England Journal of Medicine on the viability of SARS-CoV-2. It found that SARS-CoV-2 was detectable in aerosols for up to three hours. On copper, it was detectable up to four hours. It was detectable up to 24 hours on cardboard. On plastic and stainless steel, it was detectable the longest — up to two to three days. The study also found that the risk of getting infected reduces with every passing minute.
Scientists say viruses are not capable of multiplying by themselves without a host. But SARS-CoV-2 may remain viable for hours to days on surfaces. Therefore disinfection helps in reducing the viral load in the environment. A 1 % hypochlorite solution is an effective disinfectant on various surfaces. Floors, walls and surfaces frequently touched by hands should be disinfected.
According to CDC, it is unknown how long the air inside a room occupied by someone with COVID-19 remains potentially infectious. Therefore it is important to take measures to improve ventilation in an area or room where someone was ill or suspected to be ill. This will help shorten the time it takes respiratory droplets to be removed from the air.
Also read: What have scientists observed about the novel coronavirus?