11 There are two main routes by which people can spread COVID-19: • infection can be spread to people who are nearby (within 1 metre) by breathing in droplets coughed out or exhaled by a person with the COVID-19 virus; or • people may become infected by touching contaminated surfaces or objects (fomites) and then touching their eyes, nose or mouth (e.g. a person may touch a doorknob or shake hands and then touch their own face). This is why environmental disinfection is so important. According to current evidence, transmission may start just before symptoms become visible. However, many people infected with COVID-19 experience only mild symptoms. This is particularly true at the early stages of the disease. It is therefore possible to catch COVID-19 from someone who has, for example, just a mild cough and does not feel ill. WHO is assessing ongoing research on the period of transmission of COVID-19 and will continue to share updated findings. 7.4 How long can the virus survive on surfaces? How long any respiratory virus survives will depend on a number of factors, including: • • • • the type of surface the virus is on whether it is exposed to sunlight differences in temperature and humidity exposure to cleaning products. Under most circumstances, the amount of infectious virus on any contaminated surface is likely to have decreased significantly within 48 hours. Once such viruses are transferred to hands, they survive for very short lengths of time. Regular cleaning of hands and frequently touched hard surfaces with disinfectants will therefore help to reduce the risk of infection.