How is COVID-19 Transmitted?
Q&A by the World Health Organization
By now, it's common knowledge that the coronavirus can be spread by being in close contact with someone who's infected and then breathing in their respiratory droplets. Or by touching a contaminated surface and rubbing your eyes, nose or mouth.
An open letter signed by 239 researchers addressed to the World Health Organization, published on 6 July 2020 in Clinical Infectious Diseases, called for attention and guidance around a third route of transmission: tiny respiratory particles that float in the air and are called aerosols and that, the researchers state, could be responsible for infecting someone who comes along and breathes them in.
The World Health Organization (WHO) on 9 July issued new guidelines on the transmission of the novel coronavirus acknowledging these reports of airborne spread of the SARS-CoV-2 virus that causes COVID-19.
In continuation of which WHO released the Q&A on their website which are as below:
Q. How does Coronavirus most commonly transmitted between people?
A. Direct, indirect (through contaminated objects or surfaces), or close contact with infected people via mouth and nose secretions.
People who are in close contact (within 1 metre) with an infected person can catch COVID-19 when those infectious droplets get into their mouth, nose or eyes.
Q. What are the other ways in which the COVID-19 virus could be transmitted?
A. Infected people can leave droplets on objects and surfaces (called fomites) when they sneeze, cough on, or touch surfaces. Other people may become infected by touching these objects or surfaces, then touching their eyes, noses or mouths
Q. What do we know about aerosol transmission?
A. Aerosol generating medical procedures can produce very small droplets that are able to stay suspended in the air for longer periods of time. These aerosols from an infected patient may potentially be inhaled by others if they are not wearing appropriate personal protective equipment (PPE).
Aerosol transmission cannot be ruled out where there are outbreaks of COVID-19 in some closed settings, such as restaurants, nightclubs, places of worship, which are crowded and inadequately ventilated spaces where infected persons spend long periods of time with others.
Q. When can infected people transmit the virus?
A. Primarily transmits from people when they have symptoms, or just before they develop symptoms. While someone who never develops symptoms can also pass the virus to others, it is still not clear to what extent this occurs and more research is needed in this area.
Q. Can people without symptoms transmit the virus?
A. Yes, infected people can transmit the virus both when they have symptoms and when they don’t have symptoms. This is why it is important to identify all infected people by testing, isolated, and receive medical care.
Q. What is the difference between people who are asymptomatic or pre-symptomatic? Don’t they both mean someone without symptoms?
A. Yes, both terms refer to people who do not have symptoms.
Difference is asymptomatic refers to people who are infected but never develop symptoms during the period of infection while pre-symptomatic refers to infected people who have not yet developed symptoms but do go on to develop symptoms later
Q. What does WHO recommend in order to prevent COVID-19?
A. Health workers should use medical masks continuously during all routine activities in clinical areas. They should also use additional personal protective equipment and precautions when caring for COVID-19 patients. More details are available here and here.