New Information About How COVID-19 Is Spread from Person to Person

On April 2 the WHO published a summary of recent data analysis concerning transmission of COVID-19. This information is evidenced-based and trustworthy.

Symptomatic transmission is when the coronavirus is spread from one sick person to another person in close contact through respiratory droplets, or by contact with contaminated objects and surfaces. This is the MOST COMMON way that COVID-19 is spread.

There is also evidence that the virus is most contagious from the nose and throat early in the illness — in the first 3 days from the start of symptoms. This means that the virus is easier to spread at the beginning of symptoms, rather than after the person has been sick for a few days.

Pre-symptomatic transmission is when the virus is spread during the incubation period. This is the time between becoming infected with the virus and showing symptoms of the virus. The incubation period for COVID-19 is 2-14 days, and the average is 5-6 days. There are a small number of cases when some people can test positive for the virus 1-3 days before they develop symptoms. So it is possible that people infected with COVID-19 could transmit the virus before significant symptoms develop. But the way the virus transmits is still the same: through infectious droplets or through touching contaminated surfaces.

Asymptomatic transmission is when the virus spreads from a person who tested positive for COVID-19 but never developed symptoms. There are very few reports of laboratory-confirmed cases who truly have no symptoms. And to date, there are no cases of asymptomatic transmission.

Here is the link to the original article by WHO, including references to all the studies.