Coronavirus spread from asymptomatic people appears to be rare: WHO
During a press briefing in Geneva, Maria Van Kerkhove mentioned that as per the WHO's data, it still seems to be rare that an asymptomatic person can actually transmit the virus to the second individual.
Maria Van Kerkhove, the World Health Organization’s technical lead for Coronavirus response and head of the emerging diseases, has stated that the spread of COVID-19 by those who do not show any symptoms of being infected by the virus, seems to be rare.
During a press briefing in Geneva on June 8, Maria Van Kerkhove mentioned that from the data that WHO has, it still seems to be rare that an asymptomatic person can actually transmit the virus to the second individual.
The technical lead of the Coronavirus response also informed that the data also shows that what appears to be an asymptomatic case of COVID-19, they often turn out to be the cases of mild diseases.
Statement by Maria Van Kerkhove:
During her address, Maria Van Kerkhove informed that there are a number of reports from countries that have been doing very detailed contact tracing. They have been following the asymptomatic cases, they have been following the contacts and have not found any second transmission onward. She further added that it is very rare and much of that has not been published in the literature.
She mentioned that the WHO has been constantly looking at this data and have been trying to get more information from countries to truly answer the question. But it still appears to be rare that an asymptomatic individual can actually transmit onwards.
Kerkhove also said that when we actually go back and say how many of them were truly asymptomatic, we found that many have really mild diseases. They are not, in particular, COVID symptoms which means they may not have developed fever yet or they may not have shortness of breath or they may not have had a significant cough- but some may have mild disease. While stating this, she mentioned that we do not know that there are people who can be truly asymptomatic.
What is the difference between asymptomatic and pre-symptomatic?
Dr. Manisha Juthani, an infectious disease specialist and an associate professor of medicine and epidemiology at Yale School of Medicine explained that pre-symptomatic refers to the early stages of illness before the symptoms have developed while asymptomatic may refer of having no symptoms throughout the course of infection. This distinction was also hinted by Maria Van Kerkhove during her address.
Dr. Juthani further added that many people with COVID-19 who appear to be asymptomatic could actually just have mild or atypical symptoms- or they could be pre-symptomatic.
A study done in April 2020 found that viral shedding- when people can infect others- can begin two to three before the symptoms appeared. The US Centres for Disease Control and Prevention has estimated in planning scenarios that 40 percent of COVID-19 transmission has been occurring before people feel sick.
Dr. Juthani added that these patients were not asymptomatic instead they were spreading diseases before becoming symptomatic. She further informs that these findings suggest that if we quarantine and contact trace symptomatic people, there can be a significant dent in the pandemic.