How can 'asymptomatic' COVID-19 cases be contagious? Expert explains

Health Secretary Francisco Duque III recently told senators that there is still no evidence that asymptomatic cases can infect others with the coronavirus disease (COVID-19).

This, however, does not necessarily mean that a person who has no symptoms is not capable of transmitting the virus to another individual.

"Wala pang ebidensiya na nakaka-transmit 'yon pero hindi ibig sabihin na hindi sila nakaka-transmit," said Dr. Edsel Salvaña, the director of the UP Institute of Molecular Biology and Biotechnology.

In an episode of "Stand for Truth," he also clarified that there is a difference between "asymptomatic" and "presymptomatic" cases.

An asymptomatic case refers to a person who carries the active virus in the body but never develop any symptoms, while a presymptomatic case refers to a person who has been infected but does not show any symptoms yet.

"Hindi pa sila nagkakaroon ng sintomas, nagsisimula na silang mag-shed ng virus at puwedeng makahawa 'yung virus na 'yun," Salvaña said.

The time between between exposure to the virus and onset of symptoms is called the incubation period, according to the World Health Organization. This can last up to 14 days.

According to Salvaña, presymptomatic cases are not as efficient in spreading the virus, but they are still responsible for about 12 to 15 percent of virus transmissions. Symptomatic cases, meanwhile, are responsible for 85 percent.

"Kasi 'yung taong may sintomas, bumabahing 'yan, umuubo 'yan, so nagtatalsik talaga 'yung respiratory droplet," he said.

This is why wearing facemasks, proper handwashing and stopping oneself from touching the eyes, nose and mouth are important.

"'Yung virus, pag bumahing at nasinghot mo, wala. Game over na 'yun," Salvaña said. —Margaret Claire Layug/MGP, GMA News