Can COVID-positive persons infect others even if they don't show symptoms?

Health Secretary Francisco Duque III triggered an online debate when he proclaimed that there is still no evidence that COVID-19-positive people can infect others if they're asymptomatic.

But according to the World Health Organization (WHO), it might still possible for positive patients to infect others even if they show no symptoms.

How exactly is the virus transmitted from symptomatic, pre-symptomatic or asymptomatic cases?

1. Symptomatic cases

Symptomatic transmission occurs when an individual showing symptoms of COVID-19 infects other people.

Such symptoms are coughs, fever and difficulty in breathing. WHO shared that there is evidence that the virus can be transmitted from symptomatic people to others who are in close contact through respiratory droplets; by direct contact like touching; or by contact with objects and surfaces the infected person touched.

WHO said that the viral shedding, or the spread of the virus in the nose and throat, is highest during the first three days the symptoms appear.

There is also the higher chance that a COVID-19 patient would infect others when the symptoms start to appear compared to when later on in the disease.

2. Pre-symptomatic cases

Transmission can also occur during the "pre-symptomatic period."

This period, also known as the incubation period of COVID-19, happens between the time you're exposed to the virus and when the symptom appears. This happens on an average of five to six days but can occur up to 14 days.

Even if symptoms do not persist just yet, an infected person can still be contagious and spread the virus.

3. Asymptomatic cases

An asymptomatic laboratory-confirmed case is an individual who is positive with COVID-19 and yet does not show any symptoms.

WHO said that there are only a few reports of people who are truly asymptomatic and that there has been no documented asymptomatic transmission to date.

However, it said that it might still possible to infect other people despite being asymptomatic, so best to err on the side of caution.

Some countries continue to include asymptomatic cases as part of their contact tracing efforts.

Since declaring the novel coronavirus a pandemic, WHO has urged countries to do mass testing to stop the spread of COVID-19.

—Kaela Malig/JCB, GMA News