Covid-19: What it means to be ‘asymptomatic’

Presenting with Covid-19 symptoms is different for each person. Most infected people, especially children, will only develop mild to moderate symptoms.

On average, it takes five to six days from when a person was infected, for the virus to show any symptoms.  It can, however, take up to 14 days, according to the Annals of Internal Medicine. Some pre-symptomatic people who have been infected and are incubating the virus don’t show symptoms yet, while people can be carriers and infect other people in this period.

It is accepted among scientists that there is no single study yet to clarify the percentage of people being asymptomatic, but, studies in 21 countries have shown that Covid-19 positive cases that asymptomatic varied between 22% and 80%, or showing very mild symptoms.

Many people infected with the virus show no signs of the disease, also referred to as being asymptomatic, and people who carry the Covid-19 virus without any knowledge of it, can cause a large number of infections by spreading the virus.  Studies found that the virus sheds at high concentrations from the nasal cavity even before symptoms develop.

According to the World Health Organization (WHO) some cases of asymptomatic carriers have been confirmed by finding and testing people who were in close contact with Covid-19 patients. For those who tested positive without presenting with symptoms, follow-up exams confirmed that roughly 25% continued to show no signs. These persons could be carriers or transmitters of the virus. A study conducted in Iceland showed that 50% of people who tested positive, had shown no symptoms.

Covid-19, or the  SARS-CoV-2virus, has infected more than four million people worldwide and continues to spread rapidly in just the last five months, compared to the eight months it took to control the SARS virus after SARS-CoV-1 virus had infected 8 100 persons in limited geographic areas. The difference in transmission and spread, and a key factor is thought to be the high level of SARS-CoV-2 shedding in the upper respiratory tract in Covid-19, even among pre-symptomatic patients, which distinguishes it from SARS-CoV-1, where replication occurs mainly in the lower respiratory tract.

This means in simple terms, that Covid-19 is spreading fast because of the transmission from asymptomatic persons, and this supports the case for the general public to use face masks when in crowded outdoor or indoor spaces and to keep to social distancing measures.

Just screening for symptoms, then, means that a lot of positive cases might be overlooked, and testing for antibodies is important to really know the actual number of positive cases. Some asymptomatic cases might become symptomatic within a week, especially among children and young adults. It is possible, according to scientists, that the bulk of Covid-19 infections may remain unrecognised if testing is not increased, and as a result the potentially huge number of positive cases might not be detected due to the fact that people remain asymptomatic.

*Notice: Coronavirus reporting at Caxton Local Media aims to combat fake news

Dear reader,
As your local news provider, we have the duty of keeping you factually informed on Covid-19 developments. As you may have noticed, mis- and disinformation (also known as “fake news”) is circulating online. Caxton Local Media is determined to filter through the masses of information doing the rounds and to separate truth from untruth in order to keep you adequately informed. Local newsrooms follow a strict pre-publication fact-checking protocol. A national task team has been established to assist in bringing you credible news reports on Covid-19.
Readers with any comments or queries may contact National Group Editor Irma Green (irma@caxton.co.za) or Legal Adviser Helene Eloff (helene@caxton.co.za).