COVID-19: New research finds that people can be asymptomatic to disease
Even though a broad review of studies have found that most people with COVID-19 develop symptoms, some recent studies have shown evidence that some people can be asymptomatic, NBCNews reported. There could be asymptomatic spread amongst the public as well.
Two of such studies which were published on Tuesday did shed more light on the 'silent spread' of COVID-19.
One of the studies which was published in the journal, Thorax, reported that asymptomatic people could carry as much of the virus in their respiratory tract and throat as much as people who show symptoms of the disease.
The second study, which is a review study published in Plos Medicine discovered that while many of the infected people develop symptoms, they might have tested positive before the symptoms began.
When both studies are taken together, it highlights the need to take seriously, the preventive measures that agencies and governments have put in place to curb the spread of the virus.
Dr William Schaffner, an infectious disease expert at Vanderbilt University Medical Center in Nashville, Tennessee, speaking in line with this said, "Even though we're seemingly healthy, we have to wear masks".
A glimpse into the two research that studied the spread of COVID-19
For the Thorax study, researchers at the Asan Medical Centre in Seoul, South Korea compared the viral load (the amount of virus present in the body) among 183 COVID-19 patients.
Out of the 183, 144 had mild symptoms of sore throat, appetite loss and runny nose while 39 never showed any symptoms but were tested because they had been identified as having been in contact with people that were infected.
There is need for mass testing, development of vaccine as well as strict adherence to COVID-19 measures as many people are asymptomatic to the disease and can spread it to others
Swab samples which were taken from the noses and throats of patients from both groups showed no difference in the viral loads. This suggests that both groups are capable of spreading the virus to others.
However, according to Dr Schaffner, it is unclear if both groups are equally as infectious.
"Considering that most asymptomatic individuals with COVID-19 are likely to go unnoticed by health care workers and continue to reside within communities, such individuals may act as an essential driving force for the community spread of COVID-19 and the ongoing pandemic", the study authors wrote.
For the study reviewed in Plos Medicine, 20 per cent of the participants were found to be asymptomatic.
In the report, researchers at the University of Bern in Switzerland pooled data from 79 studies. The data was that of people infected with the coronavirus from March to June. The analyses included more than 6,600 patients with follow-up data.
The Swedish review compared between asymptomatic and pre-asymptomatic cases (people who test positive for the virus when they still feel well but later develop symptoms).
At the point of testing, it is impossible to tell whether a person without symptoms will develop them later. From the researchers' estimation, 20 per cent of the patients who tested positive for COVID-19 never developed symptoms.
Others turned out to be pre-symptomatic, which means that they did not develop symptoms until after they were tested.
Both studies reinforce the need for a vaccine and strict adherence to precautionary measures
"Both of these studies reinforce the need for a vaccine - and even before that, masks, social distancing, hand hygiene - all to diminish the transmission of this virus", Dr Schaffner said.
Infectious disease experts in the United States had earlier acknowledged the fact that the virus can indeed spread from both asymptomatic and presymptomatic people.
The study authors in Switzerland also wrote, "Social distancing measures will need to be sustained at some level because droplet transmission from close contact with people with asymptomatic and presymptomatic infection occurs".
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