As we take precautions against Covid-19 infections, many people still think that the disease is not that serious as many of the cases are “mild” or even “asymptomatic”.
But Covid-19 affects different people in different ways. While many patients were able to recover from their symptoms at home, little is known about possible lasting effects.
Some cases show no symptoms at all. But not only was there a concern that these people could spread Covid-19 to other more vulnerable people, there is some evidence that there may be some lasting damage, even if you showed no symptoms.
In a recent study, Chinese researchers from Wuhan University performed CT scans on 58 patients who tested positive for SARS-CoV-2 but displayed no symptoms. Of these asymptomatic patients, 27% did develop symptoms after their diagnosis, which included fever, shortness of breath, dry cough, fatigue and diarrhoea.
But another aspect of the study was even more concerning. All of these 58 patients, whether they presented symptoms or not, showed lesions on their lungs.
The research was published in The Journal of Infection.
“Lesions were fused to form patchy, crazy-paving signs, or diffusion pattern, distributed in multiple lung lobes or bilateral, and a few patients showed consolidation in CT imaging,” the researchers wrote in the study.
Signs of pneumonia without symptoms
Another study, recently published in Nature Medicine, documents the clinical patterns of those with asymptomatic infections. The people who were studied developed signs of minor lung inflammation, which is very similar to so-called “walking pneumonia” or atypical pneumonia – where they don’t show any symptoms, but where there are significant signs of inflammation in the lungs.
This damage presented as striped shadows or ground-glass opacities, even though the participants showed no other symptoms.
"To find so many asymptomatic patients with such significant changes on CTs is quite surprising," stated Dr Alvin Ing, a professor of respiratory medicine at Macquarie University, in an article.
It is possible that the lung damage that shows up on CT scans may clear up in the future, as these abnormalities can be caused by many factors and the exact mechanisms behind them are not clear yet.
“It can be a little bit of fluid in the lungs, sometimes a little blood in a lung or sometimes just a small area of inflammation in the lung," says Dr Neil Schluger, chief of pulmonary, allergy and critical care medicine at the Columbia University Medical Center.
Spreading the virus silently
Besides possible undetected lung damage in asymptomatic cases, it’s still unclear to exactly what extent asymptomatic carriers can spread the virus. The study in Nature Medicine also determined that pieces of the coronavirus from asymptomatic people can linger in swab samples – while this doesn’t mean that they stay infectious forever, it does mean that they have the capability to spread the virus and infect others unknowingly.
In South Africa, many testing facilities will not consider you if you are not showing symptoms or have a referral from a doctor. Many asymptomatic cases will therefore never be tested and diagnosed with a confirmed positive result, but will go into public spaces and spread the virus to those who may not be so lucky.
Dr Jorge Mercado, a pulmonologist at NYU Langone Hospital in the US, stated that he has seen many instances in New York where people come to hospital for non-Covid-19 related issues but end up testing positive for the virus.
The US Centers for Disease Control and Prevention (CDC) recently estimated that 35% of cases are asymptomatic, and that 40% of transmissions occur before people develop symptoms.
However, the exact percentage of asymptomatic cases worldwide is hard to pinpoint and the exact permanent outcomes are not yet known. For that reason, we are urged to wear masks, practise physical distancing and be careful around vulnerable people such as the sick and elderly.
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