The severe acute respiratory syndrome coronavirus (SARS-CoV-2) that causes COVID-19 led to 217.6 million infections and 4.51 million-plus deaths worldwide. The infection can range from asymptomatic to life-threatening and fatal disease pandemic. Presently, millions of people have recovered; however, clinicians are analyzing reports of patients with persistent severe symptoms and even substantial end-organ dysfunction due to SARS-CoV-2. Because COVID-19 is a new disease, much about the clinical course remains indecisive — in particular, the possible long-term health consequences, if any.
A study carried out on 104 COVID-19 passengers aboard the Diamond Princess - a cruise ship that was quarantined off the coast of Japan in February 2020, found that 76 of them had COVID-19 but were asymptomatic. CT scans showed that 54% of that group had lung abnormalities—patchy grey spots known as ground-glass opacities that signal fluid build-up in the lungs. Likewise, nearly 40 million COVID-19 infections in the US were detected, of which 35% were asymptomatic. After a detailed analysis, it was found that asymptomatic disease can cause serious harm among some people, which includes blood clots, heart damage, a mysterious inflammatory disorder, and long COVID. The latter is a syndrome that is marked by a range of symptoms, from breathing difficulties to brain fog that lingers after an infection.
Just as imaging scans have revealed damage to the lungs of asymptomatic persons, chest scans have shown abnormalities in the hearts, blood clots, and inflammation in asymptomatic infected persons. Thrombosis Journal and other publications have illustrated several cases of blood clots in the kidneys, lungs, and brains of asymptomatic patients. When these gel-like clumps get stuck in a vein, they prevent an organ from getting the blood it needs to function—which can lead to seizures, strokes, heart attacks, and death.
There have been relatively few of these case reports—and it’s unclear whether some patients had other underlying issues before contracting COVID-19 that could have caused a clot. In the research paper published in BMJ Case Reports, a case of renal blood clot suggests that the unexplained thrombus in otherwise asymptomatic patients can be a direct result of COVID-19 infection and serves as a call to the casualty department clinicians to treat unexplained thrombotic events as evidence of COVID-19.
Other studies reported harm to the heart. According to the research paper in JAMA cardiology by Daniels et al. (2021), cardiac MRI scans of 1,600 athletes who had tested positive for COVID-19 showed evidence of myocarditis or inflammation of the heart muscle in 37 people—28 of asymptomatic patients. Myocarditis can cause chest pain, palpitations, and fainting—but sometimes show no signs at all. Some cardiovascular specialists argue that myocarditis might resolve over time, perhaps even before patients know they had it, or it could develop into a more serious long-term health issue. There is also a need to compare the scans with a set taken just before an individual contracted COVID-19 to ascertain whether the COVID-19 infection caused the inflammation or not.
Additionally, asymptomatic infected persons are at risk of becoming COVID-19 long-haulers. This syndrome may include diverse combinations and often overlapping symptoms such as pain, breathing difficulties, fatigue, brain fog, dizziness, sleep disturbance, and hypertension. The rates of asymptomatic infections among long-haulers are underestimated or not precisely known.
Physicians have also examined case papers of children with asymptomatic COVID-19. They discovered a new condition called multisystem inflammatory syndrome in children below 14 that typically causes fever, rash, abdominal pain, vomiting, and diarrhoea. It can have harmful effects on multiple organs, including the heart that has trouble pumping blood to lungs that are scarred due to the COVID-19, according to a paper published in JAMA Network Open 2021. But the good news is that the problems are mostly resolved within six months. This is revealed in a study of 45 pediatric patients with heart problems, ranging from leaky valves to enlarged coronary arteries, published by Farooqi et al. in Pediatrics in 2021. The author recommends administering follow-up MRI scans even to patients whose heart troubles seem to have resolved to make sure there’s no longer-term damage, such as scarring. She also encourages parents to have their child evaluated if they have any persistent symptoms, even if the initial infection was mild or asymptomatic.
Scientists caution that there’s still so much unknown about the potential harm of asymptomatic infections. Many have called for a more in-depth investigation to get to the bottom of the long-term effects of asymptomatic disease, mainly focusing on why those effects occur and how to treat them. It’s also unclear what could be causing these lingering side effects. Scientists hypothesize that it could be an inflammatory response of the body’s immune system that persists long after an infection has been treated. Others suggest that there could be remnants of the virus lingering in the body that continue to trigger an immune reaction months after the COVID-19 infection peaked.
Although the possibilities are meagre that an individual with an asymptomatic infection will have an awful outcome, the continuing high rate of infections implies that more people will suffer post-COVID. The bottom line is to get vaccinated and prevent disease by following the essential COVID-19 protocols.
(The author is a freelance writer)