It’s easy to be complacent about COVID-19. Most people experience only mild issues – fever and coughing, maybe congestion and shortness of breath.
But the coronavirus is capable of causing much more than a simple respiratory illness, affecting organs throughout the body, experts say.
“We see people have symptoms from almost head to toe in terms of how they feel, how they function and what they can do,” said Dr. Adrian Hernandez, a cardiologist who is director of the Duke Clinical Research Institute in Durham, North Carolina.
The new year started with an increase in COVID-19 hospitalizations in the U.S., prompting Hernandez and other experts to advise caution, especially for those at high risk.
While the short-term effects of COVID-19 can be flu-like, even mild cases can lead to long COVID – a constellation of problems that can persist for weeks or months. More than 200 symptoms have been linked to long COVID, said Hernandez, who has overseen many COVID-19 studies.
Because COVID-19 typically affects breathing and can lead to problems such as pneumonia, many people may think it’s primarily a lung disease. It’s not that simple, said Dr. Nisha Viswanathan, director of the long COVID program at the David Geffen School of Medicine at the University of California, Los Angeles.
“I would argue that COVID-19 is not a disease of the lungs at all,” she said. “It seems most likely that it is what we call a vascular and neurologic infection, affecting both nerve endings and our cardiovascular system.”
It’s no surprise that experts say SARS-CoV-2 – the name of the virus that causes COVID-19 – is complex, with many of its pathways just beginning to be understood. But some things are becoming clear. One of the best reviews of long COVID symptoms, Viswanathan said, appeared last January in Nature Reviews Microbiology. It detailed the disease’s effects throughout the body, including the pancreas, blood vessels and reproductive system.
“SARS-CoV-2 is excellent at triggering your immune system to go from zero to 100,” said Dr. Lindsay McAlpine, a neurologist who is director of the Yale NeuroCovid Clinic in New Haven, Connecticut. That revving of the immune response leads to both a “wide swath of inflammation” and excessive blood clotting, she said.
“Perhaps the viral replication is going on in the lungs and nasopharynx (the area at the top of the throat that connects the nose to the respiratory system). But the inflammation that the virus triggers is systemic,” McAlpine said.