Some scientists are confident that the immune system’s aggressive response to the virus is only part of the story.
Asymptomatic cases don’t get much attention from medical researchers, in part because these people don’t go to the doctor and thus are tough to track down. unitednations/Unsplash
By Emily Laber-Warren/Undark
One of the reasons COVID-19 has spread so swiftly around the globe is that for the first days after infection, people feel healthy. Instead of staying home in bed, they may be out and about, unknowingly passing the virus along. But in addition to these pre-symptomatic patients, the relentless silent spread of this pandemic is also facilitated by a more mysterious group of people: the so-called asymptomatics.
According to various estimates, between 20 and 45 percent of the people who get COVID-19—and possibly more, according to a recent study from the Centers for Disease Control and Prevention—sail through a coronavirus infection without realizing they ever had it. No fever or chills. No loss of smell or taste. No breathing difficulties. They don’t feel a thing.
Asymptomatic cases are not unique to COVID-19. They occur with the regular flu, and probably also featured in the 1918 pandemic, according to epidemiologist Neil Ferguson of Imperial College London. But scientists aren’t sure why certain people weather COVID-19 unscathed. “That is a tremendous mystery at this point,” says Donald Thea, an infectious disease expert at Boston University’s School of Public Health. Read more >>