The Chance That You Have COVID Without Symptoms Is Growing, Study Says
Recent research has found that even more patients never show COVID symptoms than previously thought.
The novel coronavirus has proven to be an elusive foe for Americans coast to coast for nearly six months now. Part of this is because of the sheer speed and ease at which the virus can spread, mostly through droplets from a contagious person's nose or mouth. However, so many patients never actually develop symptoms, making it more likely that they'll continue to go out in public and accidentally infect others. And according to recent research, even more people may be asymptomatic COVID cases than originally thought. A new study, which used data from two surveys in Italy, found that more than 40 percent of coronavirus patients may be asymptomatic.
The study was published in the journal Nature in June, and the results—out of the Italian town of Vò—showed that 42.5 percent of patients who tested positive ultimately never showed any symptoms of the virus.
The findings fall closely in line with another recent study out of South Korea. According to those results, not only are about 30 percent of patients asymptomatic, but patients showing no symptoms still carry and shed the same amount of virus as those who are symptomatic. "They don't look any different from the symptomatic population," Marta Gaglia, a virologist at Tufts University, told The New York Times commenting on the study. "There's no actual reason to believe a priori that they would transmit any differently."
Both sets of findings support the Centers for Disease Control and Prevention's (CDC) "current best estimate" for asymptomatic cases. In May, the CDC created five "COVID-19 Pandemic Planning Scenarios," using data to estimate a range of possible COVID trajectories in the U.S. At that point, the CDC's "best estimate" was that 35 percent of COVID cases were asymptomatic. In July, the CDC updated their predictions using new data through June 29. Now, their "current best estimate" is that 40 percent of all people infected with coronavirus show no signs or symptoms—a notable 5 percent increase that could jump again if the Italian study's findings are any indication.
Meanwhile, the World Health Organization (WHO) was taken to task by the medical community for their "pooled estimate" on asymptomatic spread, claiming that as few as 16 percent of COVID-19 patients worldwide are asymptomatic. However, they blame their lower figures on studies that failed to follow up with patients who may have never developed symptoms after testing positive.
Still, experts point out that it's the common lack of symptoms that make following social distancing and face-covering guidelines all the more important. "You don't realize, probably innocently, that you are inadvertently propagating the outbreak," Anthony Fauci, MD, told MarketWatch in early August. "You are becoming part of the problem because, even if you get infected without any symptoms, it is likely that you are going to infect someone else." And for more on what happens when you do feel ill from coronavirus, check out If Your Symptoms Appear In This Order, You Likely Have COVID, Study Says.