Spread COVID-19 With No Symptoms<br /> <br /><br /><br /> The medical establishment used to think (and mostly still does) that people with asymptomatic coronavirus infections might be contagious like infected people with coughs and fevers. Further confusion comes from the potential for people to spread the virus after they are infected, but prior to showing clear symptoms. These pre-symptomatic people may be able to spread the virus to others for up to three days before a telltale cough or fever develops, and this accounts for an estimated 40% of virus transmission, according to preliminary CDC estimates.<br /><br />news from the World Health Organization this week muddied the waters, underscoring how baffling the deadly new disease has been for clinicians and researchers worldwide.<br /><br />• Asymptomatic: An infected person who never shows signs or symptoms of infection. In some studies, people with subtle, mild symptoms have been included in this definition.<br />• Pre-symptomatic: An infected person who will eventually develop symptoms, but so far has not.<br />Headlines have focused on the WHO‘s Dr. Maria Van Kerkhove, who leads the emerging disease and zoonosis unit. She claimed—then backed away from the claim—that spread of coronavirus from people who never develop symptoms is “very rare.” Meanwhile, much of the popular press ignored two studies on the topic that seem to contradict her earlier statement.<br />“From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual,” Dr. Van Kerkhove said Monday. “We have a number of reports from countries who are doing very detailed contact tracing. They're following asymptomatic cases, they're following contacts, and they're not finding secondary transmission onward.”<br />Her comments were met with immediate skepticism by WHO colleagues, and Dr. Van Kerkhove backpedaled the next day, calling asymptomatic spread a “really complex question.” She also said it was “misunderstanding to state that asymptomatic transmission globally is very rare.”<br />On Wednesday, Dr. Anthony Fauci called the statement “not correct” on ABC’s Good Morning America, and pointed out that between 25% and 45% of those infected never show symptoms.<br />What made this statement so controversial? And what data are available to help understand the spread of COVID-19 from an asymptomatic carrier of the disease?<br />Studies Suggest Asymptomatic Carriers Still Contagious<br />As many as 86% of the people initially infected in Wuhan, China became sick from people who were not sick enough to visit the doctor, scientists found in a paper published in Science May 1. These could have been people with no symptoms (asymptomatic) or people who had mild enough symptoms that they caused little concern.<br />Mild symptoms of COVID-19 infection include loss of sense of smell and low fever.<br />This study was co-authored by Jeffrey Shaman, a professor at Columbia University who forecasts infectious disease outbreaks. His study focused on those infected before Wuhan entered an unprecedented lockdown to stop further infection.<br />The paper concluded that people without any documented symptoms (which could include people with mild symptoms) were about half as infectious as people with serious symptoms, but together they caused a majority of new infections, Shaman told Bloomberg.<br />At the end of May, researchers in Wuhan, China published a study of 78 people who were exposed to the Huanan seafood market or who had close contact to another patient with COVID-19. All were infected with SARS-CoV-2, the virus that causes COVID-19.<br /><br /><br /><br />Source: https://www.medicinenet.com. <br /><br />