“Now it seems to us that SARS-CoV-2 has a dual nature,” write the cardiologist Eric Topol and his colleague, ethologist Daniel Oran a few months after the start of the pandemic. The first face COVID-19 scientists call “tragically lethal”: bedridden patients, intensive care, artificial ventilation of the lungs. However, by collecting data of fifteen studies, a poplar with a colleague, undertook to describe the second face of the disease — “surprisingly inoffensive” — as the researcher dubbed asymptomatic carriers of the virus, which, according to his calculations, at least 40 percent among all infected with SARS-CoV-2. But upon closer inspection, this face may not look so harmless — if the carriers will be able to spread the infection further.
People who change the world
From the point of view of an epidemiologist, “infected” and “sick” some infection — not one and the same. Having infected the person HIV can for decades to hide from his master, without causing any visible difficulties (“disease”). Carriers of cholera, according to various estimates, ten times more than those who hurt her seriously. And the tubercle Bacillus, according to the who, harbouring in its body every fourth inhabitant of the Earth.
But if a latent carrier of TB is not contagious, and from cholera and HIV is easy to prevent, some pathogens have successfully used asymptomatic carriers to capture new territory. The most famous of these media, Mary Mallon (better known as Typhoid Mary), provoked in new York a couple of dozen local outbreaks of typhoid fever — the number of places where she worked as a cook and laundress. And when the United States started the vaccination campaign against polio, carriers have become the children of a weakened polio virus in their body (actually, vaccines) was enough to infect unvaccinated adults.