US CDC: 25% of asymptomatic Covid-19 infections feel healthy

The patient was taken to Elmhurst Hospital in Queens. Photo: New York Times.
The patient was taken to Elmhurst Hospital in Queens. Photo: New York Times.

25% of people infected with asymptomatic corona virus, the director of the US quarantine agency (CDC) warned – adding an astonishing estimate of the incubation potential for Covid-19.

This figure shows that the effort to predict the direction of the disease and reduce the spread will be more complicated.

“This helps explain how the virus continues to spread throughout the United States,” CDC Director Robert Redfield told NPR radio on March 31.

The new data is forcing the CDC to “seriously reconsider” its recommendations, which have always been thought that people do not need to wear masks unless they are sick, according to the New York Times.

Researchers do not know exactly how many people are infected with the virus without feeling any symptoms. But that phenomenon has been reported in many individual cases, such as “patient Z”, 26, from Guangdong, was found positive on the 7th day after contact with the patient, at which time the virus was born in his nose and throat. But he did not feel anything strange.

Now researchers say “patient Z” is not just an isolated case. For example, up to 18% of people infected on the Diamond Princess yacht have no symptoms. A team in Hong Kong says about 20-40% of all infections in China happen before symptoms appear.

Such high rates of transmission without symptoms may explain why the new SARS-CoV-2 corona virus is the first virus not caused by the pandemic.

The virus spread like flu, and “have we ever thought of how to stop the flu from spreading, assuming there is no vaccine,” Dr. Michael Osterholm, an infectious disease specialist at the University of Minnesota, told New. York Times.

While vaccines are still being studied, the best way to curb this pandemic is to maintain a distance when exposed, experts say. Because a person may be infectious even if they are feeling well, just asking sick people at home is not enough.

That’s why many experts go against the recommendations of the CDC and the World Health Organization (WHO) and require everyone to wear a mask – to prevent people who do not know they have a disease that spreads to them. other.

Like flu, many experts now believe that the virus spreads through droplets containing viruses, both large and smaller than 5 microns in diameter, which infected people release into the environment, not only during coughing but even at breath time.

Experts emphasize that the virus concentration in the droplets is low, so simply running through or passing through an infected person is not enough for us to be at risk.

“If you only have direct contact with an infected person, you are very, very likely to be infected,” Dr. Benjamin Cowling, an epidemiologist at Hong Kong University, told the New York Times.

The risk increases for long-term exposure, like talking in person, or being in the same space for a period of time. Dr. Cowling said that in addition to making a confusing stance on the mask, “The World Health Organization (WHO) has often said drops from the respiratory tract are not contagious, a very confusing recommendation.” .