Asymptomatic COVID-19 patients become a gap in epidemic prevention, 60% of global cases still waiting to be discovered

Since community transmission of the novel coronavirus (Covid-19) broke out in Italy in late February, in just over two weeks, confirmed cases have shot up in a straight line to 7,000. Although more than 600 people have recovered, it is still the country with the most severe outbreak outside Asia. In the early hours of March 8, an emergency decree was issued: without a permit, no one may enter or leave the Lombardia region and 14 other provinces, involving about 16 million people, a quarter of the national population.

Why is Italy's outbreak so severe? What lessons does Italy's experience offer? A reporter from Newsmarket stationed in Italy brings on-the-ground reporting, divided into two articles. This is series 01; to read 02, please click here.

"Invisible patients" are a gap in epidemic prevention, the average age of the deceased is 81

Called "the first recovered patient," 47-year-old Sara strongly disagrees, "Everyone says I've recovered. The problem is, I was never sick." Yet more than ten days ago, her novel coronavirus (Covid-19) test came back positive. Although she had not the slightest typical symptoms of fever or cough, she is currently self-isolating at home.

Family doctor Marco also contracted the novel coronavirus commonly known as "Wuhan pneumonia." His only symptom was a bit of rhinitis. Sara and Marco are not a minority. According to statistics from the Italian Ministry of Health, half of those who test positive have no symptoms or only mild symptoms, and this was used to ease people's panic.

However, these "invisible patients" happen to be the gaps in the epidemic prevention net. Without realizing they have become carriers, they continue living normally, moving about and traveling, and those around them are unprepared, allowing the cunning novel coronavirus to infiltrate every corner of the world.

Compared with the ferocious SARS with a fatality rate of 10%, the novel coronavirus, currently estimated by the World Health Organization (WHO) to have a fatality rate of 3.4%, appears relatively mild. But not everyone is as fortunate as Sara and Marco, spared too much suffering from the virus. The novel coronavirus is more transmissible. Once the number of infected people is large, the final death toll is still worrisome, especially since elderly people with chronic diseases are exposed to extremely high risk. In Italy, where those over 65 make up 23% of the population, the death toll has already exceeded 200, the average age of the deceased is 81, and 75% of the dead were over seventy.

The virus's disguise: many patients have no pneumonia symptoms

Wuhan was locked down on January 23, with people confined to their homes, but the virus could not be stopped from racing toward the world. World Health Organization Director-General Tedros Adhanom Ghebreyesus said on February 9 that there would be more and more Wuhan pneumonia cases with no history of travel to China, "What we are seeing may only be the tip of the iceberg."

The words were still echoing when Italy hit a huge iceberg on February 20. In just two weeks, three imported cases surged to about 6,000 confirmed cases. Taiwan's customary term "Wuhan pneumonia" increasingly fails to accurately describe the power of what is officially named "coronavirus disease 2019" (Covid-19). The disease does not only occur in Wuhan, and many patients have no pneumonia symptoms.

The novel coronavirus, adept at disguise, evades the monitoring of the medical system, secretly crosses borders, and silently attacks human health. Some patients with mild symptoms rest at home or take medicine on their own and never see a doctor. Even if they go to the hospital, the common symptoms listed by the World Health Organization - fever, dry cough, fatigue, phlegm - are extremely similar to colds and flu, making it very hard for frontline doctors to see through the trouble caused by the intractable novel coronavirus. Not to mention that some people, like Sara, do not feel sick at all.