Four days after China announced that there were no new cases of coronavirus in Wuhan, at the center of its outbreak, people were still reporting positive for SARS-CoV-2 infection.

This raises concerns that the virus could still spread to the city. “There are still a few or a dozen asymptomatic people every day. It may not be determined whether transmission is completely cut off in Wuhan, “said an official with the Chinese Center for Disease Control and Prevention (CDC), referring to people who have the virus but have no symptoms.

Some asymptomatic people contract the virus but do not produce or show any symptoms, such as fever, cough, or muscle pain. These people have been reported in several countries, as the virus spreads to approximately 170 countries or regions, killing more than 18,900 and making more than 423,600 ill. Fortunately, more than 108,600 have recovered.

Symptom-free virus cases still found in Wuhan City
At the Wuhan Lung Hospital on March 19, medical workers guide patients during an aerobic exercise. Photo credit: Xiao Yijiu / Xinhua via Getty Images

Experts caution that although asymptomatic carriers have symptoms, it generally means that they cannot get sick from others; They can still transmit the virus to others. These asymptomatic people complicate efforts to stop the spread.

Many countries, including South Korea, count all who tested positive as confirmed. However, China also includes asymptomatic cases in its official count. It also provides the number of people in this category, which means that “zero new cases” will be taken at face value.

In late February, more than 43,000 people tested positive for COVID-19 without showing immediate symptoms.

How did they find out that people were infected if they had no symptoms? Asymptomatic coronavirus carriers were found in Wuhan City when patients were admitted to the hospital after medical observation at quarantine sites, exposure to an elevated risk of exposure to areas, or close contact with a sick person. Once the patients test positive, they are separated for two weeks and, if they show any symptoms, they will be classified as a confirmed case.

After the official count of new cases dropped to zero, the doctors and nurses who were sent to Wuhan began to leave the city. However, CDC officials in China are asking for a longer period of time as there are still some concerns about the situation in Wuhan and the Hubei region.

Iceland has tasted a higher percentage of its inhabitants than any other country. According to the country’s epidemiologist Thorolfur Gudnason, approximately 50% of those who tested positive had no symptoms of the virus.