According tomedia reports, over the past few months, people often debate how strong lying the virus is in the asymptomatic of pneumonia. The most recent was the vague remarks made by an expert from the World Health Organization (WHO) at a press conference. After the expert suggested that asymptomatic transmission was “very rare,” the WHO eventually said they just didn’t have enough information.
It is difficult to get a clear answer. It requires careful and detailed investigation to understand how often people carry the virus without symptoms and how likely they are to pass the virus on to others in a healthy state.
Mark Slifka, a professor of virology at Oregon Health and Science University, says this has happened several times in the past few months. But that’s clearly not enough, and more data is needed to resolve the dispute.
The confusion began in January when a report in the New England Journal of Medicine (NEJM) said a German businessman had been infected with the new crown virus by a colleague from Shanghai. The Shanghai colleague showed no symptoms during his time in Germany, the report said. Some experts now treat it as asymptomatic.
But it turned out that she had mild symptoms, and during that time she felt a little fever, tiredness and slight pain.
So the first challenge for the researchers was reflected in the NEJM error, which was that it was difficult to tell if a person really did not have any symptoms of neo-coronary pneumonia. From the above example it is not difficult to conclude that some signs of infection may be easily ignored, and some people with slight itching in their throats may not think they are sick. If scientists try to find out if a person who tested positive has symptoms, they usually rely on that person to express their feelings. In fact, such self-reports may not be accurate.
If a person really has no symptoms then the next step is to check if they will develop these symptoms after that. Many studies of cases of new crown pneumonia have only been tested once on people who initially tested positive. If these people do not feel unwell, they are sometimes classified as asymptomatic. However, many of them later develop symptoms, which scientists classify as “pre-symptoms.”
“We shouldn’t use the word ‘asymptomatic’ unless you come back at least 14 days later and ask the person, ‘Are you all right?’ “Slifka said.
In order to obtain accurate data, researchers must track them for at least 14 days.
Once scientists have long-term data, they can begin to check how often people who are asymptomatic or have symptoms infect others. Studies have shown that people have high levels of the virus in their throats before they develop symptoms. One study found that people who had never had symptoms also had a copy virus in their noses and throats, but fewer people ended up feeling unwell.
These studies suggest that people who are theoretically asymptomatic can spread the infection to others. They have viruses in their noses and throats that can be transmitted to others through salivadrops or occasional sneezes. But that doesn’t mean they’re really going to do it. Slifka points out that the number of viruses in a person’s nose is still only an indirect measure of its infectiousness.
Dr. Abraar Karan, a researcher on the new crown pneumonia response from Harvard Medical School, points out that people who don’t feel uncomfortable may not be coughing or sneezing.
Information on the number of viruses floating in asymptomatic populations and estimates of the amount of respiratory droplets they produce can be used to infer how they transmit the virus. But these are just models that don’t answer the question directly. Rather, if someone does have the new coronavirus from asymptomatic patients then they need to follow up in detail and undergo more tests.
Karan says it’s easier to reproduce when an infection travels from one person to another and when it occurs if a group of people are regularly tested.
Natalie Dean, an epidemiologist at the University of Florida, wrote on Twitter that in order to say that a person is sick because someone else has tested positive but has no symptoms, researchers must also rule out all other causes of their illness. This is difficult to do in places with high infection rates. If the virus spreads in the community, the person may have been infected when touching the doorknob in a public place or supermarket.
Several research groups have tried to sort out all the clutter. One study tracked people who contracted the virus while working in a call center in South Korea. During the survey, some workers developed symptoms, some later developed symptoms, and some never experienced symptoms. None of the people who came into contact with staff without symptoms were infected with the virus. Another detailed study carefully tracked the path of infection in 157 patients with new coronary pneumonia in Singapore, and found that only 10 were infected from asymptomatic patients.
Early data suggest that even people in the nose who have not yet developed symptoms or have never had symptoms spread the new coronavirus less frequently than those with symptoms. However, these studies are relatively small, so it is not enough to determine who may have spread the new coronavirus.
Because the new coronavirus is still a new virus, scientists still have a lot to know about it.
“We’re still working on this, and we can’t quite determine the exact number of pre-symptom cases, or asymptomatic cases, or symptomatic cases that spread,” Karan said. “
Slifka says researchers should continue to look for better data while people take these steps. In areas with low rates of infection, public health officials can conduct the necessary detailed contact tracing to determine if anyone has contracted the virus from asymptomatic people. The more state and city tests are done, the more likely they are to find people who carry the virus around without any symptoms. “We should monitor every case, including pre-symptom, asymptomatic and symptoms, and check for secondary incidence. Then we’ll find out. “