Coronavirus infection risk: pathogens more infectious than previously thought

Coronavirus: pathogen is much more infectious than originally thought

The novel corona virus 2019-nCoV has been the subject of intensive research since its appearance in December. In a number of studies, scientists collect insights into the risk of infection and genetics, for example. It is now clear that the virus is significantly more infectious than previously thought.

Despite unprecedented measures, the new type of corona virus continues to spread in China. According to media reports, the death toll from this virus has exceeded that of the Sars pandemic 17 years ago. In the meantime there is more and more knowledge about the transferability of the germs. According to experts, they are significantly more contagious than was initially thought.

Virus is spread by droplet infection

The question of how contagious the new corona virus is is currently difficult to answer. It is known that the virus spreads through droplet infection - for example when coughing and speaking. "The pathogen is significantly more infectious than originally thought," explains infection epidemiologist Lars Schaade, Vice President of the Robert Koch Institute (RKI).

According to the virologist Christian Drosten from the Berlin Charité, many details of the infection are still unclear. "This cannot be reconstructed exactly. You probably get the virus in a similar way to catching a cold. ”Drosten considers it rather unlikely that symptom-free people can also be infectious, as occasionally reported.

According to Chinese doctors, the virus may also spread through the digestive system. They found the pathogen in stool samples after finding that some patients had diarrhea instead of the usual fever.

According to RKI information, it has not yet been finally clarified whether you can actually be infected in this way. According to information in China, the virus is also likely to be transmitted from mother to newborn.

What is striking is the discrepancy between the rapid spread in China and the fact that so far only a few people have been infected in other countries. The virologist Thomas Schulz from the Hannover Medical School (MHH) also explains this by saying that the pathogen in China probably circulated weeks before the authorities took rigorous measures.

"If you had done this a month earlier, the situation would probably not have escalated so much," says Schulz.

Unspecific symptoms

The new corona virus primarily infects cells of the lower respiratory tract. As a result, some symptoms of a cold, such as runny nose, do not appear to occur. In general, the symptoms of the new lung disease are non-specific. Fever, dry cough and breathing problems can also occur with flu.

"It is not enough just to test feverish people," said Drosten. "Some people only have mild cold symptoms with chills and sore throats." Sometimes patients can also have headaches or diarrhea.

The incubation period - the period between infection and the onset of symptoms - is two to 14 days. Suspected cases are therefore isolated for two weeks.

Infection is usually demonstrated by the detection of the genome of the coronavirus in the sputum, the slimy sputum when coughing.

How dangerous is the pathogen?

The question of how dangerous the pathogen is can hardly be answered at the moment. According to current data, the proportion of people who die from lung disease in China is around two percent - higher than that of the flu. In the flu pandemics of 1957 and 1968, the mortality rate according to Drosten was around 0.1 percent.

The specialist explains the high value in China by the fact that mainly serious cases are known there. “Many people in China only report when they are really sick. These cases are not representative. "

"We don't know the actual number of cases," says Schaade. Fall mortality is currently lower outside of China. The low death rate is encouraging at first, "but we have to keep an eye on it," said Schaade.

Clemens Wendtner, who looks after seven infected people at the Munich Clinic Schwabing, assumes that "the mortality rate is well below one percent, more likely even in the per mil range" He says: "It doesn't have much to do with a very, very dangerous illness."

There is no specific therapy for the condition

There is no special therapy for the disease. Seriously ill patients are treated symptomatically: with antipyretic agents, the treatment of any additional bacterial infections and sometimes mechanical ventilation.

Illness could decrease as the warmer season begins

The head of the national team of experts in the fight against the coronavirus, Zhong Nanshan, said on Monday that the coronavirus epidemic will peak in mid to late next week. According to German experts, it is difficult to assess whether this is realistic.

"I don't know the Chinese data and models," says Schulz, but he tends to be skeptical. "At the moment the curve is still going up steeply." Infection epidemiologist Schaade agrees: "I would be very careful with prognoses."

Drosten adds: “It is crucial whether China manages to stop the transmissions. I can imagine that. ”But there is also a second question, he emphasizes: does the virus nest in countries with poor health systems, for example in Africa or Asia, where it can hardly be controlled? Then there is a permanent threat of a new lung disease in the world.

Schulz suspects that the disease in China will decrease with the start of the warmer season - similar to flu and colds. "The question is whether she will come back next year." (Ad, source: dpa)

Author and source information

Video: How Contagious is COVID-19? Transmission, Spread, and R0 (January 2022).