The Lancet: Beware of New Coronavirus Carriers May Have No Clinical Symptoms

Studies have shown that the symptoms caused by the new 2019 coronavirus (2019-nCoV) appear to be similar to severe acute respiratory syndrome (SARS), and may be human-to-human and cross-city transmission. More scientific principles about the clinical symptoms and spread of the new coronavirus infection in Wuhan are being revealed.

The Lancet, a leading medical journal, published a paper on the study of the 2019 new coronavirus online on January 24. Studies have shown that the symptoms caused by the new 2019 coronavirus (2019-nCoV) appear to be similar to severe acute respiratory syndrome (SARS), and may be human-to-human and cross-city transmission.

The Lancet: Beware of New Coronavirus Carriers May Have No Clinical Symptoms

Most infected people are healthy people

This is the first time the Lancet has published online two original studies on the “new coronavirus”. Preliminary data from Wuhan, China, showed that the first 41 cases of 2019 new coronavirus infection and SARS had some similar symptoms. Another study published also showed that the new coronavirus was transmitted from six family members in a family of seven in China, and researchers stressed the need for stringent control measures to deal with the outbreak.

The authors say these early findings are important, and although they involve only a small number of patients, they still need to be monitored carefully, close contacts are tracked, and animal host tracing and exploring the route of transmission from animal hosts to humans as soon as possible to minimize the likelihood of the continued spread of the 2019-nCoV outbreak.

In addition, although most of the cases are related to the South China Seafood Market in Wuhan, China, the initial source of the infection is still unknown. Studies have shown that 2019-nCoV is likely to be closely related to coronaviruses carried by Chinese horseshoe bats. Currently, six coronaviruses (including seven, including 2019-nCoV) are known to cause respiratory diseases in humans, but so far only infectious atypical pneumonia (SARS) and Middle East Respiratory Syndrome (MERS) have led to large-scale outbreaks and high mortality rates (10 per cent and 37 per cent, respectively). Currently, no specific anti-coronavirus drugs or vaccines have been shown to be effective in humans.

In the lancet’s first new study, researchers combined clinical features, laboratory tests, and imaging results with epidemiological data to analyze the first 41 confirmed cases of infection with 2019-nCoV in Wuhan between December 16, 2019 and January 2, 2020. As of 22 January 2020, 28 (68%) of the 41 patients included in the study had been discharged from the hospital.

The results showed that the proportion of patients aged 25-49 and 50-64 years old was 49%, 34%, the median age of patients was 49 years old, and most of them had been to the South China Seafood Market (66%, 27 cases), mainly male (73%, 30 cases).

As with SARS, the majority of infected people are healthy, with less than one-third of cases combined with chronic diseases such as diabetes (20 per cent, 8 cases), hypertension (15 per cent, 6 cases) and cardiovascular disease (15 per cent, 6 cases).

Similarly, patients with 2019-nCoV infection also showed more clinical symptoms. All patients admitted to the hospital had pneumonia, with most clinical manifestations of fever (98 per cent, 40 cases), cough (76 per cent, 31 cases) and fatigue (44 per cent, 18 cases). More than half of the patients also had breathing difficulties (55 percent, 22 cases), but headaches and diarrhea were rare.

About one third of patients developed acute respiratory distress syndrome (29 per cent, 12 cases) or were in intensive care (32 per cent, 13 cases), of which 6 died. The researchers say cytokine storms can be seen in critically ill patients, but more research is needed to clarify how 2019-nCoV affects the human immune system.

The study’s authors, Professor Cao Bin of the China-Japan Friendship Hospital and Capital Medical University, explained: “Although some symptoms are similar to SARS (e.g. fever, dry cough, dyspnea), there are some important differences, such as the absence of upper respiratory symptoms in patients with 2019-nCoV infection (e.g. runny nose, sneezing, sore throat) and intestinal symptoms (e.g. diarrhea, seen in 20-25% SARS patients).

“It is difficult to accurately understand the mortality rates associated with this new virus, as it is often easier to focus on critical cases in the initial stages of an epidemic and may overlook lighter or asymptomatic cases,” explains co-author Dr. Lili Ren, from the Institute of Pathogen Biology at the Chinese Academy of Medical Sciences.

The researchers also point to some limitations of the study, including the difficulty of accurately assessing risk factors associated with disease severity and mortality due to the limited number of cases, and they call for larger studies in outpatient clinics and communities to confirm the complete disease spectrum of patients infected with 2019-nCoV infections.

Carriers of the virus may have no clinical symptoms

The second paper, the first genetic analysis study, examined a family of seven who had been treated for unexplained pneumonia, proving that there had been four generations of transmission in 2019-nCoV. Of these, 2019-nCoV was found in five people who had recently visited Wuhan, and the same virus was found in another family member who was not travelling with him, and only one child was not infected. Importantly, another child infected with 2019-nCoV did not show clinical symptoms, suggesting that the carrier may be spreading the disease within the community without knowing that he or she is infected.

“Strict prevention and control measures are needed in the early stages of the outbreak,” the authors stress. It is worth noting, however, that the study simply reflects a family cluster, and the ability of the virus to spread remains unknown.

WHO Director-General Tedros Adhanom Ghebreyesus said that while no significant mutations have been detected, people should be very careful to keep a close eye on changes in the virus. WHO also said it was not yet possible to determine whether the new coronavirus could continue to spread from person to person in the third and fourth generations.

On January 24th France reported two cases of the new coronavirus for the first time, the first time the 2019-nCoV virus has been transmitted to Europe. The first financial reporter interviewed Professor Antoine Flahault, Director of the Institute of Global Health at the University of Geneva. Flahault stressed the importance of isolating infected and potential infections, but said that because some infected people are not fully characterized or even asymptomatic, it also raises concerns about the global spread of the virus.

“China has learned from the prevention and control of the SARS virus in 2003, and it has made great progress in detecting the virus genome within two weeks and sharing it with the World Health Organization,” Professor Flahault told First Financial. “With this in mind, Professor Flahault believes the outbreak is likely to be better controlled than the SARS outbreak in 2003, with the number and mortality rate likely to be lower than SARS, and he says it is impossible to predict whether the outbreak of the new coronavirus will last as long as SARS for half a year.

“2019-nCoV and SARS are the same virus family, outbreaks in the same region, the same transmission route, the same pathogenesis, but from preliminary data, the mortality rate for 2019-nCoV is much lower than SARS (3% vs 11%), although this is still to be confirmed. Professor Flahault told First Financial.

Professor Flahault told First Financial: “Isolating infected cases is not a warning in itself, but it in turn means that it is almost impossible to keep the outbreak in full control in one place, in a world with a high level of population mobility.” “