Is Omicron's virulence "heavy"?
Cao Bin, vice president of the China-Japan Friendship Hospital, director of the Department of Respiratory and Critical Care Medicine, and deputy director of the National Center for Respiratory Medicine, gave the answer: "Milder but not mild." (seemingly lighter, but not really light) December On the evening of the 21st, Cao Bin was a guest in the live broadcast room of the vertical self-media "Respiratory World" of China Respiratory Sciences. When he talked about the topic of severe illness and death of the new crown, it was difficult to conceal the exhaustion on his face.
In his view, the risk of hospital admissions, ICU admissions, mechanical ventilation, and death for Omicron infection is statistically reduced compared to the Delta strain, but due to its transmissibility Far more than Delta, as the base of infected people increases, it will cause more excess deaths.
He cited reports from the United States showing that 8 weeks before the Omicron epidemic, there were 2,294 excess deaths in the United States, which was much higher than the 1,975 deaths in the 23 weeks before the Delta epidemic.
"The total death toll caused by Omicron cannot be ignored." Cao Bin said, "Respiratory infection doctors in various hospitals are well aware that there are also a lot of viral pneumonia caused by Omicron, and some of them are very serious. .”
Cao Bin suggested that vulnerable groups should receive antiviral drug treatment as early as possible in the early stage of the disease, and prepare a finger clip oximeter for severe monitoring.
He mentioned that some elderly people still have no obvious chest tightness or dyspnea when they are severely hypoxic (even when the blood oxygen saturation is lower than 70%). "This is very dangerous and needs to be inhaled immediately."
Omicron can cause viral pneumonia a week after infection
According to Cao Bin, recent statistics from the China-Japan Friendship Hospital show that most patients can turn negative in nucleic acid in 5 to 7 days, and only 10% of them turn negative in more than seven days.
Severe illness means the potential for death, including the aggravation of underlying diseases (such as tumors, cerebral hemorrhage, cerebral infarction, liver cirrhosis, uremia, etc.).
"We have also seen that the severe illness of a large number of patients is indeed caused by viral pneumonia, which mostly occurs in vulnerable groups, such as the elderly over 65 years old, obesity, comorbid underlying diseases, tumors, immunodeficiency, etc., but the most frightening thing is that there is no obvious basis It can also cause Omicron viral pneumonia.” Among the four cases of Omicron viral pneumonia shared by Cao Bin, there was a 50-year-old man with no obvious underlying diseases, and a 48-year-old man The man had been vaccinated three times, but had obesity and a ten-year history of hypertension.
Omicron virus pneumonia is characterized, often one week after infection, by a characteristic radiographic appearance of diffuse ground-glass opacities in both lungs.
"Now we have seen many critically ill patients with severe respiratory failure, requiring mechanical ventilation in the prone position, and even shock caused by the virus." Cao Bin said.
According to Cao Bin, the severity of COVID-19 is determined by both viral infection and host response. The direct mechanism is virus infection and replication causing cell death and tissue damage, and the indirect mechanism is secondary organ damage caused by host abnormal immune response and cytokine storm. .
This means that the medication is different at different stages of the disease: the use of antiviral drugs in the early stage to inhibit viral replication as soon as possible will significantly reduce cell and tissue damage, which is the key point of treatment; and when the viral replication declines, immunomodulatory drugs need to be used, and For high fever and cough, symptomatic treatment drugs should be used, and vital signs should be closely monitored for high-risk groups.
For patients with severe hypoxia, prone position can be used to help improve blood oxygenation.
He also specifically mentioned that when a patient has yellow sputum, it cannot be equated with bacterial infection. The change in sputum color only means that there are a large number of exfoliated inflammatory cells in the airway secretions. When there is no clear evidence of bacterial infection , antimicrobials are not recommended.
Optimum time window for antiviral treatment: three to five days after onset
Cao Bin emphasized that the best time for antiviral treatment is within three to five days of onset, while viral pneumonia caused by the new coronavirus is usually one week after the onset, which has exceeded the best "time window" for antiviral treatment. Do not use antiviral drugs. There is no clinical research to give a positive answer. Some patients may benefit from it. It is necessary to consider basic diseases, oxygenation, and inflammation indicators to stratify patients to refine the research.
Cao Bin cited a series of clinical trial data and summarized the use of several small molecule antiviral drugs that have been marketed: Nematvir/ritonavir, remdesivir, and monupinavir are suitable for patients with high-risk factors Remdesivir is also suitable for patients with severe disease but does not need mechanical ventilation; Ensitrelvir, which has obtained emergency use authorization in Japan, is suitable for non-high-risk mild/moderate patients. Phase III clinical trials have proved that it can Significantly shorten the remission time of core clinical symptoms and significantly reduce the viral load, and have fewer drug interactions than nematevir/ritonavir.
When talking about Azvudine, which has been approved in China, Cao Bin believes that its mechanism and target are not particularly clear at present, and the clinical research results have not yet been published. Compared with the above-mentioned antiviral drugs, the chain of clinical evidence is not sufficient. .
In the question-and-answer session, when asked whether the combination of different types of antiviral drugs is effective for critically ill patients, Cao Bin said frankly that there are only two targets for the domestic new crown antiviral drugs, and no one has studied the combination of the two drugs. To treat the severe new crown.
His tone gradually became agitated, "Antiviral drugs are not magic drugs, they can only inhibit virus replication to a certain extent. What is the concept of severe disease? The virus causes a large number of cell death in the host body, (at this time) antiviral drugs can be used again What's the use...survival and death may be determined when (with or without) antiviral drugs are given to patients. When enough cells die, death is a fate that cannot be changed by antiviral drugs."
Cao Bin said that when intubation is required in severe cases, the patient's chances of survival are small. At present, the protective lung ventilation strategy in the prone position is more recognized.
Vaccination throughout the course, early use of antiviral treatment, and blood oxygen monitoring are all very important and effective means of preventing severe illness.
Be wary of "silent hypoxia" in the elderly
Zhang Wenhong, director of the Infectious Diseases Department of Huashan Hospital Affiliated to Fudan University and director of the National Center for Infectious Diseases, also participated in the live broadcast, bringing a keynote speech on the research progress of anti-influenza drugs.
"The diagnosis and treatment process of influenza pays special attention to vulnerable groups, and all the experience of influenza has been applied to the new crown without exception." Zhang Wenhong said that antiviral treatment for influenza must be within 48 hours of onset to effectively reduce the risk of hospitalization and ICU, while other The team's research shows that the final effect of the new crown treatment is completely different if it is within 3 days, within 5 days or more than 5 days.
Zhang Wenhong and Cao Bin also noticed that it was too late for some elderly patients to be sent to the hospital because they were slow to respond to hypoxia, and they even did not feel chest tightness or dyspnea at all. Hypoxia".
For example, he said that an old man in his nineties was lying motionless in bed, and he had been hypoxic for a long time when the abnormality was discovered.
Especially for the elderly whose children are busy and taken care of by aunts, the risk of this "silent hypoxia" may be higher.
"If hypoxia cannot be corrected within a short period of time, patients can easily develop severe pneumonia." Zhang Wenhong emphasized that the threshold for discovering severe risks must be pushed forward. It is suggested that neighborhood committees or enterprises can give each family with elderly people Get a pulse oximeter.
In addition, he proposed that grass-roots hospitals must actively carry out "on-the-spot treatment", and grass-roots hospitals should be able to provide basic oxygen therapy, small-dose hormones, and prone position ventilation, which will lay a good foundation for hierarchical diagnosis and treatment of the new crown epidemic, and avoid The shortage of medical resources allows high-level hospitals to treat critically ill patients in a timely manner, or even if the higher-level hospitals are run out, patients can return to the grass-roots hospitals to solve the problem.
"A change in mechanism may benefit many people. Doctors at different levels, especially grassroots doctors, can play a greater role." Therefore, he hopes that all hospitals and departments with beds should do a good job in the treatment of new crown patients. and training, especially for doctors in respiratory, infectious and intensive care.
Can people who have immune diseases or use immunosuppressants get the new crown vaccine?
Zhang Wenhong said that there is no need for more hesitation, and the international consensus is that vaccination should be done.
He said that his research team has completed one of China's largest studies on vaccination before or after liver transplantation, conducted corresponding monitoring before and after vaccination, and found that vaccination is safe.
"Although the use of immunosuppressants will reduce the antibody titer after vaccination to a certain extent, this is not a reason not to vaccinate, because the risk of infection will be greater if you do not vaccinate." Zhang Wenhong suggested that such patients When taking a heterologous booster injection, choose a recombinant protein vaccine, which has a lower risk than a live vaccine (adenovirus vaccine), and you should consult with a specialist for details.
Zhang Wenhong said that he is currently preparing a vaccination process with relevant societies for your reference from the perspective of evidence-based medicine.
The Paper reporter Chen Zhuqin