The current critical period for COVID-19 prevention and control is also the season of high influenza incidence. When COVID-19 encounters the flu season, how to distinguish COVID-19 from flu and common cold? How to correctly understand COVID-19 and take scientific and effective protective measures? Recently, Xinhuanet launched the special topic “War” epidemic “Experts said”, the 15th issue invited Nanchang University Second Affiliated Hospital Chief Physician Professor Kuang Jiulong to share with us related topics of COVID-19.
Xinhuanet: What caused COVID-19?
Kuang Jiulong: At the end of 2019, a number of unexplained pneumonia cases were found in Wuhan. After identification of the pathogen and investigation of its etiology, it was confirmed that it was caused by a new type of coronavirus infection. The World Health Organization officially named this disease as “COVID-19” (Corona Virus Disease 2019), which China calls a new type of coronavirus pneumonia, is referred to as “COVID-19”. Coronavirus is a type of virus that exists in nature. It is named because it looks like a crown under an electron microscope. So far, coronaviruses only infect humans and vertebrates, and it can cause respiratory, digestive, and nervous system diseases in humans and vertebrates.
When it comes to coronaviruses, you might think of SARS in 2003 and MERS, which was prevalent in the Middle East. They are also coronaviruses, but COVID-19 is different from SARS and MERS. Although they have some homology, they have less than 80% similarity, so they are not the same virus.
Xinhuanet: How did COVID-19 spread?
Kuang Jiulong: Coronaviruses can be transmitted from person to person, which is determined by the laws of virus biology. At present, epidemiological investigations have confirmed that the main route of transmission is respiratory droplets, which are transmitted through cough, sneeze and close contact, especially It is the contact with the patient and the source of infection without safety protection, such as touching the surface of a contaminated object, and then touching the mouth, nose, eyes, etc. with the contaminated hand.
In addition, aerosol transmission may occur in long-term exposure in a relatively closed environment, but it is not the main route of transmission. Despite the detection of the virus in the stool, the spread of the digestive tract currently requires further observation and confirmation of epidemiology.
It is precisely because the disease can be transmitted from person to person, so to control the disease, we must first interrupt the transmission route, so that it does not have the conditions for transmission from person to person, isolate the source of infection, and cut off the transmission route to effectively control the spread of the disease.
Xinhuanet: Who is vulnerable to COVID-19?
Kuang Jiulong: People who have close contact with suspected cases and confirmed cases. The first category is close contact with people who live, study and work with suspected and confirmed cases; the second category is diagnosis, treatment, nursing, visiting cases, such as medical staff without effective protective measures; the third category, other patients with cases and Escorts; fourth, people who are on the same vehicle as the case and have close contact; fifth, people who are assessed by investigators as eligible after investigation.
To determine whether it is a close contact, you must analyze the possibility of infection and comprehensively consider multiple factors such as the method of contact, the degree of contact, and the clinical manifestations of the case to determine whether it is a close contact.
Xinhuanet: What damage will COVID-19 cause to the human body?
Kuang Jiulong: COVID-19 originated in the lungs, and it has many similarities with influenza. After infection, patients may develop symptoms such as cough, sneezing, and fever, and eventually develop pneumonia. There are three stages, the first stage is the virus replication stage, the second stage is the lung damage caused by the overreaction of the immune system, and the third stage is the repair.
First, the lung is the primary point of infection with COVID-19. This disease usually attacks the lungs in three stages: the viral replication phase, the immune system overreaction phase, and the lung injury phase. In the early stages of infection, the COVID-19 virus quickly invades human lung cells. She developed bilateral lung pneumonia with symptoms of shortness of breath. Then, in the second stage, the immune system works. After the virus invades, our bodies will fight, inject immune cells into the lungs, clear the damage, and repair the lung tissue. Under normal circumstances, the inflammatory process is strictly controlled and limited to the infected area. But sometimes the immune system gets out of control, and immune cells kill everything, including healthy tissue. In the third stage, lung injury will continue and eventually lead to respiratory failure. Even without death, some patients suffer from permanent lung damage.
Secondly, “cytokine storm”, cytokines such as TNF-α, IL-1, etc. refer to the proteins used by the immune system to issue alarms. They are responsible for focusing the immune system to the site of infection. The immune cells then kill the infected tissue and rescue the rest of the body. The daily work of the immune system is to clear the infection and rely on the immune system to protect itself when the body encounters a threat. “Cytokine storm” refers to the phenomenon that a variety of cytokines in body fluids are rapidly and massively produced after the body is infected with microorganisms. If the immune system is activated to the limit or loses control, it will harm the host, extreme Immune attacks cause severe lung damage, leading to acute respiratory failure and multiple organ failure. In addition to the characteristics of lung lesions, at least one other symptom appears: increased liver enzymes, decreased white blood cell and platelet counts, decreased blood pressure, acute kidney injury, myocardial damage, cardiac arrest, that is, the immune system not only attacks infected cells, Not even health organizations missed it.
Finally, there is multiple organ damage. After the cytokine storm is generated, the cytokine storm caused by the induced inflammation will enter the circulatory system, causing systemic problems in multiple organs, and renal failure, myocardial damage, heart failure, and liver function damage Coagulation dysfunction.
Xinhuanet: How to tell if you have COVID-19 if you have respiratory symptoms?
Kuang Jiulong: Based on the current epidemiological investigation, the incubation period is 1-14 days, mostly 3-7 days. Fever, fatigue, dry cough are the main symptoms. A few patients are accompanied by occlusion, runny nose, sore throat, myalgia and diarrhea. Severe patients develop dyspnea or hypoxemia in the first week after onset, and severe patients rapidly progress to acute respiratory failure (acute respiratory distress syndrome), sepsis, and multiple organ failure. It is worth noting that some patients have mild onset symptoms, no fever, and no pneumonia. Most patients are mild. The prognosis is good, and a few patients are critically ill and even die.
Early clinical manifestations, such as fever, fatigue, and dry coughing, do not imply infection. However, if there are symptoms of acute respiratory infections such as fever (underarm temperature ≥ 37.3C), cough, shortness of breath, and history of travel or residence in Wuhan, or patients who have been exposed to fever with respiratory symptoms from Wuhan within 14 days before onset, If there is a small-scale clustered disease, it should be checked, diagnosed and treated at the local designated medical institution.
Xinhuanet: How to distinguish between flu and COVID-19?
Kuang Jiulong: The clinical symptoms of colds are mainly nasal congestion, runny nose, and sneezing. The symptoms are mild. There were no obvious symptoms such as fever, headache, joint pain, general discomfort, and physical strength, appetite and so on. People with colds usually have severe upper respiratory symptoms, general systemic symptoms are generally mild, and are generally not life-threatening. Symptoms can be effectively improved after taking medicine, and they can usually heal themselves after about 7 days.
Influenza is a respiratory infection caused by an influenza virus infection, which not only causes upper respiratory tract infections, but also lower respiratory tract infections. The two seasons of winter and spring are also seasons of influenza epidemic, which can generally be divided into influenza A and influenza B. Influenza patients are usually more acute, with severe symptoms, such as high fever, cough, and sore throat. Most of them will have fever symptoms, and the temperature can rise above 39 degrees, accompanied by headaches, general soreness, severe systemic symptoms, and relatively mild respiratory symptoms.
The early symptoms of new coronavirus pneumonia are only a little fever, cough, chills and physical discomfort, but as the course of the disease, not only fever and cough symptoms, but also fatigue symptoms, about 50% after infection with new coronavirus Most patients had chest tightness and dyspnea after 3 to 5 days. Severe cases progress rapidly to acute respiratory distress syndrome (ARDS), septic shock, difficult to correct metabolic acidosis, and coagulopathy. After one week, the course of the disease will gradually worsen, and pneumonia, or even severe pneumonia, will occur, resulting in accelerated breathing, respiratory failure, multiple organ damage, and even death.
Now is the high incidence of colds and flu, so be careful to judge your condition. For judging the epidemic situation of respiratory infectious diseases, special attention should be paid to (1) whether there is a history of travel or residence in Wuhan and surrounding areas or other communities with case reports within 14 days before the onset of disease; (2) whether it is related to the new type of coronary disease within 14 days before the onset of Virus-infected persons (positive nucleic acid test, that is, confirmed patients) have a history of contact; (3) Whether they have been exposed to patients from Wuhan and surrounding areas, or from patients with fever or respiratory symptoms in the case-reporting community within 14 days before the onset of illness; (4) ) Whether there is a clustered disease.
Xinhuanet: What are the vulnerable groups of COVID-19?
Kuang Jiulong:
1. Older people
Concerning the current “age distribution of the population infected with the COVID-19 virus”, the proportion of the “elderly group” is the largest, and the prevalence and mortality of elderly patients belong to the “largest share of the age distribution”. Relatively speaking, the physical capacity of the elderly population is in a declining stage, and their organ capacity and immunity are lower than those of young people, so they are more likely to be “defeated by the COVID-19 virus”, and their risk of disease will naturally be higher.
2. Crowds in “populated places”
For the “new coronavirus”, the transmission mode is more “droplet” infection. Therefore, in places with a large number of people, the risk of infection with the “COVID-19 virus” is naturally higher. In real life, many people are “unwilling to be lonely.” They are always used to staying and playing in places with many people. Some people may also have special reasons for work. However, it is more likely to occur in closed, airless and densely crowded places. In the case of “virus infection”, there are more people and more viruses; the smaller the space, the larger the number of virus units, so the risk of infection will naturally increase.
3. People with “certain underlying diseases”
According to data reports from official media, it was found that a large part of the publicly reported “severe new coronavirus pneumonia” patients belonged to patients with respiratory diseases, hypertension, diabetes, cirrhosis and other problems; there were serious underlying diseases The group of people also belongs to the “COVID-19 susceptible group” and needs to be paid special attention.
4.People with bad living habits and low autoimmunity
I do n’t like exercise in my daily life. I usually sit, smoke, and drink for a long time. It is easy to catch a cold from people nearby, indicating that “resistance is relatively low”. This group of people is also susceptible to the COVID-19 virus. crowd. This group of people needs to adjust their lifestyles and eating patterns, exercise more, eat and sleep in a balanced arrangement, and strengthen their defenses against viruses. In addition, children, pregnant women, and medical personnel who contact patients are also “susceptible groups of COVID-19 virus.” These people need to “focus on prevention and control” in their lives to avoid being attacked by the epidemic.