Covid-19 Prevention Handbook (2/3)
2021-02-12 00:12


20. What are the risk factors for pneumonia transmission in the community?

Autumn and winter are popular seasons for respiratory viruses such as influenza. All kinds of infections can occur, especially upper respiratory infections, which can be difficult to distinguish from the early symptoms of COVID-19.

The infection sources of community-acquired pneumonia mainly include patients, their family members, visitors and their living environment. The distribution and outcome of community-acquired pneumonia is related to:

(1) Environmental status: air pollutants, indoor congestion, humidity, indoor hygiene, season, temperature;

(2) Access to and effectiveness of health care services and infection prevention measures to control the spread: vaccines, access to health care facilities and isolation capacity, etc.;

(3) Host factors: age, smoking status, infectious level of the host, immune status, nutritional status, previous infection or associated with other pathogens, and basic physical conditions;

(4) Pathogen characteristics: including transmission mode, infectivity, virulence factors and microbial biomass (inoculation amount).

21. How can community-acquired pneumonia be prevented?

Source control of infection: when patients with acute respiratory diseases cough or sneeze, cover their mouth and nose with their hands or other materials (handkerchiefs, tissues, cloth masks or surgical masks) to reduce the spread of droplets. After contact with respiratory secretions, people should immediately practice hand hygiene and wash their hands frequently.

personal prophylaxis

(1) Reasonable diet, adequate nutrition and oral health can help prevent the occurrence of pneumonia;

(2) Appropriate exercise to improve the immune capacity;

(3) smoking cessation and alcohol restriction, psychological balance;

(4) Maintain indoor ventilation (ventilation can be promoted through natural ventilation and/or exhaust fans;

(5) Vaccination.

22. How to disinfect the indoor air and floor?

(1) Alcohol: alcohol can denaturate and coagulate the protein of bacteria. Skin can be disinfected with 75% medical alcohol.

(2) Steamer: 20 minutes from boiling to achieve the purpose of disinfection, suitable for disinfection of cutlery, clothing and wound gauze.

(3) Boiling: : 100℃ can also make the bacterial protein denaturation, need to be disinfected items need to be soaked in the water. Suitable for tableware, some toys, baby bottles and other small items.

(4) natural ultraviolet ray: natural ultraviolet ray is sunlight, the sterilization effect can not be ignored. Applicable to air, clothing, plush toys, bedding, etc.

(5) air cleaning: keep the indoor air clean, often ventilation is necessary, especially in autumn and winter weather, don't neglect ventilation because of the cold.

(6) potassium permanganate solution: use 5‰ potassium permanganate can disinfect tableware, vegetables and fruits, soak for 1 minute and then rinse again with clean drinking water.

(7) bleaching powder: bleaching powder can cause the enzyme inactivity of bacteria and lead to death, which is a very effective disinfection and sterilization method. Use 1-3% bleach water (bleach powder and water) on tables, chairs, beds, floors, walls, etc., and wipe it with a rag to achieve the purpose of disinfection.

(8) disinfectant: the disinfectant contains chlorine and can be effectively disinfected and sterilized. After being diluted directly, it can be disinfected and sterilized in a plastic pot, but you need to pay attention to avoid food and tableware. Suitable for table, chair, bed, wall, floor and so on.

23. Who is susceptible to novel coronavirus?

The population is generally susceptible. Covid-19 can occur in both immunocompromised and normal populations, and is related to the amount of virus exposure to some extent. If you are exposed to a large amount of the virus at one time, you can get sick even if your immune function is normal. For people with poor immune function, such as the elderly, pregnant women or those with liver and kidney dysfunction, the disease progresses more quickly and is more severe.

Infection depends largely on exposure, not on the fact that people who are resistant to infection are at lower risk. Children have less exposure and are less likely to be infected; Older people, people with chronic diseases, and people with weak immune systems are more likely to be infected with the same exposure.

24. What are the epidemiological features of the Covid-19 outbreak?

Most of the early cases had exposure history in Wuhan South China Seafood Market, and some of the cases were family clusters. There has been human-to-human transmission and infection among health workers, with community transmission evident in Wuhan city.

Novel coronavirus has been lethal, but the mortality rate has not been determined, but its high risk may be lower than SARS virus, in a state of prevention and control, but the flow of population will accelerate the spread, increasing the difficulty of prevention and control.

25. What are the ways in which novel coronavirus is transmitted?

The main modes of transmission are droplet transmission, contact transmission (including self-inoculation by hand contamination), and close transmission of respiratory aerosols of different sizes.

Most of the cases admitted to hospitals in the early stage had a history of exposure to South China Seafood Market in Wuhan, and some of the cases were family clusters with high risk of infection among medical staff. From the present definition of acute respiratory infectious diseases, close droplets transmission should be the main route.

26. Does novel coronavirus pass from person to person?

At present, more than 95% of CoviD-19 cases are related to Wuhan, have been to Wuhan, or come from Wuhan. Judging from the association order of some cluster cases and the infection situation of medical workers, the characteristics of human-to-human transmission is very obvious, and there is a certain range of community transmission.

27. What is droplet transmission?

Droplet: Watery particles generally considered larger than 5um in diameter

Droplet can travel a certain distance (usually 1 m) to the susceptible mucosal surface. Because the droplets are large, they will not be suspended in the air for a long time.

Production of respiratory droplets:

(1) Coughing, sneezing or talking

(2) performing invasive respiratory procedures, such as sputum aspiration or bronchoscopy, endotracheal intubation or piercing cough process such as turning over or back slapping, and CPR, etc;

Pathogens transmitted by droplets: influenza virus, SARS coronavirus, adenovirus, rhinovirus, mycoplasma, group A streptococcus and meningococci (Neisseria), etc.

28. What is airborne transmission?

Aerosol propagation. Airborne particles: Particles less than 5um in diameter that are thought to be infectious after being dispersed over long distances for a long time. Airborne pathogens can also be spread by contact.

Airborne pathogens include: specific airborne: tuberculosis bacilli, aspergillus

Through a variety of ways, but mainly in the air transmission: measles virus, varicella zoster virus

Usually through other routes, but in special cases (such as aerosol-producing procedures -- endotracheal intubation/incision, open airway suction) through airborne transmission: smallpox virus, SARS coronavirus, influenza virus, norovirus, etc.

29. What is contact transmission?

Direct contact: Pathogens are transmitted by direct contact with mucous membranes or skin

Ø blood or blood body fluids by any break in the skin mucous membrane or enter the human body (mainly in the spread of the virus)

Ø caused by direct contact with secretions from containing pathogen transmission, such as scabies indirect contact: infectious pathogens spread through contaminated objects or people

Pathogens of intestinal infections are mostly transmitted through indirect contact:

Ø MRSA (benzene thiazole/methicillin resistant staphylococcus aureus)

Ø VRE (vancomycin resistant enterococcus)


30. What is a Suspected Expositor?

It refers to the processing, sales, handling, distribution or management personnel who have been exposed to wild animals, articles and environment tested positive by Novel Coronavirus, and have not taken effective protection when exposed.

31. What is a Close Contact?

Contact with the case (observed and confirmed case) in any of the following circumstances:

(1) People who live, study, work or have close contact with the case;

(2) Medical personnel, family members or other persons who have similar close contact with the cases without effective protective measures during diagnosis, treatment, nursing and visiting;

(3) The case is the same as other patients and escorts in the ward;

(4) People who were in close contact with the patient on the same vehicle;

(5) Personnel deemed qualified by on-site investigators after investigation and assessment.

32. Why are close contacts placed under medical observation for 14 days?

The incubation period of CoviD-19 is about 7 days on average, with short ones ranging from 2 to 3 days to 10 to 12 days.

At present, it is very necessary to take preventive public health measures, such as strict medical observation, for close contacts. This is a responsible attitude for public health and safety. It is also a common practice of the international community. According to the incubation period of diseases caused by other coronaviruses, the relevant information of this novel coronavirus case and the current prevention and control practice, the medical observation period of close contacts was set as 14 days, and the close contacts were subjected to medical observation at home.

Early detection, early treatment

Early clinical symptoms, case recognition, clinical treatment

33. What are the clinical manifestations of COVID-19 patients?

CoviD-19 is mainly characterized by fever, which can be combined with mild dry cough, fatigue, dyspnea, diarrhea and other symptoms. Symptoms such as runny nose and expectoration are rare.

Half of the patients developed dyspnea a week later, and in severe cases the disease progressed rapidly, with acute respiratory distress syndrome, septic shock, refractory metabolic acidosis, and haemorrhagic dysfunction occurring within days. Some patients with mild onset symptoms, but no fever. The prognosis of most patients is good, a few patients are in critical condition, or even death.

Laboratory examination: in the early stage of the disease, the total number of white blood cells is normal or decreased, the lymphocyte count is reduced, some patients appear liver enzyme, myoenzyme and myoglobin increase. C-reactive protein and erythrocyte sedimentation rate were elevated in most patients, and procalcitonin was normal. In severe cases, the D-dimer was elevated.

34. Are you familiar with the laboratory tests of Covid-19?

Novel coronavirus can be identified by real-time fluorescence RT-PCR. Upper and lower respiratory tract samples, such as bronchial or alveolar lavage fluid and deep cough sputum, were collected from each case. Serum samples were also collected at the beginning of the disease and 14 days after the disease onset.

In the early stage of the disease, the total number of white blood cells is normal or decreased, the lymphocyte count is reduced, some patients appear liver enzyme, myoenzyme and myoglobin increase. C-reactive protein and erythrocyte sedimentation rate were elevated in most patients, and procalcitonin was normal. In severe cases, the D-dimer was elevated.

35. Do you know the chest imaging features of patients with COVID-19?

At the early stage, there were multiple small patches and interstitial changes, with obvious lung extras, and then developed into multiple ground glass shadows and infiltrating shadows in both lungs. In severe cases, lung consolidation or even "white lung" could occur. Pleural effusion was rare.

36. Do you know how to identify and observe COVID-19 cases in clinical practice?

At the same time comply with the following two

(1) Epidemiological history: Travel history in Wuhan, or direct or indirect contact with relevant markets in Wuhan, especially farmers' markets, within two weeks before the onset of disease.

(2) Clinical manifestations: fever; It had the imaging characteristics of viral pneumonia. In the early stage of the disease, the total number of white blood cells is normal or decreased, or the lymphocyte count is reduced; After 3 days of standardized antimicrobial therapy (according to the Guidelines for the Diagnosis and Treatment of Chinese Adult Community Acquired Pneumonia (2016 Edition) issued by the Respiratory Society of Chinese Medical Association and the Guidelines for the Diagnosis and Treatment of Children Community Acquired Pneumonia (2019 Edition) issued by the National Health Commission, there was no significant improvement or progressive deterioration in the condition.

37. Do you know how to diagnose a case of Covid-19 clinically?

On the basis of observation cases, the pathogenic diagnosis can be made by collecting the respiratory tract samples such as sputum and pharyngeal swabs for viral nucleic acid gene detection.

38. How to diagnose critical cases clinically?

Critical case refers to the patient's vital signs are unstable, the condition changes rapidly, more than two organ system function is unstable, decline or failure of the disease development may endanger the patient's life.

39. What diseases does Covid-19 need to be differentiated from?

(1) Bacterial pneumonia

The common symptoms are cough, expectoration, or aggravation of the original respiratory symptoms, and purulent or bloody sputum, with or without chest pain. It is generally not contagious and is not a contagious disease.


This will be found coronavirus and and MERS SARS coronavirus is comparable to the belong to the coronavirus family, but the genetic evolution analysis shows they belong to different branch of the group, it is not SARS, nor MERS virus, the virus gene sequences of differences is larger, the current survey, the interpersonal communication ability and pathogenic virus are weaker than SARS.

40. What should you do if you are notified by the CDC that you are a close contact?

According to the requirements for medical observation that occupy the home, don't panic, don't go to work, don't go out, do a good job in self condition observation, community doctors follow-up regularly, if appear abnormal clinical symptoms such as fever, cough, report to the local institution of disease prevention and control, under the guidance to the designated medical institutions for screening, diagnosis and treatment, etc.

Do you know why influenza caused by influenza virus is easy to spread?

Influenza viruses are spread mainly through airborne droplets, contact between susceptible people and infected people, or through contact with contaminated materials. Generally, autumn and winter are the peak season. Human influenza is mainly caused by influenza A virus and influenza B virus. Influenza A viruses often undergo antigenic variation, and can be further divided into H1N1, H3N2, H5N1, H7N9 and other subtypes. When a new influenza virus subtype appears, the population generally lacks immunity to it, so it is easy to cause a pandemic.

Do you know the similarities and differences between SARS and Covid-19?

Novel coronavirus, MERS coronavirus, SARS coronavirus all belong to coronavirus, but they are not the same, the former two infectivity and "virulence" are not as big as SARS coronavirus, the severity is different.

43. What are the early symptoms of COVID-19? How to identify and judge?

General symptoms:

Fever, fatigue, dry cough, gradually appear dyspnea, some patients with mild onset symptoms, but no fever.


Acute respiratory distress syndrome, septic shock, refractory metabolic acidosis, haemorrhagic dysfunction

Most of the patients have moderate and mild disease with good prognosis, while a few patients are in critical condition or even die.

44. Is there any specific drug or vaccine for the treatment of CoviD-19?

Currently, there is no effective antiviral drug for novel coronavirus, and the treatment is mainly symptomatic and supportive. Avoid blind or inappropriate antimicrobial therapy, especially in combination with broad-spectrum antimicrobial agents.

There is no vaccine available for the new disease. It could take years to develop a new vaccine.

45. Can rapid tests now identify Novel Coronavirus infection?

On the basis of meeting the criteria of suspected cases, the positive nucleic acid of 2019-NCoV was detected by real-time fluorescence RT-PCR in sputum, pharyngeal swab and lower respiratory tract secretions.

46. What should I do if I think I am infected with Novel Coronavirus and need clinical treatment?

If you think you are infected with Novel Coronavirus, seek medical attention immediately.

WHO has issued guidelines for the clinical management of severe acute respiratory infections caused by suspected novel coronavirus infection. There is currently no specific treatment for disease caused by novel coronavirus. But many health problems can be treated symptomatic and therefore need to be treated according to the patient's clinical situation. In addition, assisted care for infected people can be very effective.

47. How to select the treatment site for COVID-19?

Patients should be isolated and treated in hospitals with effective isolation conditions and protection conditions, and critical cases should be admitted to ICU for treatment as soon as possible.

48. How is Covid-19 treated?

1. Rest in bed, strengthen supportive treatment, pay attention to water and electrolyte balance, and maintain internal environment stability

2. Monitor all indicators according to the condition.

3. According to the change of oxygen saturation, timely delivery of effective oxygen therapy measures

4. Antiviral therapy: There are no effective antiviral drugs at present.

5. Antimicrobial drug treatment: strengthen bacteriological monitoring, and apply antimicrobial drugs in time when there is evidence of secondary bacterial infection.

6. Chinese medicine treatment: dialectical treatment according to the symptoms.

49. What are the criteria for clinical release and discharge?

The first indicator of discharge was stable condition and improved fever. Second, lung imaging improved significantly, without organ dysfunction. Patients with stable breathing, clear consciousness, normal communication, normal diet, body temperature back to normal for more than 3 days, significantly improved respiratory symptoms, two consecutive negative respiratory pathogenic nucleic acid tests (at least 1 day interval), can be discharged from hospital or transferred to the corresponding department for treatment of other diseases according to the condition.

50. What are the transport principles for transporting patients?

Patients should be transported in special vehicles, and do a good job of personal protection and vehicle disinfection.

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