Journal of

Clinical Medicine

Review
Characteristics of and Public Health Responses to the
Coronavirus Disease 2019 Outbreak in China
Sheng-Qun Deng and Hong-Juan Peng *
Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of
Public Health, Southern Medical University, Guangzhou 510515, China; dengshengqun@163.com
* Correspondence: hongjuan@smu.edu.cn; Tel.: +86-20-61648526




Received: 30 January 2020; Accepted: 14 February 2020; Published: 20 February 2020


Abstract: In December 2019, cases of unidentified pneumonia with a history of exposure in the
Huanan Seafood Market were reported in Wuhan, Hubei Province. A novel coronavirus, SARS-CoV-2,
was identified to be accountable for this disease. Human-to-human transmission is confirmed, and
this disease (named COVID-19 by World Health Organization (WHO)) spread rapidly around the
country and the world. As of 18 February 2020, the number of confirmed cases had reached 75,199
with 2009 fatalities. The COVID-19 resulted in a much lower case-fatality rate (about 2.67%) among
the confirmed cases, compared with Severe Acute Respiratory Syndrome (SARS) and Middle East
Respiratory Syndrome (MERS). Among the symptom composition of the 45 fatality cases collected
from the released official reports, the top four are fever, cough, short of breath, and chest tightness/pain.
The major comorbidities of the fatality cases include hypertension, diabetes, coronary heart disease,
cerebral infarction, and chronic bronchitis. The source of the virus and the pathogenesis of this disease
are still unconfirmed. No specific therapeutic drug has been found. The Chinese Government has
initiated a level-1 public health response to prevent the spread of the disease. Meanwhile, it is also
crucial to speed up the development of vaccines and drugs for treatment, which will enable us to
defeat COVID-19 as soon as possible.

Keywords: coronavirus; pneumonia; 2019-nCoV; clinical characteristics; diagnosis; prevention and

control; treatment; public health; COVID-19; SARS-CoV-2

1. Introduction
In December 2019, a cluster of pneumonia of unknown etiology was detected in Wuhan City, Hubei
Province of China. The first 27 reported cases were all related to Huanan Seafood Wholesale Market,
which sells aquatic products, live poultries, and wild animals [1]. The first batch of cases identified
later showed no exposure or even no relation to Huanan Wholesale Market, and the human-to-human
transmission was confirmed; moreover, nosocomial infections were reported in some health care
workers [2–4]. The Chinese Center for Disease Control and Prevention (CDC) and Chinese health
authorities later identified and announced that a new coronavirus (2019-nCoV) was accountable for
the outbreak of this pneumonia in Wuhan [5]. Thereafter, this disease was named Coronavirus Disease
2019 (COVID-19) by World Health Organization (WHO), and the causative virus was designated
as SARS-CoV-2 by the International Committee on Taxonomy of Viruses [6]. Within one and a half
months, as of midnight of 18 February 2020, the novel coronavirus pneumonia (COVID-19) had spread
from Hubei to 34 provinces in China and another 25 countries, resulting in 75,199 confirmed cases
with 2009 deaths (Table 1) [7]. At present, the number of cases is increasing rapidly in China and even
around the world, which is a big threat to public health. Thirty-one provinces of China have initiated a
level-1 public health response. The aim of this article is to provide a timely review of the characteristics

J. Clin. Med. 2020, 9, 575; doi:10.3390/jcm9020575 www.mdpi.com/journal/jcm

J. Clin. Med. 2020, 9, 575 2 of 10

of the COVID-19 outbreak including the epidemiology, pathogenicity, clinical features, and measures
of treatment, prevention, and control for this disease.

2. The Epidemiology of COVID-19

On 31 December 2019, Wuhan Municipal Health Commission reported a number of unknown
pneumonia cases related to Huanan Seafood Wholesale Market, 27 cases were hospitalized, seven
of which were in serious condition [1]. On 5 February 2020, Wuhan Municipal Health Committee
reported that 59 cases of viral pneumonia with unknown etiology were detected in Wuhan, including
seven severe cases, but no clear evidence was found for “human-to-human” transmission [8]. On Jan
11, Wuhan Municipal Health Committee issued a new report confirming that the pathogen of the viral
pneumonia of unknown cause was initially determined as a new coronavirus [9]. On 20 February
2020, it was officially confirmed that “human-to-human” transmission and nosocomial infection had
occurred [2,3].

Table 1. The key information about the coronavirus infection outbreaks.

Total Confirm Cases Countries

Median Age Number Case-Fatality
Coronavirus Infection Outbreak Female Reported References
Male (%) (Years Old) of Deaths Rate (%)
(%) Cases

COVID-19 75,199 2.67 [10]

55.5 * 2009 26
(November 2019–18 February 2020) 32 * 67 * 11.0 * [4]
SARS 8098
41.3 774 9.60 26 WHO [11]
(November 2002–July 2003) 53.1 46.9
MERS 2494
52.8 858 34.4 27 WHO [12]
(April 2012–November 2019) 26.3 73.7
COVID-19: coronavirus disease 2019; SARS: severe acute respiratory syndrome; MERS: Middle East respiratory
syndrome; WHO, World Health Organization. * Data are from reference [4].

Since 16 February 2020, the cumulative COVID-19 case number increased quickly; meanwhile, the
daily emerging case number increased steadily to 3886 on 4 February 2020, and then fluctuated to 2015
on 11 February 2020. The fatality cases number increased steadily to 2004 cases on 18 February 2020.
The cumulative and daily emerged cases number jumped to 59,804 and 15,152, respectively, on 12
February 2020 (Figure 1). This fierce growth of cumulative and daily emerged cases number in one day
is due to the improvement of diagnosis standard for confirmed cases in Hubei province, in which the
suspected cases with pneumonia imaging characteristics are categorized as clinical diagnosis cases.
As a result, the patients can receive standard treatment as soon as possible. All data are from the
National Health Commission of the People’s Republic of China [10].
The COVID-19 resulted in much lower mortality (about 2.67% up-to-date) among the confirmed
cases, compared with Severe Acute Respiratory Syndrome (SARS) at 9.60% (November 2002–July
2003) and Middle East Respiratory Syndrome (MERS) at 34.4% (April 2012–November 2019) (Table 1).
The median ages for the patients of COVID-19, SARS, and MERS are 55.5, 41.3, and 52.8 years old,
respectively. COVID-19 and MERS patients share similargender composition of females (32%) and
males (67%), but SARS patients show almost the same proportion of males (46.9%) and females (53.1%).
According to the “Diagnosis &Treatment Scheme for Novel Corona Virus Pneumonia (Trial) 6th
Edition”, the source of infection is majorly the COVID-19 patients, even the asymptomatic patients
can also be the source of infection. The transmission way is majorly through respiratory droplets and
contacting. People are generally susceptible to this virus.
respectively, on 12 February 2020 (Figure 1). This fierce growth of cumulative and daily emerged
cases number in one day is due to the improvement of diagnosis standard for confirmed cases in
Hubei province, in which the suspected cases with pneumonia imaging characteristics are
categorized as clinical diagnosis cases. As a result, the patients can receive standard treatment as
soon as possible. All data are from the National Health Commission of the People’s Republic of
J. Clin. Med. 2020, 9, 575 3 of 10
China [10].

Figure 1. Daily cumulative/emerged number of confirmed cases and fatal cases of Coronavirus Disease
Figure 1. Daily cumulative/emerged number of confirmed cases and fatal cases of Coronavirus
2019 (COVID-19) in Mainland China. As of 18 February 2020, the total number of confirmed cases and
Disease 2019 (COVID-19) in Mainland China. As of 18 February 2020, the total number of confirmed
deaths reached 74,185 and 2004, respectively. Since 16 February 2020, the total number of confirmed
cases
casesand deaths quickly;
increased reached the
74,185 and
daily 2004, respectively.
emerging Sincesteadily
cases increased 16 February 2020,
to 3886 the total number
on February of
4, and then
confirmed cases increased quickly; the daily emerging cases increased steadily to 3886 on February
fluctuated to 2015 on 11 February 2020; the fatality cases number increased slowly to 2004 cases on 4,
and then fluctuated to 2015 on 11 February 2020; the fatality cases number increased slowly
18 February 2020. The cumulative and daily emerged cases number jumped to 59,804 and 15,152, to 2004
cases on 18 February
respectively, 2020. The
on 12 February cumulative and daily emerged cases number jumped to 59,804 and
2020.
15,152, respectively, on 12 February 2020.
3. Pathogenic Characteristics of Coronavirus
Coronavirus is a single strand positive RNA (+ssRNA) virus, belonging to order Nidovirales,
family Coronaviridae, and subfamily Orthocoronavirinae [13]. According to the characteristics of
serotype and genome, the coronavirus subfamily is divided into four genera: α, β, γ, and δ [14]. There
are six kinds of coronaviruses known to infect humans, including 229E and NL63 of α genus [15,16],
OC43, HKU1, Middle East respiratory syndrome-associated coronavirus (MERSr-CoV), and severe
acute respiratory syndrome-associated coronavirus (SARSr-CoV) of β genus [16,17]. The coronavirus
isolated from the lower respiratory tract of patients with unidentified pneumonia in Wuhan is a
new type of coronavirus (SARS-CoV-2) belonging to genus β, and subgenus sarbe [5]. SARS-CoV-2
is different from the zoonotic MERSr-CoV and SARSr-CoV and becomes the seventh coronavirus
to infect humans [5]. The phylogenetic analysis of the coronaviruses based on full-length genome
sequences shows that SARS-CoV-2 has the smallest genetic distance from bat coronavirus, but only
about 45%–90% similarity with SARSr-CoV, and a lower similarity of 20%–60% with MERSr-CoV [18].
Therefore, a bat is probably the original host of SARS-CoV-2, although the intermediate host may still
exist in the process of transmission from bats to human beings.
Coronavirus has an envelope, the particles are round or oval, often pleomorphic, with a diameter
of 50–200 nm [18]. S protein is located on the surface of the virus and forms a rod-shaped structure.
As one of the main antigenic proteins of the virus, the S protein gene is the main target used for
typing [19]. Xu et al. also reported that SARS-CoV-2 S-protein supports a strong interaction with
human angiotensin-converting enzyme 2 (ACE2) molecules, which means that the virus poses a
significant public health risk for human transmission by the S-protein–ACE2 binding pathway [18].
The knowledge of the physical and chemical characteristics of coronaviruses mostly comes from
the study of SARS-CoV and MERS-CoV. The coronaviruses are sensitive to heat and can be killed at
J. Clin. Med. 2020, 9, 575 4 of 10

56 ◦ C for 30 min. In addition, ether, 75% ethanol, chlorine disinfectant, peracetic acid, and chloroform
can effectively inactivate the virus, but not chlorhexidine [20].

4. Clinical Characteristics of COVID-19

4.1. Clinical Manifestations

According to the “Diagnosis & Treatment Scheme for Novel Coronavirus Pneumonia (Trial) 6th
Edition” enacted by the National Health Commission of the People’s Republic of China on 19 February
2020, the incubation time after exposure is about 1–14 days [20]. Fever, fatigue, and a dry cough are the
main manifestations. Nasal obstruction, runny nose, and other upper respiratory symptoms are rare.
About half of the patients developed dyspnea one week later, and severe cases developed rapidly into
acute respiratory distress syndrome, septic shock, hard-to-correct metabolic acidosis, and coagulation
dysfunction. Severe and critical patients may present moderate to low fever, or even no obvious
fever. Some patients have mild onset symptoms, no fever, and mostly recovered after one week. Most
patients have a favorable prognosis, although some patients are left in a critical condition, or do not
survive. The aged patients and the patients with basic diseases have worse prognosis. Children cases
are relatively mild.

4.2. Laboratory Examination

In the early stages of the disease, the total number of leukocytes in peripheral blood is normal
or decreased, the lymphocyte count is decreased, and some patients present elevated levels of liver
enzyme, muscle enzyme, and myoglobin; some severe cases present elevated troponin level. Most
patients show elevated C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and normal
procalcitonin. In severe cases, the patients present with increased D-dimer and progressively decreased
peripheral blood lymphocyte [20]. Compared with non-ICU patients, the plasma levels of IL2, IL7,
IL10, GSCF, IP10, MCP1, MIP1a, and TNF-α were higher in ICU patients [21].

4.3. Chest Imaging

All patients suffered from pneumonia, and chest CT scans showed shadows in the lung [20]. In the
early stages of the disease, patients present with multiple small patch shadows and interstitial changes,
especially in the extrapulmonary zone. It further progresses to multiple ground glass shadows and
infiltrative shadows in both lungs. In severe cases, lung consolidation may occur, but pleural effusion
is rare [20].
To provide more information about the disease for the treatment in clinics, we collected detailed
information about the fatal cases released by official channels. A total of 41 fatal cases were used to reveal
the symptoms of the deaths, showing the symptom composition of fever (80.5%), cough (56.1%), short
of breath (31.7%), chest tightness/pain (24.4%), fatigue (22.0%), dyspnea (12.2%), dizziness/headache
(4.9%), general pain (7.3%) and chills (4.9%) (Figure 2). A total of 26 cases with fatalities were used to
disclose the dangerous comorbidities, showing that the major comorbidities are hypertension (53.8%),
diabetes (42.3%), coronary heart disease (19.2%), cerebral infarction (15.4%), chronic bronchitis (19.2%)
and Parkinson’s disease (7.7%) (Figure 2). Chen N et al. reported that, among 99 confirmed cases,
the common symptoms are fever (83%), cough (82%), bilateral pneumonia (75%), short of breath
(31%), muscle ache (11%), confusion (9%), headache (8%), sore throat (5%), rhinorrhoea (4%), chest
pain (2%), diarrhoea (2%), and nausea and vomiting (1%) [4]. Huang C et al. reported that, among
41 confirmed cases, the symptom composition is as follows: pneumonia (100%), fever (98%), cough
(76%), lymphopenia (63%), Dyspnea (55%), fatigue (44%), sputum production (28%), headache (8%),
hemoptysis (5%), and diarrhea (3%); and the underlying diseases included diabetes (20%), hypertension
(15%), and cardiovascular disease (15%) [21]. Though the symptom compositions reported for the
confirmed cases are similar to that of the fatality cases we collected, the percentages of hypertension,
diabetes, and coronary heart diseases are much higher among the fatality cases than among the
J. Clin. Med. 2020, 9, 575 5 of 10

confirmed cases. This may indicate that the comorbidities probably are important factors resulted in
death of COVID-19
J. Clin. Med. patients.
2020, 9, x FOR PEER REVIEW 5 of 10

Figure 2.2. Clinical symptoms and comorbidities

Figure comorbidities of the the patients
patients died
died of
of COVID-19.
COVID-19. (A) Among 41 41
cases
cases with
with fatalities,
fatalities, the
the symptoms
symptoms include
include fever
fever (80.5%),
(80.5%), cough (56.1%), shortness of breath (31.7%),
chest
chesttightness/pain
tightness/pain(24.4%),
(24.4%),fatigue
fatigue(22.0%), dyspnea
(22.0%), dyspnea(12.2%), dizziness/headache
(12.2%), (4.9%),
dizziness/headache general
(4.9%), pain
general
(7.3%), and chills (4.9%). (B) Among 26 cases with fatalities, the major comorbidities
pain (7.3%), and chills (4.9%). (B) Among 26 cases with fatalities, the major comorbidities are are hypertension
(53.8%), diabetes
hypertension (42.3%),
(53.8%), coronary
diabetes heart disease
(42.3%), coronary(19.2%),
heart cerebral
disease infarction (15.4%),infarction
(19.2%), cerebral chronic bronchitis
(15.4%),
(19.2%),
chronic and Parkinson’s
bronchitis (19.2%),disease (7.7%). The case
and Parkinson’s information
disease (7.7%). Theis from
case reports released
information by different
is from reports
provincial
released by Health Commissions,
different provincial including the National including
Health Commissions, Health Commission (theHealth
the National links are shown in
Commission
Supplementary Data in
(the links are shown 1). Supplementary Data 1).

5. Diagnosis of COVID-19
5. Diagnosis of COVID-19
The diagnosis was based on a set of clinical criteria recommended by the National Health
The diagnosis was based on a set of clinical criteria recommended by the National Health
Commission of the People’s Republic of China and the National Administration of Traditional Chinese
Commission of the People’s Republic of China and the National Administration of Traditional
Medicine [20].
Chinese Medicine [20].
5.1. Suspected Cases
5.1. Suspected Cases
The cases comply with any item of A and any two items of B, or with 3 items of B as follows. (A)
The cases comply
Epidemiological history:with anytwo
within itemweeks
of A and any
before two items
disease of1.B,have
onset, or with 3 items
a history ofof B as or
travel follows. (A)
residence
Epidemiological history: within two weeks before disease onset, 1. have a history
in the district with case report; 2. have contacted the patients positive with nucleic acid detection;of travel or
residence
3. in the district
have contacted with
with the case report;
patients 2. have
with fever contacted the
and respiratory patients from
symptoms positive
the with nucleic
district acid
with case
detection; 3. have contacted with the patients with fever and respiratory symptoms from the
report; 4. disease onset in clustering. (B) Clinical manifestations: 1. Have fever and/or respiratory tract district
with case report;
symptoms; 2. Have4.pneumonia
disease onset
with inimage
clustering. (B) Clinical
characteristics manifestations:
mentioned above; 3.1.InHave
earlyfever
stageand/or
of the
respiratory
disease, havetract symptoms;
normal 2. Have
or decreased pneumonia
total number ofwith image characteristics
leukocytes, mentioned count.
or decreased lymphocyte above; 3. In
early stage of the disease, have normal or decreased total number of leukocytes, or decreased
lymphocyte
5.2. Confirmedcount.
Cases
The unconfirmed
5.2. Confirmed Cases cases met the criteria of the suspected cases and are identified positive with
SARS-CoV-2 RNA, by real-time RT-PCR or gene sequencing, from the sputum, throat swab, lower
The unconfirmed
respiratory cases
tract secretion, or met
otherthe criteriacollected
samples of the suspected cases and are identified positive with
from patients.
SARS-CoV-2 RNA, by real-time RT-PCR or gene sequencing, from the sputum, throat swab, lower
respiratory tract secretion, or other samples collected from patients.
J. Clin. Med. 2020, 9, 575 6 of 10

5.3. Clinical Typing of the Confirmed Cases

Mild cases: have mild symptoms, no pneumonia manifestation in chest image;
Common cases: have fever, respiratory symptoms, and pneumonia manifestation in chest image;
Severe cases: comply with any item of the follows. (A) dyspnea, respiratory rate ≥30 times/min;
(B) at resting state, finger oxygen saturation ≤ 93%; (C) PaO2/FiO2 ≤ 300 mmHg (1mmHg = 0.133 kPa,
PaO2 : arterial partial pressure of oxygen, FiO2 : fractional concentration of inspired oxygen);
Critical cases: comply with any item of the follows. (A) show respiratory failure and mechanical
ventilation is required; (B) present with shock; (C) combine with other organ failure needing Intensive
Care Unit (ICU) monitoring and treatment; (D) chest imaging shows multilobe lesions or progress of
lesion focus within 48 h ≥ 50%; (E) combine with other clinical conditions requiring hospitalization.

6. Treatment of COVID-19

6.1. Treatment Area Decision According to the Disease Severity

Suspected and confirmed cases should be treated in isolation in hospitals with effective isolation
and protective conditions. The suspected cases should be isolated in a single room, and the confirmed
cases can be accepted in the same room. Critical cases should be treated in ICU as soon as possible.

6.2. General Treatment

A. Bed rest, strengthen supportive treatment, ensure sufficient energy; pay attention to
water-electrolytes balance and maintain the stability of the internal environment; closely
monitor vital signs and finger oxygen saturation, and so on.
B. Monitor the blood routine, urine routine, C-reactive protein (CRP) and health indications (liver
enzyme, myocardial enzyme, renal function, etc.), coagulation function, arterial blood gas
analysis if necessary, and recheck chest imaging.
C. According to the change of oxygen saturation, give effective oxygen therapy in time, including
oxygen given by nasal catheter or mask. If necessary, apply high flow oxygen therapy via the
nose, noninvasive or invasive mechanical ventilation, and so on.
D. Antiviral treatment: no effective antiviral drug at present. Treat with IFN-α aerosol inhalation
(five million U per time for adults, two times per day), and/or Lopinavir/Ritonavir oral
administration (two tablets per time, two times per day).
E. Antibiotic treatment: avoid blind and improper use of antibiotics, especially the combination
use of broad-spectrum antibiotics. Strengthen bacteriological monitoring. Antibiotics should be
used in time in secondary bacterial infection.

6.3. Treatment of Severe and Critical Cases

A. Treatment principle: based on symptomatic treatment, actively prevent and treat complications,
treat basic diseases, prevent secondary infection, and timely apply organ function support.
B. Respiratory support: apply noninvasive mechanical ventilation for two hours, if the condition
is not improved, or the patient is intolerable to noninvasive ventilation, accompanied with
increased airway secretions, severe coughing, or unstable hemodynamics, the patient should
be transferred to invasive mechanical ventilation in time. The “lung-protective ventilation
strategy” with low tidal volume should be adopted in invasive mechanical ventilation to reduce
ventilator-associated lung injury. If necessary, ventilation in the prone position, recruitment
maneuver, or extracorporeal membrane oxygenation (ECMO) can be used.
C. Circulation support: improve microcirculation based on full fluid resuscitation, use vasoactive
drugs, and apply hemodynamic monitoring if necessary.
J. Clin. Med. 2020, 9, 575 7 of 10

D. Others: according to the degree of dyspnea and the progress of chest imaging, use glucocorticoids
appropriately for a short time (3–5 days) with the recommended dose no more than what is
equivalent to methylprednisolone 1–2 mg/kg·day.

7. Prevention and Control

As of 26 January 2020, 30 provinces have initiated a level-1 public health response to control
COVID-19 [22]. A level-1 response means that during the occurrence of a particularly serious public
health emergency, the provincial headquarters shall organize and coordinate the emergency response
work within its administrative area according to the decision deployment and unified command
of the State Council [22]. Fever observation rooms shall be set up at stations, airports, ports, and
so on to detect the body temperature of passengers entering and leaving the area and implement
observation/registration for the suspicious patients. The government under its jurisdiction shall,
in accordance with the law, take compulsory measures to restrict all kinds of the congregation, and
ensure the supply of living resources. They will also ensure the sufficient supply of masks, disinfectants,
and other protective articles on the market, and standardize the market order. The strengthening of
public health surveillance, hygiene knowledge publicity, and monitoring of public places and key
groups is required. Comprehensive medical institutions and some specialized hospitals should be
prepared to accept COVID-19 patients to ensure that severe and critical cases can be differentiated,
diagnosed, and effectively treated in time. The health administration departments, public health
departments, and medical institutions at all (province, city, county, district, township, and street) levels,
and social organizations shall function in epidemic prevention and control and provide guidance for
patients and close contact families for disease prevention [23].
The responsibilities of the organizations are shown in Table 2. In accordance with the working
principle of “prevention first, prevention and control combined, scientific guidance and timely
treatment”, the prevention and control work shall be carried out in a coordinated and standardized
way [23].

Table 2. Responsibilities for the different organizations at all (province, city, county, district, township,
and street) levels in the outbreak of COVID-19.

Organization at all Levels Health Administration Center for Diseases Control Medical Institutions
Department
Objectives To timely find and report the COVID-19 cases, understand the disease characteristics and
possible sources of infection, standardize the management of close contacts, and prevent
the spread of the epidemic.
Responsibilities Overall guidance of epidemic Organization, coordination, Case detection and
control, organizing a technical supervision, and evaluation report, isolation,
expert group for prevention of the monitoring work; diagnosis, and treatment;
and control; formulation and collection, analysis, report, clinical management and
improvement of relevant work and feedback of the prevention and control of
and technical schemes, and monitoring data; nosocomial infections;
implementation of funds and epidemiological sample collection and
materials for disease investigation; strengthening detection, and training of
prevention and control; laboratory testing ability, medical staff in
tracking and management of bio-safety protection the institution.
close contacts. awareness, and technical
training; carrying out health
education and publicity and
risk communication to
the public.
J. Clin. Med. 2020, 9, 575 8 of 10

8. Discussion
The recent outbreak of the unknown severe pneumonia in China is caused by a novel coronavirus
named 2019-nCoV [2], later was designated SARS-CoV-2 by the International Committee on Taxonomy
of Viruses. This virus and the SARSr-CoV/MERSr-CoV share a common ancestor [2]. Compared
with SARSr-CoV and MERSr-CoV, SARS-CoV-2 results in much lower mortality in patients but has a
comparable infection ability. From the analysis of the fatal cases of this novel coronavirus pneumonia,
the comorbidities of hypertension, diabetes, coronary heart disease, cerebral infarction, and chronic
bronchitis were found to be dangerous factors that resulted in death.
In 2002 and 2003, the outbreak of SARS brought a disaster to the people of the world, especially
the Chinese people [24,25]. Fortunately, SARS was finally defeated, and Chinese health departments
upgraded their disease prevention and control system by summing up their experiences of fighting
SARS. Thus, when COVID-19 appeared, the whole country quickly entered a state of fighting against
the new infectious disease. Policies led by the National Health Commission have been formulated and
implemented efficiently, and Chinese scientists identified the etiology of the disease in no more than
a month. However, new cases are increasing every day, showing a trend of spreading to the whole
country and across the world.
COVID-19 appeared just one month before the Spring Festival of China, and the massive population
flow has brought great challenges for disease prevention and control. This virus can be transmitted
from human to human and no effective treatment drug has been found. The most effective prevention
and control measures are to find suspected patients and close contacts, confirm patients and virus
carriers, and block the transmission through isolation, disinfection, and personal protection. Therefore,
early detection, isolation, and treatment of patients are the key measures to control the source of
infection and reduce the infection rate. It is also crucial to avoid nosocomial infection by strengthening
the management of medical staff and patients. Health education on knowledge for disease prevention
and control is also important. Finally, if we want to eliminate the threat of this novel coronavirus
pneumonia similar to SARS, we need to learn more about the pathogenesis of the virus and develop
specific vaccines and therapeutic drugs as soon as possible.

Supplementary Materials: The following are available online at http://www.mdpi.com/2077-0383/9/2/575/s1,

Supplementary Data 1, The case information is from the reports released by official channels.
Author Contributions: Conceptualization, H.-J.P. and S.-Q.D.; methodology, H.-J.P. and S.-Q.D.; software, H.-J.P.
and S.-Q.D.; formal analysis, H.-J.P. and S.-Q.D.; investigation, H.-J.P. and S.-Q.D.; data check, H.-J.P. and S.-Q.D.;
writing—original draft preparation, H.-J.P. and S.-Q.D.; writing—review and editing, H.-J.P.; funding acquisition,
H.-J.P. All authors have read and agreed to the published version of the manuscript.
Funding: This research was funded by National Natural Science Foundation of China (81572012,
81772217, 20180907, 81971954), Guangdong Provincial Natural Science Foundation Project (2016A030311025,
2017A030313694), Science and Technology Planning Project of Guangdong Province (2018A050506038), and Key
project of Guangzhou science research (201904020011) to H.J.P.
Acknowledgments: The authors thank Zhi-Yi Zhong for her support in data analysis.
Conflicts of Interest: The authors declare no conflicts of interest.

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