Download SARS与H1N1的流行概况

SARS与H1N1的流行概况
余运贤
流行病学与卫生统计学教研组
1
传染病和流行病学的概念

传染病是由病原体（细菌、病毒和寄生虫）
引起的能在人与人或人与动物之间传播的
疾病。

流行病学是研究人群中疾病与健康状况的
分布及其影响因素，并研究防制疾病及促
进健康的策略和措施的科学。
2
传染病流行的基本环节

传染源 ：散播病原体的人或动物

传播途径：病原体离开传染源到达健
康人所经过的途径

易感人群：对某种传染病缺乏免疫力
而容易感染该病的人群
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传染病的预防措施：
1、控制传染源
2、切断传播途径
3、保护易感人群
4
描述性研究（descriptive study）
通过描述疾病或健康状况的三间分布情况，找出某些因素
与疾病或健康状况间的关系，提供病因线索。
又称描述性流行病学。指根据日常记录资料或通过特殊调
查所得的资料，包括实验室检查结果。按不同地区、不同
时间及不同人群特征分组，将一个社区人群疾病或健康状
态分布情况进行简单描述，常常是流行病学调查的第一步，
也是分析流行病学的基础。它主要描述分布的三大特征，
即：地区特征、时间特征和人群特征。
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Severe Acute Respiratory Syndrome
(SARS）




The 2002-2003 SARS outbreak infected 8,422
individuals leading to 916 deaths in eight affected areas
The first case was identified on 16 November 2002 in
the southern Chinese city of Foshan.
The epidemic then spread within Guangdong province
before a large superspreading event in Hong Kong
seeded the global outbreak.
On 5 July 2003, the World Health Organization (WHO)
announced the last affected area Taiwan to be
transmission free and declared the last human-tohuman transmission chain successfully interrupted
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SARS 传染源


SARS coronavirus (CoV), was identified as the
infectious agent in the syndrome.
The origin of this pandemic remains unclear.
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SARS Epidemiology
The first wave
 a chef from Heyuan who worked at a restaurant in
Shenzhen was reported to have atypical pneumonia；
 His wife, two sisters, and seven medical staff were
infected；
 SARS was outbreak in Heyuen in early Dec, 2002;
 The outbreak happened in Zhongshan. 28 case were
recognised. 13 of the 28 patients were health-care
workers.
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SARS Epidemiology
The second wave —since Jan 12, 2003

A 46-year-old male seafood merchant who was admitted to the Second Affiliated
Hospital of Zhongshan University on Jan 31, 2003.

The patient stayed in the hospital for only 18 h, but caused more than 30 hospital
staff to become infected.

During transfer, ambulance driver, two doctors, and two nurses were infected.

Within the next 8 days, 20 more medical staff and 19 family members who had
been in contact with the patient became infected.

And then resulted in outbreak in Guangzhou.

In mid-February, one doctor working at the Second Affiliated Hospital of
Zhongshan travelled to Hong Kong, and became the major source of the SARS
The outbreak was characterised by infection within hospitals and family clusters,
suggesting that transmission arises through close contact with infected patients.
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Characteristics of SARS patients in Hong Kong,
Beijing and Taiwan.
Hong Kong (n=1755)
Characteristic
No. of
patients (%)
CFR
*
(%)
Beijing (n=917)
No. of
†
AOR (95% CI)
patients
(%)
CFR
(%)
Taiwan (n=664)
No. of
AOR (95% CI)
patients
(%)
CFR
(%)
‡
AOR (95% CI)
Sex
Female
978 (56)
13.2
Male
777 (44)
515 (29)
1
405 (44)
3.0
1
22.3 1.40 (1.01-1.94)
512 (56)
3.5 0.85 (0.38-1.87)
0.6 0.05 (0.01-0.18)
440 (48)
0.2
341 (52)
22.6
1
311 (48)
33.1 1.17 (0.79-1.74)
170 (26)
13.5 0.74 (0.39-1.42)
101 (15)
10.9 0.55 (0.25-1.22)
121 (19)
19.8
Age group (years)
0-30
7.1 0.68 (0.38-1.20)
1.0
151 (17)
2.6
‡
31-40
379 (22)
41-50
320 (18)
11.6
51-60
170 (10)
17.6 1.46 (0.83-2.60)
76 (8.3)
11.8 7.72 (2.37-25.2)
78 (12)
42.3 2.59 (1.33-5.04)
60+
371 (21)
55.3 5.63 (3.52-9.01)
57 (6.2)
24.6 8.52 (2.36-30.8)
181 (28)
48.6 2.94 (1.66-5.21)
455 (70)
22.2
197 (30)
40.1 1.64 (1.09-2.46)
598 (92)
23.9
1
193 (21)
‡
n/a
n/a
1
1
Preexisting comorbid conditions
No
1395 (80)
Yes
358 (20)
10.0
1
45.5 1.59 (1.09-2.31)
755 (96)
35 (4.4)
1.5
1
14.3 4.06 (1.62-10.19)
1
Admitted before symptom onset
No
Yes
1636 (93)
119 (6.8)
14.6
1
52.9 1.45 (0.88-2.38)
859 (94)
3.5
58 (6.3)
0.0
1
§
n/a
50 (7.7)
1
70.0 4.85 (2.46-9.53)
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Lau et al. BMC Infectious Diseases 2010, 10:50
Figure 2A shows the epidemic curve
in each region
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12
SARS Incubation


The estimated means of the incubation
distributions were 4.4 days in Hong Kong, 5.7
days in Beijing and 6.9 in Taiwan.
The mean delay from onset to admission were
3.6, 2.7 and 2.8 days respectively for Hong Kong,
Beijing and Taiwan.
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传播途径






water-borne
Food-borne
blood-borne
vector-borne
Air-borne
others
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SARS病毒的传播
主要经过紧密接触传
播，以近距离飞沫传播
为主，也可通过手接触
呼吸道分泌物，经口鼻
眼传播，另有研究发现
存在粪-口传播的可能。
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危险人群：
1、医务人员
2、家庭成员、共同生活者
3、关系密切的朋友
4、接触病人者
密切接触
16
Nanshan Zhong.
BMJ
2006;333;389391
17
H1N1 Epidemic






WHO declared a pandemic in June 2009, a total of 74 countries
and territories had reported laboratory confirmed infections.
As of October 2009, worldwide H1N1 virus has been implicated
in over 318 925 laboratory-confirmed human cases and 3917
deaths.
As of 20 May 2009, 10 243 laboratory-confirmed cases of new
influenza A (H1N1) virus infection, including 80 deaths, had
been reported to WHO from 41 countries.
Most of these cases were from North America (USA, 5469;
Mexico, 3734; Canada, 496).
The majority of fatal cases were reported from Mexico
Approximately 2–5% of confirmed cases in the United States
and Canada, as well as 6% in Mexico, have been admitted to
hospital.
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H1N1 distribution by age
http://www.who.int/wer
19
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High risk for hospitalization



Almost one-half of the patients hospitalized in the United States,
and 21 of 45 (46%) fatal cases in Mexico have had underlying
conditions, including pregnancy, asthma, other lung diseases,
diabetes, morbid obesity, autoimmune disorders and associated
immunosuppressive therapies, neurological disorders and
cardiovascular disease.
Among 20 pregnant women in the United States confirmed to
have been infected with new influenza A (H1N1) virus, 3
required hospitalization, 1 of whom died.
Among 30 patients hospitalized in California, 64% had
underlying conditions and 2 of 5 pregnant women developed
complications, including spontaneous abortion and premature
rupture of membranes.
http://www.who.int/wer
21
Map: International Co-circulation of 2009 H1N1 and Seasonal Influenza
(As of October 2, 2009; posted October 2, 2009, 11:00 AM ET)
22
HINI Incubation

The median incubation period of the virus was
2 days (range, 1 to 7).
Cao et al. N Engl J Med 2009;361:2507-17.
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甲型流感病毒
•
•
•
•
病毒家族:正黏液病毒科
基因组为单股负链RNA病毒
呈球形，直径8O一120 nm，有囊膜
根据外膜蛋白血凝素抗原(HA)和神经氨酸酶
(NA)，甲型流感病毒可以分为l5个H亚型
感谢: L. Stammard, 1995
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传播途径

The pandemic H1N1 virus is spread from
person to person, similar to seasonal influenza
viruses. It is transmitted as easily as the normal
seasonal flu and can be passed to other people
by exposure to infected droplets expelled by
coughing or sneezing that can be inhaled, or that
can contaminate hands or surfaces.
25
Population
Immunization
in 2008
Miller et al. Lancet. 2010 Mar 27;375(9720):1100-8.
26
Baseline immunization in 2008
Miller et al. Lancet. 2010 Mar 27;375(9720):1100-8.
27
The population immunization in
2009
Miller et al. Lancet. 2010 Mar 27;375(9720):1100-8.
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Special example for influenza

when an airplane that held 54 passengers, 1 of
whom had influenza, was grounded for three
hours with a failed air-circulation system, a
clinical syndrome of influenza developed in 72
percent of all passengers during the next three
days.
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Daniel M. Musher
N Engl J Med
2003;348:1256-66.
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How to protect from H1N1




Avoidance of infections that are spread by large droplets
requires avoidance of close contact with ill persons.
In the case of infections that are spread by droplet nuclei,
shared space should also be avoided unless ventilation is
extremely good: attending a Broadway show during an
outbreak of influenza is certainly not advisable for a
person who has not been vaccinated.
Washing hands after greeting someone with a viral
infection may be appropriate, because viruses may be
transmitted by direct contact,
and self-inoculation is an important part of pathogenesis.
31
流感疫苗研究现状
6月8日，甲
型H1N1流
感疫苗生产
用毒株，从
美国运抵北
京，标志着
甲型H1N1
流感疫苗的
批量生产正
式启动。
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Controlling communicable diseases (1)

Preparedness and prevention
training health and outreach staff
 supplies and equipment for diagnosis, treatment and
environmental health measures;
 strengthening health surveillance systems and practicing
protocols for managing information on certain diseases;
 raising awareness among the population

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Health care worker infected in SARS
outbreak



From November 2002 to July 2003, severe respiratory
distress syndrome (SARS) quickly spread from Foshan
(Shunde district), Guangdong Province in the People’s
Republic of China to 33 other countries or regions on 5
continents.
There were 8447 cases, 21% occurring in health care
workers (HCWs), and 813 deaths (9.6% overall
mortality) by the time of July 2003.
In the Hong Kong and Hanoi outbreaks, 46% and
63% of cases occurred in HCWs, respectively.
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Controlling communicable diseases (2)

Public-health surveillance


Public-health surveillance is the collection, analysis and dissemination
of health information to enable appropriate action to be taken.
Outbreak control


Suspected disease outbreaks, indicated by information from a health
surveillance system, should be rapidly investigated using standards
protocols for assessment
The two main strategies for controlling outbreaks of communicable
disease are to reduce the number of cases through preventive
activities and to reduce mortality due to the disease through early case
detection and effective treatment
35
Outbreak control

Preventive and curative measures work together
to reduce the sources of infection by rapidly
isolating and treating patients and controlling animal
reservoirs;
 to protect susceptible groups through immunization,
nutritional support and possibly chemoprophylaxis
 to reduce transmission through improvements in
hygiene conditions and hygiene behaviour.

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医院是传染病管理的前哨



医院是传染病的集散地
医务人员是传染病的高暴露人群
医务人员要承担传染病管理的任务
传染病报告
 病人管理
 疾病监测

37
Thanks！！！
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