half year into the pandemic: hong kong chapter
DESCRIPTION
Half year into the pandemic: Hong Kong chapter. Dr. Thomas Tsang Controller, Centre for Health Protection October 17, 2009. Where are we now?. Laboratory confirmed cases (as of October 10, 2009). Cumulative: 30,225 Dependent on testing policy. Weekly number of ILI patients attending DFCs. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/1.jpg)
Half year into the pandemic: Hong Kong chapter
Dr. Thomas TsangController, Centre for Health Protection
October 17, 2009
![Page 2: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/2.jpg)
Where are we now?
![Page 3: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/3.jpg)
Laboratory confirmed cases(as of October 10, 2009)
• Cumulative: 30,225 • Dependent on testing policy
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
. . . . . . . . . . . . . . . . . . . . . . . . . . .
5 6 7 8 9 10
2009
Severe cases (嚴重個案)
Non-severe cases (非嚴重個案)
Num
ber
of c
ases
(個案數目
)
![Page 4: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/4.jpg)
Weekly number of ILI patients attending DFCs
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 7 8 9 10 11 12
2009
No.
of I
LI c
ase
s a
tten
ded
DF
Cs
指定流感診所的流感樣求診個案數目
![Page 5: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/5.jpg)
ILI consultation rate among sentinel GPs
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 2 3 4 5 6 7 8 9 10 11 12
Month (月)
Ra
te (
pe
r 1
00
0 c
on
sulta
tion
s)比
率 (
每1
00
0 個
診 症
)
2007 2008 2009
![Page 6: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/6.jpg)
Institutional ILI outbreaks
0
50
100
150
200
250
300
350
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 2 3 4 5 6 7 8 9 1011 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10
2007 2008 2009
Nu
mbe
r of
out
bre
aks
(爆發數目
)
Influenza-like illness outbreaks (流感樣爆發個案)
![Page 7: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/7.jpg)
% +ve for HSI among tested DFC patients
0
10
20
30
40
50
60
70
80
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 7 8 9 10 11 12
2009
Per
cent
age
test
ed p
ositi
ve fo
r H
SI a
mon
g D
FC
atte
ndee
s
指定流感診所求診者對人類豬型流感測試呈陽性反應的百分比
![Page 8: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/8.jpg)
HSI: dominant strain of influenza virus
Percentage of flu virus among all flu viruses detected
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
. . . . . . . . . . . . . . . . . . . . . . . . . .
5 6 7 8 9 10
Pe
rce
nta
ge
of
flu v
iruse
s a
mo
ng
all
flu v
iruse
s d
ete
cte
d
HSI H3N2 H1N1 A (Not typed) B C
![Page 9: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/9.jpg)
Age distribution & attack rate (May 1 – Oct 10)
67% : < 20 years old82% : < 30 years old
0500
1000150020002500300035004000450050005500600065007000
0-4
5-9
10-1
4
15-1
9
20-2
4
25-2
9
30-3
4
35-3
9
40-4
4
45-4
9
50-5
4
55-5
9
60-6
4
65-6
9
70-7
4
75-7
9
80-8
4
85 o
r abo
ve
Age group 年齡組別
Num
ber o
f cas
es 個案數目
02004006008001000120014001600180020002200240026002800
Atta
ck ra
te (c
ases
/ 10
0,00
0 po
pula
tion)
發病率
()
個案每十萬人口
HSI cases
Attack rate
![Page 10: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/10.jpg)
Hospitalization and age (Jun 27 – Sep 27)
0
1000
2000
3000
4000
5000
6000
7000
8000
<=5 6 -- 11 12 -- 18 19-29 30-39 40-49 50-59 60-64 >=65
Age group 年齡組別
Num
ber o
f cas
es 個案數目
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
Perc
enta
ge re
quiri
ng h
ospi
talis
atio
n住院百分比
Admitted Not admitted Percentage requiring hospitalisation
Overall percentage of cases requiring hospitalization: 13.9%
![Page 11: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/11.jpg)
Severe & fatal HSI (as of October, 14)
• 142 severe HSI infections– 0.46% of total laboratory confirmed cases– 83 males; 59 females– Aged 13 months - 93 years (median: 51 years)– 75% had underlying diseases/risk factors– 66% required intensive care– Nucleotide sequencing closely similar to circulating HSI strain
• 32 fatal cases– 23 males; 9 females– Aged 11 years - 93 years (median: 55.5 years)– Case fatality ratio = 0.1%– 88% had underlying diseases/risk factors
![Page 12: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/12.jpg)
ILI outbreaks (Sep 1 – Oct 9)
• 1,076 ILI outbreaks
• 1,017 (94.5%) in schools– 150 (13.9%) in kindergartens / child care centres– 441 (41.0%) in primary schools– 404 (37.5%) in secondary schools– 22 (2.0%) in special schools
• 51 advised to suspend classes
![Page 13: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/13.jpg)
Antiviral resistance
• 3 sporadic cases in HK– One case associated with post-exposure prophylaxis– No onward transmission of drug-resistant viruses
• Global situation (as of Sep 27)– 28 oseltamivir-resistant HSI isolates– All show same H275Y mutation that confers
resistance to oseltamivir, but not to zanamivir– Worldwide, > 10,000 specimens of HSI virus have
been tested and found to be sensitive to oseltamivir
![Page 14: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/14.jpg)
Containment phase measures
• Case isolation
• Contact management– Quarantine– Direct Observed Chemoprophylaxis– Medical surveillance
• Border health measures
• Surveillance, hygiene campaigns, etc.
![Page 15: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/15.jpg)
Mitigation phase measures• Schools
– Early summer break for primary schools, kindergartens, etc.– Suspension of schools with large HSI outbreak
• Designated Fever Clinics
• Management of serious cases
• Antiviral stockpile deployment
• Vaccination
• Surveillance, self-care, hygiene campaigns, etc.
![Page 16: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/16.jpg)
Case fatality (as of October 4, 2009)
WHO Region
Cumulative total
Cases* Deaths
Africa 12,382 70
Americas 146,016 3,292
Eastern Mediterranean 12861 80
Europe > 59,000 > 193
South-East Asia 38,038 480
Western Pacific 109,926 410
Total > 378,223 > 4,525
1,462 deaths in 177,457 cases reported to WHO (August 13), crude case fatality rate = 0.82% (HK = 0.1%: intensive testing?)
![Page 17: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/17.jpg)
Effect of community hygienic measures on respiratory viruses isolation (2003)
• Respiratory infections during SARS outbreak, Hong Kong, 2003 (Emerg Infect Dis. 2005 Nov;11(11):1738-41)– Effect of during SARS outbreak studied by comparing proportion of
+ve specimens of various respiratory viruses in 2003 with those from 1998 to 2002
– Community hygienic measures significantly reduced incidence of respiratory viral infections
![Page 18: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/18.jpg)
Effect of school closure (2008 Easter, HK)
GOPCs (2008)*
0
3
6
9
12
15
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12
March April
Date
ILI c
ases
/ 1,
000
cons
ulta
tions
Sentinel GPs (2008)
0
10
20
30
40
50
60
70
80
90
100
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12
March April
Date
ILI
cases /
1,0
00 c
onsultations
2008
0
10
20
30
40
50
60
70
80
2 3 4 5 6 7 8 9 10 1112 1314 15 1617 1819 20 2122 2324 25 2627 2829 30 31 1 2 3 4 5 6 7 8 9 1011 12
March April
Date
Num
ber
of is
olat
es0
5
10
15
20
25
30
35
Per
cent
age
posi
tive
influenza isolates
Percentage
: school closure period
Influenza virus isolation at Public HealthLaboratory Centre
Sentinel ILI consultation rates (GOPCs/GPs)
![Page 19: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/19.jpg)
What else from here?
![Page 20: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/20.jpg)
‘In the 1918–1919 pandemic, 1st wave began in March 1918 and spread unevenly through United States, Europe, and possibly Asia over the next 6 months. Illness rates were high, but death rates in most locales were not appreciably above normal. A 2nd or fall wave spread globally from September to November 1918 and was highly fatal.’
Taubenberger JK, Morens DM. Emerg Infect Dis [serial on the Internet]. 2006 Jan [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol12no01/05-0979.htm
![Page 21: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/21.jpg)
“Asian Flu 1957”• May 1957: WHO received news of extensive influenza epidemics in
HK & Singapore
• Epidemics had begun at end of February in China
• In 6 months, every part of the world had experienced cases
• 1st wave: concentrated in school-aged children
• 2nd wave: followed disappearance of the first from 1 to 3 months later, causing very high rate of illness and increased fatalities and affected mostly elderly
• Estimated deaths > 2 millions
Avian influenza: assessing the pandemic threat. WHO. January 2005.
![Page 22: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/22.jpg)
Mortality Distributions & Timing of Waves of Previous Pandemics
Miller MA, et al. N Engl J Med. 2009 May 7.
![Page 23: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/23.jpg)
• More rapid population movement
• Higher prevalence of pre-existing medical conditions
• Medical advances, antibiotics, antivirals
What’s different in 21st century
![Page 24: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/24.jpg)
Strategies• Surveillance
• Medical services
• Non-pharmacological measures– Hygiene, outbreak management,
social distancing, etc.
• Pharmacological measures– Antivirals– Vaccines
![Page 25: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/25.jpg)
Seasonal flu & pneumococcal vaccination programs
• Government Vaccination Program
• Private doctors
– Childhood Influenza Vaccination Subsidy Scheme
– Elderly Vaccination Subsidy Scheme
![Page 26: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/26.jpg)
Vaccination subsidy schemes• Government will subsidise:
– Elderly Vaccination Subsidy Scheme - eligible elders to receive influenza vaccine & pneumococcal vaccine from private doctors
– Childhood Influenza Vaccination Subsidy Scheme - children age between 6 months and less than 6 years to receive influenza vaccine from private doctors
![Page 27: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/27.jpg)
Target groups for HSI vaccination
• Recommendations of Scientific Committees of CHP
– Healthcare workers
– Persons at higher risk of death and complications from HSI due to underlying medical conditions (including pregnancy)
– Children aged > 6 months and below 6 years old
– Elderly persons aged > 65
![Page 28: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/28.jpg)
Patients with chronic diseases have much higher percentage of serious illnesses across all age groups
CategoriesNumber of severe cases#
Percentage of cases classified as ‘severe’ (%)
Number of fatal cases
Percentage of cases died (%)
<=5 years with chronic diseases 1 7.14% 0 0%
<=5 years without chronic diseases 2 0.12% 0 0%
6-11 years (primary school students) with chronic diseases 1 1.72% 0 0%
6-11 years (primary school students) without chronic diseases 1 0.05% 0 0%
12-18 years (secondary school students) with chronic diseases 1 1.45% 0 0%
12-18 years (secondary school students) without chronic diseases 2 0.07% 0 0%
19-64 years (adults) with chronic diseases 13 3.64% 3 0.84%
19-64 years (adults) without chronic diseases 31 0.53% 7 0.12%
>=65 years (elderly) with chronic diseases 13 15.48% 2 2.38%
>=65 years (elderly) without chronic diseases 1 1.85% 0 0%
#Information on chronic disease status is available in 12,795 cases out of the 14,363 cases
![Page 29: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/29.jpg)
Elderly, young children, patients with chronic diseases have higher hospitalization rates
CategoriesTotal number of cases#
Percentage requiring hospitalization* (%)
<=5 years with chronic diseases 14 42.9%
<=5 years without chronic diseases 1,669 31.8%
6-11 years (primary school students) with chronic diseases 58 13.8%
6-11 years (primary school students) without chronic diseases 1,859 15.4%
12-18 years (secondary school students) with chronic diseases 69 24.6%
12-18 years (secondary school students) without chronic diseases 2,802 8.2%
19-64 years (adults) with chronic diseases 357 22.4%
19-64 years (adults) without chronic diseases 5,829 8.1%
>=65 years (elderly) with chronic diseases 84 60.7%
>=65 years (elderly) without chronic diseases 54 60.8%
#Information on chronic disease status is available in 12,795 cases out of the 14,363 cases*Calculation based on cases confirmed between 27 June and 7 September (in mitigation phase when only relatively serious cases require hospitalization)
![Page 30: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/30.jpg)
Most severe cases occur in adults Elders and young children have highest rates of severe illness
Age groups
Number of cases classified as ‘severe’
Percentage of cases classified as ‘severe’ (%)
Reported severe cases / 100,000 population)
Number of fatal cases
Case fatality rate (%)
Deaths / 100,000 population
< 6 years 3 0.15% 1.10 0 0% 0
6-11 years (primary school students)
2 0.08% 0.58 0 0% 0
12-18 years (secondary school students)
3 0.09% 0.51 0 0% 0
19-64 years (adults) 44 0.66% 0.90 9 0.14% 0.18
65 years (elderly) 14 9.46% 1.55 3 2.03% 0.33
![Page 31: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/31.jpg)
Young children have highest attack rates Young children and elders have highest hospitalization rates
Age groupsNumber of cases
Percentage of total cases (%)
Reported cases/100,000 population
Percentage of cases requiring hospitalization* (%)
< 6 years 1,961 13.7% 719.6 29.1%
6-11 years (primary school students)
2,359 16.4% 681.0 13.9%
12-18 years (secondary school students)
3,254 22.7% 554.6 8.0%
19-64 years (adults) 6,641 46.2% 135.5 9.0%
65 years (elderly) 148 1.0% 16.4 61.4%
![Page 32: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/32.jpg)
Pregnant women have high percentage of hospitalization
CategoriesTotal number of cases
Percentage of all cases (%)
Percentage requiring hospitalization* (%)
Persons with chronic disease# 582 4.05% 27.8%
Pregnant women 97 0.68% 71.1%
HA staff 408 2.84% 3.0%
Age < 6 year without chronic illness 1,669 11.62% 31.8%
Age 65 years old without chronic illness 54 0.38% 60.8%
#Information on chronic disease status is available in 12,795 cases out of the 14,363 cases*Calculation based on cases confirmed between 27 June and 7 September (in mitigation phase when only relatively serious cases require hospitalization)
![Page 33: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/33.jpg)
Background Incidence of GBS
Overseas Hong Kong
Background incidence (literature)
10-20 per million adults
<15 years 6 per millionOver 15 years 4.4 per million
HA data (2003-2008 Oct 15)
-
Total number during the period<15 years: 19 cases (2-7 per year)>=15 year: 279 cases (43-56 per year)
Average Incidence7.4 per million
AFP data (age<15y) -
2004: 2 cases (1.99 per million)2005: 8 cases (8.25 per million)2006: 3 cases (3.19 per million)2007: 2 cases (2.17 per million)2008: 1 case (1.11 per million)Average: 3.20 cases (3.34 per million)
After flu vaccination1-2 per million vaccinated
Not available
![Page 34: Half year into the pandemic: Hong Kong chapter](https://reader035.vdocument.in/reader035/viewer/2022062809/5681597e550346895dc6bc56/html5/thumbnails/34.jpg)
Summary
• Epidemiology of HSI in HK is in general agreement with global picture (low case fatality ratio real or artifact?)
• Recent data shows HSI probably peaked late September
• Timing and severity of ‘second wave’ uncertain
• School closures seemed to have delayed transmission, but outbreaks returned once school re-opened
• Local epidemiological data supports target groups for HSI vaccination, including persons with underlying medical conditions, young children, elders, HCW