2009 H1N1 Influenza in Minnesota
Epidemiology
Infectious Disease Epidemiology,
Prevention and Control Division
PO Box 64975
St. Paul, MN 55164-0975
Number of Hospitalized Cases of Influenza by Influenza Type,
Minnesota, October 2008 – April 2010
2009-2010 Influenza Season
September 1, 2009 – April, 2010
450
425
A/B (rapid test only)
400
B (rapid test only)
375
A (rapid test only)
Number of Hospitalizations
350
Seasonal B
325
Untypeable A (likely 2009
H1N1)
2009 H1N1
300
275
Seasonal A
250
225
200
Spring Influenza Surveillance
May 1, 2009 – August 31, 2009
175
2008-2009 Influenza Season
October 1, 2008 – April 30, 2009
150
125
100
75
1st H1N1
hospitalized case
50
25
0
40
43
46
49
52
2
5
8
11
14
17
20
23
26
29
32
35
38
41
Week of Specimen Collection
44
47
50
1
4
7
10
13
16
Number of Hospitalized PCR-confirmed 2009 H1N1
Influenza Cases, Minnesota, April 2009 – April 2010
400
Number of Hospitalizations
350
300
250
200
150
100
50
0
15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Week of Specimen Collection
1
3
Dec
5
7
Jan
9 11 13 15 17
Feb
Cumulative Incidence of Hospitalized PCR-confirmed 2009
H1N1 Influenza Cases, Minnesota, April 2009 - April 2010
Hospitalizations per 100,000 Persons
40
35
30
25
20
15
10
5
0
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
Week of Specimen Collection
52
2
4
6
8
0
12
14
16
Percentage of Outpatient Visits for ILI*, Sentinel
Surveillance Sites by Season, Minnesota,
September 2007 – April 2010
10
07-08 Season
08-09 Season
09-10 Season
% of Outpatient Visits for ILI
9
8
7
Fall Wave
2009
6
Spring Wave
Normal Flu Surveillance
October 1 – April 30
5
2009
4
3
2
1
0
35 37 39 41 43 45 47 49 51 1
*Influenza-like Illness
3
5
7
9 11 13 15 17 19 21 23 25 27 29 31 33 35
Week of Clinic Visit
Number and Percentage of Schools Reporting Outbreaks
of ILI*, Minnesota, September 2009 – April 2010
350
25%
300
Number of Schools
20%
250
Number of Schools Reporting ILI
200
15%
Percent of Eligible Schools Reporting ILI
150
10%
100
5%
50
*Influenza-like Illness
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
0%
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
0
Week of Outbreak
Number and Percentage of Culture-Confirmed
Influenza Specimens, Minnesota Virology
Laboratories, September 2007 – April 2010
100
175
Flu A/B+
150
Flu B+
Flu A+
125
2007-2008 % +
2008-2009 % +
90
80
70
60
2009-2010 % +
100
50
40
75
30
50
20
25
10
0
0
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Week of Specimen Collection
% of Positive Culture Tests
Number of Positive Culture Tests
200
Number and Percentage of Positive Influenza Rapid
Test Results, Minnesota Rapid Testing Sites,
September 2007 – April 2010
100
Flu B+
1250
1000
90
Flu A/B+
Flu A+
80
2007-2008 % +
70
2008-2009 % +
2009-2010 % +
60
750
50
40
500
30
20
250
10
0
0
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Week of Specimen Collection
% of Positive Rapid Tests
Number of Positive Rapid Tests
1500
Circulating Respiratory Viruses, Laboratory Influenza
Surveillance Program, Minnesota, October 2009 – April 2010
200
180
Number of Positives
160
140
120
Adenovirus
Enterovirus
Influenza A
Influenza B
Human Metapneumovirus
Parainfluenza – 1
Parainfluenza – 2
Parainfluenza – 3
Parainfluenza – 4
Rhinovirus
RSV
100
80
60
40
20
0
40
42
44
46
48
50
52
2
4
6
8
Week of Submission
10
12
14
16
18
Number and Incidence of Hospitalized PCRconfirmed 2009 H1N1 Influenza by Age Group,
Minnesota, April 2009 – April 2010
Number of Hospitalizations
500
120
Hospitalizations per 100,000 Persons
100
Number of Hospitalizations
400
350
80
300
250
60
200
40
150
100
20
50
0
0
0-4
5-18
19-24
25-49
Age Group (yrs.)
50-64
65+
Hospitalizations per 100,000 Persons
450
Number and Incidence of Hospitalized PCR-confirmed
2009 H1N1 Influenza Cases by Race/Ethnicity,
Minnesota, April 2009 – April 2010
Number of Cases
Incidence per 100,000
26.2
259
45
43.2
104.2
140
83
1,179
68.0
73.9
White
Black
Native American
Hispanic
Asian
Proportion of Hospitalized PCR-confirmed 2009
H1N1 Influenza Cases by Race/Ethnicity,
Minnesota, April 2009 – April 2010
Spring Wave
Multi Race
Native
American
Fall Wave
Unknown
Native
American
Multi Race
Unknown
Asian
Asian
White
Hispanic
Black
Hispanic
White
Black
Median Age of Hospitalized PCR-confirmed 2009
H1N1 Influenza Cases by Race/Ethnicity,
Minnesota, April 2009 – April 2010
Race/Ethnicity
Spring Wave
Fall Wave
White
16.9 yrs.
30.0 yrs.
Black
12.3 yrs.
20.3 yrs.
Hispanic
5.3 yrs.
8.4 yrs.
Asian
5.4 yrs.
11.7 yrs.
Native American
48.2 yrs.
36.3 yrs.
All Races
11.1 yrs.
26.8 yrs.
Incidence of Hospitalized PCR-confirmed 2009 H1N1
Influenza by Week, Minnesota, April 2009 – April 2010
“Fall Wave”
Hospitalizations per 100,000 Persons
10
9
8
7
6
5
“Spring Wave”
7-County Minneapolis-St. Paul Metro
Greater Minnesota
4
3
2
1
0
18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52
Week of Specimen Collection
Smoothed lines
2
4
6
8
10 12 14 16
Number of Hospitalized PCR-confirmed 2009 H1N1 Cases by
District of Residence, April 2009 – April 2010
Northwest
18
Northeast
129
Central
West
Central
57
Gran
t
Tod
d
280
Dougla
s
71
t
Hennepi
n
Metro 1025
Southwest 67
Southeast
South
Central
Marti
Faribaul
n
92
t
Steel
e
156
Dodg
e
Olmste
d
50
40.2
39.1
40
36.5
32.1
30
32.1
30.6
24.9
20
11.7
10
st
he
a
So
ut
es
t
hw
So
ut
So
ut
h
Ce
n
tra
l
ro
M
et
ra
l
Ce
nt
tra
l
tC
en
W
es
ea
st
No
r th
we
s
t
0
No
r th
Hospitalizations per 100,000 Persons
Incidence of Hospitalized PCR-confirmed 2009 H1N1
Influenza by District of Residence,
Minnesota, April 2009 – April 2010
Incidence of Hospitalized PCR-confirmed 2009 H1N1
Influenza by District of Residence and Wave,
Minnesota, April 2009 – April 2010
Spring
Fall
40
30
20
10
So
ut
he
as
t
So
ut
hw
es
t
l
Ce
nt
ra
So
ut
h
M
et
ro
l
Ce
nt
ra
al
en
tr
es
tC
W
No
rth
ea
st
es
t
0
No
rth
w
Hospitalizations per 100,000 Persons
50
Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases
by Age Group and Presence of Underlying Medical
Conditions, Minnesota, April 2009 – April 2010
Without Underlying Medical Condition
With Underlying Medical Condition(s)
Adult
Pediatric
0%
10%
20%
30%
40%
50%
60%
Percent of Cases
70%
80%
90%
100%
Underlying Medical Conditions of Hospitalized PCRconfirmed 2009 H1N1 Influenza Adult (≥ 18 yrs.) Cases,
Minnesota, April 2009 – April 2010
Underlying Medical Condition
Total
Percent
Asthma
328
32%
Chronic Metabolic Disease
288
28%
Chronic Lung Disease
201
20%
Chronic Cardiovascular Disease
225
22%
Immunosuppressive Condition
108
11%
Cognitive Dysfunction
54
5%
Neuromuscular Disorder
62
6%
Cystic Fibrosis
7
1%
Chronic Renal Disease
92
9%
Cancer
30
3%
Underlying Medical Conditions of Hospitalized PCRconfirmed 2009 H1N1 Influenza Pediatric (<18 yrs.) Cases,
Minnesota, April 2009 – April 2010
Underlying Medical Conditions
Total
Percent
Asthma
228
28%
Chronic Metabolic Disease
26
3%
Chronic Lung Disease
30
4%
Chronic Cardiovascular Disease
24
3%
Immunosuppressive Condition
32
4%
Developmental Delay
65
8%
Neuromuscular Disorder
37
5%
Cystic Fibrosis
2
<1%
Seizure Disorder
39
5%
Proportion of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases
Admitted to ICU by Age Group and Presence of Underlying Medical
Conditions, Minnesota, April 2009 – April 2010
50%
% of Cases Admitted to ICU
Without Underlying Medical Condition
With Underlying Medical Condition(s)
40%
30%
19% All Cases
20%
10%
0%
Pediatric
Adult
Proportion of Hospitalized PCR-confirmed 2009 H1N1
Influenza Cases Requiring Mechanical Ventilation by Age
Group and Presence of Underlying Medical Conditions,
Minnesota, April 2009 – April 2010
% of Cases Requiring Mechanical Ventilation
50%
Without Underlying Medical Condition
40%
With Underlying Medical Condition(s)
30%
20%
10% All Cases
10%
0%
Pediatric
Adult
Proportion of Hospitalized PCR-confirmed 2009 H1N1 Influenza
Cases Diagnosed with Pneumonia by Age Group and Presence of
Underlying Medical Conditions,
Minnesota, April 2009 – April 2010
Without Underlying Medical Condition
With Underlying Medical Condition(s)
% of Cases with Pneumonia
50%
37% All Cases
40%
30%
20%
10%
0%
Pediatric
Adult
% of Cases with Bacterial Co-Infection
Proportion of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases
with Bacterial Co-Infection* by Age Group and Presence of Underlying
Medical Conditions, Minnesota, April 2009 – April 2010
10%
Without Underlying Medical Condition
With Underlying Medical Condition(s)
8%
6%
4%
1.6% All Cases
2%
0%
Pediatric
Adult
*Cultural confirmation of a bacterial pathogen from sterile site within 3 days of admission.
Number and Percentage of Female Hospitalized PCRconfirmed 2009 H1N1 Influenza Cases Ages 13-49 Who
Were Pregnant, Minnesota, April 2009 – April 2010
Spring Wave
Fall Wave
Total
Females 13-49 Yrs.
n=54
n=329
n=383
Pregnant Cases
20 (37%)
46 (14%)
66 (17%)
Hospitalized PCR-confirmed 2009 H1N1
Influenza Cases in Minnesota: Summary
From April 1, 2009 to April 30, 2010: 1,824 hospitalized PCRconfirmed 2009 H1N1 Influenza cases; 1,564 since September 1,
2009
– In Spring wave:
• Median age, 11.8 years
• 17% in ICU
• 81% Cases from Metro Area
– In Fall wave:
• Median age, 26.5 years
• 20% in ICU
• 52% Cases from Metro Area
– Pregnancy among hospitalized women 13 - 49 years of age:
• 17% (of 384)
Number of Deaths Related to Influenza A,
Minnesota, April 2009 – April 2010
67 Deaths Related to Influenza A
• 63 2009 H1N1 Influenza
• 4 Influenza A, Not Subtyped
• 55 Hospitalized
• 12 Non-hospitalized
Deaths Related to Influenza A by Wave and Age Group,
Minnesota, April 2009 – April 2010
Age Group (yrs.)
Spring
Fall
Total
<18
2
6
8
18-64
1
45
46
65+
1
12
13
Total Deaths
4
63
67
Deaths Related to Influenza A by Race/Ethnicity, Minnesota,
April 2009 – April 2010
(63=2009 H1N1; 4=unspecified Influenza A)
Asian
Native American
Hispanic
Black
White
Influenza A Deaths in Minnesota by Week of Collection, (N=67)
Minnesota, April 2009 – April 2010
13
Metro
12
Northeast
Number of Deaths
11
8
Northwest
South
Central
Southeast
7
Southwest
6
Central
5
West Central
10
9
4
3
2
1
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
Jun
Jul
Aug
Sep
Oct
Week of Collection
Nov
Dec
1
2
Jan
9
Mar
Influenza A Crude Death Rates by District of Residence,
Minnesota, April 2009 – April 2010
(63=2009 H1N1; 4=unspecified Influenza A)
Deaths n=67
Crude Death Rate per
100,000 Persons
Northwest
2
1.34
Northeast
11
3.43
West Central
2
0.77
Central
7
0.99
Metro*
30
1.07
South Central
5
1.93
Southwest
2
0.91
Southeast
8
1.65
District
*All 4 deaths in spring wave occurred in Metro district residents
Deaths Related to Influenza A by Age Group and Presence
of Underlying Medical Condition(s),
Minnesota, April 2009 – April 2010
(63=2009 H1N1; 4=unspecified Influenza A)
Age Group (yrs.)
Total Deaths
% With Underlying
Medical Condition(s)
<18
8
75.0%
18-64
46
84.8%
≥65
13
92.3%
All Ages
67
87.7%
Underlying Medical Conditions among Deaths Related to
Influenza A, Minnesota, April 2009 – April 2010
(63=2009 H1N1; 4=unspecified Influenza A)
Underlying Medical Condition
Total
Percent
Obesity
30
46.9%
Chronic Cardiovascular Disease
27
42.2%
Chronic Metabolic Disease
21
32.8%
Immunosuppressive Condition
15
23.4%
Chronic Lung Disease
11
17.2%
Renal Disease
9
14.1%
Neuromuscular Disorder
7
10.9%
History of Lymphoma/Leukemia
6
9.4%
Cognitive Dysfunction
6
9.4%
Asthma
6
9.4%
Cancer Diagnosis in last 12 months
4
6.3%
Seizure Disorder
4
6.3%
Pregnant
0
0.0%
BMI of Adult Deaths Related to Influenza A, Minnesota,
April 2009 – April 2010
(55=2009 H1N1; 4=unspecified Influenza A)
5%
17%
20%
Underweight:
<18.5
Normal:
18.5–24.9
Overweight:
25.0–29.9
Obese:
30.0–39.9
Morbidly Obese:
≥40
24%
12%
22%
Unknown
Clinical Outcomes of Deaths Related to Influenza A by Age
Group, Minnesota, April 2009 – April 2010
(63=2009 H1N1; 4=unspecified Influenza A)
Pediatric <18 yrs.
n=8
Clinical Outcome
Adult 18+ yrs.
n=59
Hospitalized
5 (62.5%)
50 (84.7%)
ICU
5 (62.5%)
46 (78.0%)
Mechanical Ventilation
6 (75%)
40 (67.8%)
ARDS
1 (12.5%)
16 (27.1%)
Pneumonia
5 (62.5%)
48 (81.4%)
0
10 (16.9%)
1 (12.5%)
3 (5.5%)
0
3 (5.5%)
Viral
Bacterial
Both
Bacterial Co-Infections in Deaths Related to Influenza A,
Minnesota,
April 2009 – April 2010
(63=2009 H1N1; 4=unspecified Influenza A)
Sterile
Non-sterile*
Combined
Total (%)
Total (%)
Total (%)
Persons with Bacterial
Co-infection(s)
10 (15%)
10 (15%)
20 (30%)
Staphylococcus aureus
5 (7%)
4 (6%)
9 (13%)
MRSA
3 (4%)
2 (3%)
5 (7%)
MSSA
0
1 (1%)
1 (1%)
Unknown
2 (3%)
1 (1%)
3 (4%)
Streptococcus pneumoniae
3 (4%)
0
3 (4%)
Group B Streptococcus
2 (3%)
4 (6%)
6 (9%)
Pseudomonas aeruginosa
1 (1%)
1 (1%)
2 (3%)
Bacterial Other**
2 (3%)
7 (10%)
9 (13%)
*Non-sterile sites include sputum, endotracheal aspirate, lung tissue, and stool
**Stenotrophomonas maltophilia, Enterobacter cloacae, Staphylococcus saprophyticus,
Staphylococcus coagulase negative, Enterococcal sepsis, Moraxella catarrhalis, Group A
Streptococcus, Escherichia coli, VRE
Summary of Deaths Related to Influenza A,
Minnesota, April 2009 – April 2010
In Spring wave
• 4 deaths (all PCR-confirmed 2009 H1N1)
• 2 in children; 1 in an adult age 65 or older
• 1 with no underlying conditions
• 100% 7-county MSP area
In Fall wave
• 63 deaths (59 2009 H1N1, 4 Influenza A-type
unspecified)
• 6 in children; 12 > 65 y
• 7 no underlying conditions
• 41% (26/63) 7-county MSP area
For More Information Please Contact:
Minnesota Department of Health
Acute Disease Investigation and Control
651-201-5414
1-877-676-5414
www.health.state.mn.us