Influenza A (H1N1)pdm09 in Minnesota
Epidemiology
Infectious Disease Epidemiology,
Prevention and Control Division
PO Box 64975
St. Paul, MN 55164-0975
Number of Influenza Hospitalizations by Influenza Type,
Minnesota, October 2008 – April 2010
2009-2010 Influenza Season
September 1, 2009 – April,
2010
450
A/B (rapid test only)
B (rapid test only)
A (rapid test only)
Seasonal B
Untypeable A [likely A (H1N1)pdm09]
A (H1N1)pdm09
Seasonal A
425
400
375
Number of Hospitalizations
350
325
300
275
250
225
200
175
Spring Influenza
Surveillance
May 1, 2009 – August 31,
2009
2008-2009 Influenza Season
October 1, 2008 – April 30,
2009
150
125
100
75
1st A (H1N1)pdm09
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 A (H1N1) pdm09 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 1
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
3
Dec
Week of Specimen Collection
5
7
Jan
9 11 13 15 17
Feb
Cumulative Incidence of Hospitalized PCR-confirmed A (H1N1) pdm09
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* among Sentinel
Surveillance Sites, by Season,
Minnesota, September 2007 – April 2010
% of Outpatient Visits for ILI
10
07-08 Season
08-09 Season
09-10 Season
9
8
7
6
Fall Wave
2009
5
Normal influenza
Surveillance
October 1 – April 30
4
Spring Wave
2009
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
25%
350
300
Number of Schools Reporting ILI
Number of Schools
Percent of Eligible Schools Reporting ILI
20%
250
15%
200
150
10%
100
5%
50
0%
0
*Influenza-like Illness
Week of Outbreak
Number and Percentage of Culture-Confirmed Influenza
Specimens, Minnesota Virology Laboratories
September 2007 – April 2010
200
100
Number of Positive Culture Tests
Flu B+
Flu A+
150
2009-2010 % +
2008-2009 % +
125
2007-2008 % +
90
80
70
60
100
50
75
40
30
50
20
25
0
10
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
Flu A/B+
175
Number and Percentage of Positive Influenza Rapid Test Results,
Minnesota Rapid Testing Sites, September 2007 – April 2010
Number of Positive Rapid Tests
1250
Flu B+
90
Flu A/B+
80
Flu A+
2009-2010 % +
1000
2008-2009 % +
2007-2008 % +
750
70
60
50
40
500
30
20
250
10
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
0
% of Positive Rapid Tests
100
1500
Circulating Respiratory Viruses, Laboratory Influenza Surveillance Program,
Minnesota, October 2009 – April 2010
200
Adenovirus
Influenza A
Human Metapneumovirus
Parainfluenza – 2
Parainfluenza – 4
RSV
180
Number of Positives
160
140
Enterovirus
Influenza B
Parainfluenza – 1
Parainfluenza – 3
Rhinovirus
120
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 PCR-confirmed A (H1N1)
pdm09 Cases by Age Group, Minnesota, April 2009 – April 2010
Number of Hospitalizations
500
120
Hospitalizations per 100,000 Persons
450
Number of Hospitalizations
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
100
400
Number and Incidence of Hospitalized PCR-confirmed A (H1N1) pdm09
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 A (H1N1) pdm09
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 A (H1N1) pdm09
Cases by Race/Ethnicity, Minnesota, April 2009 – April 2010
Race/Ethnicity
Spring Wave
White
16.9 yrs.
30.0 yrs.
5.4 yrs.
11.7 yrs.
Black
12.3 yrs.
Native American
48.2 yrs.
Hispanic
Asian
All Races
5.3 yrs.
11.1 yrs.
Fall Wave
20.3 yrs.
8.4 yrs.
36.3 yrs.
26.8 yrs.
Incidence of Hospitalized PCR-confirmed A (H1N1) pdm09 Cases
by Week, Minnesota, April 2009 – April 2010
Fall Wave
Hospitalizations per 100,000 Persons
10
9
7-County Minneapolis-St. Paul Metro
8
Greater Minnesota
7
6
5
Spring Wave
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
2
4
6
8
10 12 14 16
Number of Hospitalized PCR-confirmed A (H1N1) pdm09 Cases by
District of Residence, April 2009 – April 2010
Northwest
18
Northeast
129
West
Central
57
Central
Tod
d
280
Douglas
Grant
71
t
Metro 1025
Hennepi
n
Southwest 67
Southeast
South
Central
Marti
Faribaul
n
92
t
Steele
156
Dodge
Olmste
d
Hospitalizations per 100,000 Persons
Incidence of Hospitalized PCR-confirmed A (H1N1)pdm09 Cases
by District of Residence, Minnesota, April 2009 – April 2010
50
40.2
40
39.1
36.5
32.1
30
24.9
20
11.7
10
0
30.6
32.1
Incidence of Hospitalized PCR-confirmed A (H1N1)pdm09 Cases by
District of Residence and Wave, Minnesota, April 2009 – April 2010
Hospitalizations per 100,000 Persons
50
40
30
20
10
0
Spring
Fall
Hospitalized PCR-confirmed A (H1N1)pdm09 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 PCR-confirmed A (H1N1)
pdm09 Adult (≥ 18 yrs.) Cases, Minnesota, April 2009 – April 2010
Underlying Medical Condition
Total
Percent
Asthma
328
32%
Chronic Cardiovascular Disease
201
225
20%
Chronic Metabolic Disease
Chronic Lung Disease
Immunosuppressive Condition
Cognitive Dysfunction
Neuromuscular Disorder
Cystic Fibrosis
Chronic Renal Disease
Cancer
288
108
54
62
28%
22%
11%
5%
6%
7
1%
30
3%
92
9%
Underlying Medical Conditions of Hospitalized PCR-confirmed A (H1N1)
pdm09 Pediatric (<18 yrs.) Cases, Minnesota, April 2009 – April 2010
Underlying Medical Conditions
Total
Percent
Asthma
228
28%
Chronic Cardiovascular Disease
24
3%
Chronic Metabolic Disease
Chronic Lung Disease
Immunosuppressive Condition
Developmental Delay
Neuromuscular Disorder
Cystic Fibrosis
Seizure Disorder
26
30
32
65
37
2
39
3%
4%
4%
8%
5%
<1%
5%
Proportion of Hospitalized PCR-confirmed A (H1N1)pdm09 Cases
Admitted to the 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 A (H1N1)pdm09
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
With Underlying Medical Condition(s)
45%
40%
35%
30%
25%
20%
15%
10% All Cases
10%
5%
0%
Pediatric
Adult
Proportion of Hospitalized PCR-confirmed A (H1N1) pdm09 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%
40%
37% All Cases
30%
20%
10%
0%
Pediatric
Adult
% of Cases with Bacterial Co-Infection
Proportion of Hospitalized PCR-confirmed A (H1N1) pdm09 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 Hospitalized PCR-confirmed A (H1N1) pdm09
Cases Ages 13-49 Who Were Pregnant
Minnesota, April 2009 – April 2010
Spring Wave
Females 13-49 Yrs.
Pregnant Cases
n=54
20 (37%)
Fall Wave
n=329
46 (14%)
Total
n=383
66 (17%)
Hospitalized PCR-confirmed A (H1N1) pdm09 Cases in Minnesota:
Summary
From April 1, 2009 to April 30, 2010: 1,824 hospitalized PCR-confirmed
2009 H1N1 Influenza cases; 1,564 since September 1, 2009
• In Spring wave:
• Median age: 11.8 years
• 17% admitted to the ICU
• 81% cases from Minneapolis-St. Paul metropolitan area
• In Fall wave:
• Median age: 26.5 years
• 20% admitted to the ICU
• 52% cases from Minneapolis-St. Paul metropolitan 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 (H1N1) pdm09, 4 Influenza A, Not
Subtyped
• 55 Hospitalized
• 12 Not hospitalized
Number of Deaths Related to Influenza A by Wave and Age Group,
Minnesota, April 2009 – April 2010
Age Group (yrs.)
<18
18-64
65+
Total Deaths
Spring
Fall
2
1
1
4
Total
6
45
12
63
8
46
13
67
Deaths Related to Influenza A by Race/Ethnicity,
Minnesota, April 2009 – April 2010
[63=(H1N1)pdm09; 4=unspecified Influenza A]
Hispanic
Black
Asian
Native
American
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
Northwest
10
South Central
9
8
Southeast
7
Southwest
6
Central
5
West Central
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
Jun
Jul
Aug
Sep
Oct
Week of Collection
Nov
51 52
Dec
1
2
Jan
9
Mar
Influenza A Crude Death Rates by District of Residence,
Minnesota, April 2009 – April 2010
[63=(H1N1)pdm09; 4=unspecified Influenza A)
District
Northwest
Northeast
West Central
Central
Metro*
South Central
Southwest
Southeast
Deaths n=67
Crude Death Rate per 100,000
Persons
2
1.34
11
3.43
2
0.77
30
1.07
7
0.99
5
1.93
8
1.65
2
*All 4 deaths in spring wave occurred in Metro district residents
0.91
Deaths Related to Influenza A by Age Group and Presence of Underlying
Medical Condition(s), Minnesota, April 2009 – April 2010
[63=(H1N1)pdm09; 4=unspecified Influenza A]
Age Group (yrs.)
Deaths
% With Underlying Medical
Condition(s)
<18
8
75.0%
67
87.7%
18-64
≥65
All Ages
46
13
84.8%
92.3%
Underlying Medical Conditions among Deaths Related to
Influenza A, Minnesota, April 2009 – April 2010
[63=(H1N1)pdm09; 4=unspecified Influenza A]
Underlying Medical Condition
Obesity
Chronic Cardiovascular Disease
Chronic Metabolic Disease
Immunosuppressive Condition
Chronic Lung Disease
Renal Disease
Neuromuscular Disorder
History of Lymphoma/Leukemia
Cognitive Dysfunction
Asthma
Cancer Diagnosis in last 12 months
Seizure Disorder
Pregnant
Total
Percent
30
46.9%
21
32.8%
27
15
11
9
7
6
6
6
4
4
0
42.2%
23.4%
17.2%
14.1%
10.9%
9.4%
9.4%
9.4%
6.3%
6.3%
0.0%
Body Mass Index of Adult Deaths Related to Influenza A,
Minnesota, April 2009 – April 2010
17%
[55=(H1N1)pdm09; 4=unspecified Influenza A]
5%
20%
24%
12%
22%
Underweight: <18.5
Normal: 18.5–24.9
Overweight: 25.0–29.9
Obese: 30.0–39.9
Morbidly Obese: ≥40
Unknown
Clinical Outcomes of Deaths Related to Influenza A by Age Group,
Minnesota, April 2009 – April 2010
[63=(H1N1)pdm09; 4=unspecified Influenza A)
Pediatric <18 yrs.
n=8
Clinical Outcome
Hospitalized
Intensive Care Unit Admission
Mechanical Ventilation
Acute Respiratory Distress
Syndrome (ARDS)
Pneumonia
Viral
Bacterial
Both
Adult 18+ yrs.
n=59
5 (62.5%)
50 (84.7%)
6 (75%)
40 (67.8%)
5 (62.5%)
1 (12.5%)
5 (62.5%)
0
1 (12.5%)
0
46 (78.0%)
16 (27.1%)
48 (81.4%)
10 (16.9%)
3 (5.5%)
3 (5.5%)
Bacterial Co-Infections in Deaths Related to Influenza A, Minnesota,
April 2009 – April 2010
[63=(H1N1)pdm09; 4=unspecified Influenza A)
Persons with Bacterial
Co-infection(s)
Staphylococcus aureus
MRSA
MSSA
Unknown
Streptococcus pneumoniae
Group B Streptococcus
Pseudomonas aeruginosa
Bacterial Other**
Sterile
Non-sterile*
Combined
Total (%)
Total (%)
Total (%)
10 (15%)
10 (15%)
20 (30%)
5 (7%)
4 (6%)
9 (13%)
0
1 (1%)
1 (1%)
3 (4%)
2 (3%)
3 (4%)
2 (3%)
1 (1%)
2 (3%)
2 (3%)
1 (1%)
0
4 (6%)
1 (1%)
7 (10%)
5 (7%)
3 (4%)
3 (4%)
6 (9%)
2 (3%)
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
Spring wave
• 4 deaths [all PCR-confirmed A (H1N1)pdm09]
• 2 children; 1 adult (age 65 or older)
• 1 with no underlying conditions
• 100% Minneapolis-St. Paul metropolitan area
Fall wave
• 63 deaths [59 A (H1N1)pdm09, 4 Influenza A-type
unspecified]
• 6 children; 12 adults (age 65 or older)
• 7 with no underlying conditions
• 41% Minneapolis-St. Paul metropolitan 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