2009 H1N1 Influenza in Minnesota Epidemiology

2009 H1N1 Influenza in Minnesota Epidemiology

Infectious Disease Epidemiology, Prevention and Control DivisionPO Box 64975St. Paul, MN 55164-0975

0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

40 43 46 49 52 2 5 8 11 14 17 20 23 26 29 32 35 38 41 44 47 50 1 4 7 10 13 16

Week of Specimen Collection

Nu

mb

er o

f H

osp

ital

izat

ion

s

A/B (rapid test only)

B (rapid test only)

A (rapid test only)

Seasonal B

Untypeable A (likely 2009H1N1)2009 H1N1

Seasonal A

2008-2009 Influenza SeasonOctober 1, 2008 – April 30, 2009

2009-2010 Influenza SeasonSeptember 1, 2009 – April, 2010

Spring Influenza SurveillanceMay 1, 2009 – August 31, 2009

1st H1N1hospitalized case

Number of Hospitalized Cases of Influenza by Influenza Type,

Minnesota, October 2008 – April 2010

Number of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases, Minnesota, April 2009 – April 2010

0

50

100

150

200

250

300

350

400

15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 1 3 5 7 9 11 13 15 17


Nu

mb

er

of

Ho

sp

ita

liza

tio

ns

Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb

0

5

10

15

20

25

30

35

40

18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 2 4 6 8 0 12 14 16


Ho

sp

ita

liza

tio

ns

pe

r 1

00

,00

0 P

ers

on

sCumulative Incidence of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases, Minnesota, April 2009 - April 2010

0

1

2

3

4

5

6

7

8

9

10

35 37 39 41 43 45 47 49 51 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35

Week of Clinic Visit

% o

f O

utpa

tien

t V

isit

s fo

r IL

I

07-08 Season 08-09 Season 09-10 Season

Percentage of Outpatient Visits for ILI*, Sentinel Surveillance Sites by Season, Minnesota,

September 2007 – April 2010

*Influenza-like Illness

Spring Wave

2009

Fall Wave

2009

Normal Flu Surveillance October 1 – April 30

Number and Percentage of Schools Reporting Outbreaks of ILI*, Minnesota, September 2009 – April 2010

0

50

100

150

200

250

300

350

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 Outbreak

Nu

mb

er

of

Sc

ho

ols

0%

5%

10%

15%

20%

25%

Number of Schools Reporting ILI

Percent of Eligible Schools Reporting ILI

*Influenza-like Illness

Number and Percentage of Culture-Confirmed Influenza Specimens, Minnesota Virology

Laboratories, September 2007 – April 2010

0

25

50

75

100

125

150

175

200

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


Nu

mb

er o

f P

osi

tive

Cu

ltu

re T

ests

0

10

20

30

40

50

60

70

80

90

100

% o

f P

os

itiv

e C

ult

ure

Te

sts

Flu A/B+

Flu B+

Flu A+

2007-2008 % +

2008-2009 % +

2009-2010 % +

Number and Percentage of Positive Influenza Rapid Test Results, Minnesota Rapid Testing Sites,

September 2007 – April 2010

0

250

500

750

1000

1250

1500

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


Nu

mb

er

of

Po

sit

ive

Ra

pid

Te

sts

0

10

20

30

40

50

60

70

80

90

100

% o

f P

os

itiv

e R

ap

id T

es

ts

Flu B+

Flu A/B+

Flu A+

2007-2008 % +

2008-2009 % +

2009-2010 % +

Circulating Respiratory Viruses, Laboratory Influenza Surveillance Program, Minnesota, October 2009 – April 2010

0

20

40

60

80

100

120

140

160

180

200

40 42 44 46 48 50 52 2 4 6 8 10 12 14 16 18

Week of Submission

Nu

mb

er

of

Po

sit

ive

s

Adenovirus Enterovirus

Influenza A Influenza B

Human Metapneumovirus Parainfluenza – 1

Parainfluenza – 2 Parainfluenza – 3

Parainfluenza – 4 Rhinovirus

RSV

0

50

100

150

200

250

300

350

400

450

500

0-4 5-18 19-24 25-49 50-64 65+

Age Group (yrs.)

Nu

mb

er

of

Ho

sp

ita

liza

tio

ns

0

20

40

60

80

100

120

Ho

sp

ita

liza

tio

ns

pe

r 1

00

,00

0 P

ers

on

s

Number of Hospitalizations

Hospitalizations per 100,000 Persons

Number and Incidence of Hospitalized PCR-confirmed 2009 H1N1 Influenza by Age Group,

Minnesota, April 2009 – April 2010

Number and Incidence of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases by Race/Ethnicity,


Number of Cases Incidence per 100,000

White Black AsianHispanicNative American

43.2

73.9

68.0

26.2

104.2

1,179

45

83

140

259

White

Black

Hispanic

Unknown

Asian

Native American

Multi Race

White

Black

Hispanic

Asian

UnknownMulti Race

Native American

Spring Wave Fall Wave

Proportion of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases by Race/Ethnicity,


Median Age of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases by Race/Ethnicity,


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

0

1

2

3

4

5

6

7

8

9

10

18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 2 4 6 8 10 12 14 16


Ho

sp

ita

liza

tio

ns

pe

r 1

00

,00

0 P

ers

on

s

7-County Minneapolis-St. Paul Metro

Greater Minnesota

Smoothed lines

“Spring Wave”

“Fall Wave”

Martin

Faribault

Olmsted

Dodge

Steele

Hennepin

t

Todd

DouglasGran

t

71

Northwest18

West Central

57

Southeast156South

Central92

Central 280

Southwest 67

Northeast 129

Metro 1025

Number of Hospitalized PCR-confirmed 2009 H1N1 Cases by District of Residence, April 2009 – April 2010

Incidence of Hospitalized PCR-confirmed 2009 H1N1 Influenza by District of Residence,Minnesota, April 2009 – April 2010

11.7

40.2

24.9

39.136.5

32.1 30.6 32.1

0

10

20

30

40

50

Ho

spita

lizat

ion

s p

er 1

00,0

00 P

erso

ns

Incidence of Hospitalized PCR-confirmed 2009 H1N1 Influenza by District of Residence and Wave,


0

10

20

30

40

50

Northw

est

Northeas

t

West

Cen

tral

Central

Metro

South C

entral

Southwest

Southeas

t

Ho

spit

aliz

atio

ns

per

100

,000

Per

son

s

SpringFall

Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases by Age Group and Presence of Underlying Medical

Conditions, Minnesota, April 2009 – April 2010

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Pediatric

Adult

Percent of Cases

Without Underlying Medical Condition

With Underlying Medical Condition(s)

Underlying Medical Conditions of Hospitalized PCR-confirmed 2009 H1N1 Influenza Adult (≥ 18 yrs.) Cases,


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 PCR-confirmed 2009 H1N1 Influenza Pediatric (<18 yrs.) Cases,


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

0%

10%

20%

30%

40%

50%

Pediatric Adult

% o

f C

as

es

Ad

mit

ted

to

ICU



19% All Cases

0%

10%

20%

30%

40%

50%

Pediatric Adult

% o

f C

ases

Req

uir

ing

Mec

han

ical

Ven

tila

tio

n Without Underlying Medical Condition


Proportion of Hospitalized PCR-confirmed 2009 H1N1 Influenza Cases Requiring Mechanical Ventilation by Age Group and Presence of Underlying Medical Conditions,


10% All Cases

0%

10%

20%

30%

40%

50%

Pediatric Adult

% o

f C

ases

wit

h P

neu

mo

nia

Without Underlying Medical Condition With Underlying Medical Condition(s)

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

37% All Cases

0%

2%

4%

6%

8%

10%

Pediatric Adult

% o

f C

as

es

wit

h B

ac

teri

al C

o-I

nfe

cti

on



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

1.6% All Cases

*Cultural confirmation of a bacterial pathogen from sterile site within 3 days of admission.

Number and Percentage of Female Hospitalized PCR-confirmed 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 PCR-confirmed 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)

Native American

Black

Hispanic

Asian

White

Influenza A Deaths in Minnesota by Week of Collection, (N=67)Minnesota, April 2009 – April 2010

South Central

Northwest

Northeast

Metro

Week of Collection

Nu

mb

er o

f D

eath

s

24 2523 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

Jun Jul Aug Sep Oct DecNov

1

2

3

4

5

6

48 49 50

7

8

9

10

11

12

West Central

Central

Southwest

Southeast

51 52 1 9

MarJan

13

2

Influenza A Crude Death Rates by District of Residence, Minnesota, April 2009 – April 2010 (63=2009 H1N1; 4=unspecified Influenza A)

District Deaths n=67Crude 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

*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


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


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


17%

24%

5%

20%

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


Clinical OutcomePediatric <18 yrs.

n=8

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%)

Viral 0 10 (16.9%)

Bacterial 1 (12.5%) 3 (5.5%)

Both 0 3 (5.5%)

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

Documents

2009 H1N1 Influenza in Minnesota Epidemiology