2009 H1N1 Influenza in Minnesota Epidemiology

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

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A/B (rapid test only)

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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

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

April 2010

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ILI

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

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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

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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

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

April 2010

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Adenovirus Enterovirus

Influenza A Influenza B

Human Metapneumovirus Parainfluenza – 1

Parainfluenza – 2 Parainfluenza – 3

Parainfluenza – 4 Rhinovirus

RSV

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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,

Minnesota, April 2009 –

April 2010

Number of Cases Incidence per 100,000

White Black AsianHispanicNative American

43.2

73.9

68.0

26.2

104.2

1,179

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83

140

259

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Black

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Hispanic

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American

Spring Wave Fall Wave

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

Minnesota, April 2009 –

April 2010

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

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7-County Minneapolis-St. Paul MetroGreater Minnesota

Smoothed lines

“Spring Wave”

“Fall Wave”

Marti

nFaribaul

t

Olmste

dDodg

eSteel

e

Hennepi

n

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Tod

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Dougla

sGran

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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

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

Minnesota, April 2009 –

April 2010

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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,

Minnesota, April 2009 –

April 2010

Underlying Medical Condition Total PercentAsthma 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,

Minnesota, April 2009 –

April 2010

Underlying Medical Conditions Total PercentAsthma 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

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Pediatric Adult

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dmitt

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ICU

Without Underlying Medical Condition

With Underlying Medical Condition(s)

19% All Cases

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Pediatric Adult

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With Underlying Medical Condition(s)

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

10% All Cases

0%

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Pediatric Adult

% o

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ith P

neum

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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

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Pediatric Adult

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acte

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o-In

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Without Underlying Medical Condition

With Underlying Medical Condition(s)

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 TotalFemales 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

Num

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f Dea

ths

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

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Central

Southwest

Southeast

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MarJan

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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

(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)

17%

24%

5%

20%

12%

22%

Underweight:<18.5Normal:18.5–24.9Overweight:25.0–29.9Obese:30.0–39.9Morbidly Obese:≥40Unknown

Clinical Outcomes of Deaths Related to Influenza

A by Age Group, Minnesota, April 2009 –

April 2010

(63=2009 H1N1; 4=unspecified Influenza A)

Clinical OutcomePediatric <18 yrs.

n=8Adult 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

651-201-54141-877-676-5414

www.health.state.mn.us