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Outbreak of 2009 Pandemic Influenza A (H1N1) Virus on a University Campus – Delaware, April-May 2009 A. Danielle Iuliano, PhD MPH Division of HIV/AIDS.

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Presentation on theme: "Outbreak of 2009 Pandemic Influenza A (H1N1) Virus on a University Campus – Delaware, April-May 2009 A. Danielle Iuliano, PhD MPH Division of HIV/AIDS."— Presentation transcript:

1 Outbreak of 2009 Pandemic Influenza A (H1N1) Virus on a University Campus – Delaware, April-May 2009 A. Danielle Iuliano, PhD MPH Division of HIV/AIDS Prevention May 27, 2010

2 Outline Background Description of the Outbreak Epi-Aid objectives Studies Conclusions Recommendations

3 Influenza RNA virus – Common types A and B – Affects 5-20% of the U.S. population – 200,000 hospitalizations – 36,000 deaths Virus spread: person-to-person via respiratory droplet Prevention – Seasonal influenza vaccine – Post-exposure prophylaxis – Non-pharmaceutical interventions

4 Spectrum of Influenza Illness Several case definitions for surveillance Duration of Illness – 4 – 7 days – Some symptoms may linger Symptoms – Fever (≥ 100º F) – Feverish (chills/sweats) – Sore throat – Runny nose/nasal congestion – Cough – Shortness of breath – Abdominal Pain – Diarrhea – Nausea/vomiting – Headache – Muscle/joint aches – Ear pain/pressure – Fatigue

5 2009 Pandemic Influenza A (H1N1) Swine-origin influenza virus April 15, 2009 – First identified human infection

6 H1N1 Diagnosis Reverse transcriptase polymerase chain reaction (RT-PCR) – Used to subtype influenza viruses – H1N1 initially unsubtypeable at state labs – Early samples sent to CDC for confirmation Rapid influenza test – Can determine influenza type (A or B)

7 H1N1 Treatment Treatment – Oseltamivir (Tamiflu®) – Zanamivir (Relenza®) Most effective within 48 hours of onset

8 University of Delaware (UD) Campus: Newark University Population – 18,872 students – 5,871 faculty/staff University health clinic – Located on campus – Open 24 hrs/day, 7 days/week

9 The Outbreak April 27 University clinic saw rapid increase in student visits 4 samples sent to state for subtyping

10 The Outbreak April 27April 28 4 probable H1N1 cases identified Campus wide H1N1 alert issued University clinic saw rapid increase in student visits 4 samples sent to state for subtyping

11 The Outbreak April 27April 28April 29 Overflow clinic opened University cancels social/academic events Epi-AID Requested 4 probable H1N1 cases identified Campus wide H1N1 alert issued University clinic saw rapid increase in student visits 4 samples sent to state for subtyping

12 The Outbreak April 27April 28April 29April 30 4 H1N1 cases confirmed by CDC Athletic events canceled thru weekend CDC arrives Overflow clinic opened University cancels social/academic events Epi-AID Requested University clinic saw rapid increase in student visits 4 samples sent to state for subtyping 4 probable H1N1 cases identified Campus wide H1N1 alert issued

13 Headlines

14 At the time of this investigation H1N1 unknown characteristics – Severity of illness – Attack rate – Age distribution of illness – Effectiveness of seasonal influenza vaccine – Risk factors for transmission – Use of community mitigation measures

15 Epi-Aid Investigation Objectives Examine increase in clinic visits at the UD health clinic Describe the epidemiology of H1N1 in the university community Identify risk factors for transmission on campus

16 Studies Conducted Review of health clinic visit data Clinical chart abstraction Online H1N1 survey Qualitative study: focus groups and individual case interviews

17 Health Clinic Data

18 Review of Health Clinic Data Objectives – Describe the number of respiratory illness visits (ICD-9) – Compare visits: 2008 and 2009

19 Respiratory Illness Defined by diagnostic code (ICD-9): – Upper and/or lower respiratory infection – Influenza – Otitis media – Respiratory failure – Respiratory distress – Asthma/chronic obstructive pulmonary disease – Fever – Pneumonia – Pharyngitis – Laryngitis – Sore throat – Nasal congestion or rhinorrhea – Cough

20 Student Health Clinic Respiratory Visits, March 22 – May 9, 2009 April 29 Spring Break

21 UD Health Clinic Visits (2008 vs. 2009) Number of Visits April 27 – May 3, 2008 April 26 – May 2, 2009 All Visits9601,430 Overflow Clinic--300 Visits for Respiratory Illness3251,080 Rapid Influenza Tests--92 Oseltamivir distributed--> 500 Increase in respiratory illness visits: – More than four times the number of respiratory visits compared with 2008.

22 Online H1N1 Survey

23 Objectives – Estimate attack rates – Examine health seeking behaviors – Measure risk factors for ILI

24 Survey Methods Cross sectional survey Conducted May 10 to May 18, 2009 Online survey: University emailed link to entire university population Included questions on: – Illness and symptoms since March 27, 2009 – Health seeking behaviors – Risk factors for transmission – Community mitigation measures – Messages about H1N1

25 Analytic Methods Demographic characteristics provided by UD Respiratory illness definitions – Acute respiratory illness (ARI) Reported fever, cough, sore throat or nasal congestion/rhinorrhea Between March 27 – May 9, 2009 – Influenza-like illness (ILI) Fever plus cough or sore throat

26 Survey Response Students N=18,872 n (%) Faculty/Staff N=5,871 n (%) Respondents6049 (32%)1401 (24%) Gender Men Women 2050 (34%) 3999 (66%) 518 (37%) 883 (63%) AgeMedian (IQR) 21 (18-23)

27 Survey Response Students N=18,872 n (%) Faculty/Staff N=5,871 n (%) Respondents6049 (32%)1401 (24%) Gender Men Women 2050 (34%) 3999 (66%) 518 (37%) 883 (63%) Age 20-29 30-39 40-49 50-59 > 60 Median (IQR) 21 (18-23)66 (5%) 232 (17%) 334 (24%) 488 (39%) 281 (20%)

28 Attack Rates for ILI Students N=6049 Faculty/Staff N=1401 Acute respiratory illness (ARI)1545 (26%)194 (14%) Influenza-like illness (ILI) 604 (10%) 73 ( 5%)

29 Attack Rates for ILI Risk Factor Total ILI N (%) RR 95% CIP-value Age 18-19 20-29 30-39 40-49 50-59 > 60 1609 3941 534 479 576 311 168 (10) 412 (11) 31 (6) 19 (4) 34 (6) 12 (4) referent 1.0 (0.8-1.2) 0.6 (0.4-0.8) 0.4 (0.2-0.6) 0.5 (0.4-0.8) 0.3 (0.2-0.6) 0.99 0.003 <0.001 0.002 RR=Relative Risk, 95% CI=95% Confidence Interval

30 Attack Rates for ILI Risk Factor Total ILI N (%) RR 95% CIP-value Age 18-19 20-29 30-39 40-49 50-59 > 60 1609 3941 534 479 576 311 168 (10) 412 (11) 31 (6) 19 (4) 34 (6) 12 (4) referent 1.0 (0.8-1.2) 0.6 (0.4-0.8) 0.4 (0.2-0.6) 0.5 (0.4-0.8) 0.3 (0.2-0.6) 0.99 0.003 <0.001 0.002 RR=Relative Risk, 95% CI=95% Confidence Interval

31 Attack Rates for ILI Risk FactorTotal ILI N (%) RR 95% CIP-value Seasonal Influenza Vaccine Yes No 1931 5196 173 (9) 461 (9) 1.0 (0.8-1.2) referent0.91 RR=Relative Risk, 95% CI=95% Confidence Interval

32 ILI Characteristics and Healthcare (N=677) n (%) Median duration of illness (IQR)6 (4-9) Missed Work/Class403 (60) Median days missed (IQR)2 (1-3) Visited a healthcare provider395 (58) Stayed overnight in hospital4 (<1)

33 Onset of Reported ILI, Students (n=604) Campus wide alert issued Overflow Clinic Opens Peak in reported illness Date Cases

34 Student Risk Factors for ILI RR=Relative Risk, 95% CI=95% Confidence Interval Risk Factor Total ILI N (%) RR 95% CI P- value Housing On Campus Off Campus 2410 3639 261 (11) 343 (9) 1.2 (1.0-1.4) referent 0.08 Travel to Mexico Yes No 95 5954 22 (23) 582 (10) 2.4 (1.6-3.4) referent <0.001 ‘Greek’ Society Member Yes No 770 5258 129 (17) 475 (9) 2.0 (1.6-2.5) referent <0.001 ‘Greek Week’ Participation Yes No 589 5402 107 (18) 491 (9) 2.2 (1.8-2.8) referent <0.001

35 Student Risk Factors for ILI RR=Relative Risk, 95% CI=95% Confidence Interval Risk Factor Total ILI N (%) RR 95% CI P- value Housing On Campus Off Campus 2410 3639 261 (11) 343 (9) 1.2 (1.0-1.4) referent0.08 Travel to Mexico Yes No 95 5954 22 (23) 582 (10) 2.4 (1.6-3.4) referent<0.001 ‘Greek’ Society Member Yes No 770 5258 129 (17) 475 (9) 2.0 (1.6-2.5) referent<0.001 ‘Greek Week’ Participation Yes No 589 5402 107 (18) 491 (9) 2.2 (1.8-2.8) referent<0.001

36 Onset of Reported ILI, Students (n=604) Peak in reported illness Spring Break Travel to Mexico Cases Date

37 Onset of Reported ILI, Students (n=604) Peak in reported illness Spring Break Travel to Mexico Cases Date 13 of 20 travelers became sick during trip or within 7 days of returning

38 Student Risk Factors for ILI Risk Factor Total ILI N (%) RR 95% CI P- value Housing On Campus Off Campus 2410 3639 261 (11) 343 (9) 1.2 (1.0-1.4) referent0.08 Travel to Mexico Yes No 95 5954 22 (23) 582 (10) 2.4 (1.6-3.4) referent<0.001 ‘Greek’ Society Member Yes No 770 5258 129 (17) 475 (9) 2.0 (1.6-2.5) referent<0.001 ‘Greek Week’ Participation Yes No 589 5402 107 (18) 491 (9) 2.2 (1.8-2.8) referent<0.001 RR=Relative Risk, 95% CI=95% Confidence Interval

39 Onset of Reported ILI, Students (n=604) Spring Break ‘Greek Week’ Peak in reported illness Cases Date

40 ILI Rate by ‘Greek Week’ Participation ‘Greek Week’ Rate per 1000 people per day Date

41 Limitations H1N1 confirmatory testing for small subset – Unknown how many positive for H1N1 Low response rate to online survey Self-reported responses Generalizability – May not be representative of university population – May be different than non-participants

42 Conclusions Large outbreak of respiratory infections on UD campus in April and May 2009 Outbreak overwhelmed health system Attack rate: two times higher for students compared with faculty/staff No deaths were reported

43 Conclusions Risk of ILI decreased in older age groups No difference in the risk of ILI by seasonal influenza vaccine Risk factors for transmission – Travel to Mexico – ‘Greek Week’ participation

44 Investigation helped to answer H1N1 unknown characteristics – Severity of illness – Attack rate – Age distribution of illness – Effectiveness of seasonal influenza vaccine – Risk factors for transmission – Use of community mitigation measures

45 University of Delaware: AR: 10% CFR: 0% 1918 pandemic AR: 30% CFR: 2 % 1968 pandemic AR: 37% CFR: 0.2 % Population18,872 ILI1,8875,6626,882 Healthcare visits1,132 Hospitalizations11 Deaths011314 Severity of Illness, Delaware, 2009 AR: Attack Rate, CFR: Case Fatality Rate

46 Recommendations Provide information to the university community – Signs/symptoms – How virus spreads – Prevention methods – Who should seek care – When to seek care Distribute through multiple media sources Provide regular updates

47 Recommendations Prepare for surge in individuals seeking care – Developed in conjunction with local health authorities – Plan for additional clinic location and staff – Call center CDC guidance for universities – http://www.cdc.gov/h1n1flu/institutions/guidance/

48 Acknowledgments University of Delaware – Sharon Bathon – Steve Grasson – Richard Sacher – Joseph Siebold – Sheryl Whitlock – Marcia Nichol Delaware Health and Social Services – Paul Silverman – Paula Eggers – Leroy Hathcock – Ashley Love – Rick Hong – Karyl Rattay – Sue Shore – Crystal Webb CDC – Dave Swerdlow – Carrie Reed – Alice Guh – Deborah Dee – Tarissa Mitchell – Greg Armstrong – Kathy Byrd – Mitesh Desai – Hannah Gould – Preeta Kutty – Roni Werman – Gavin Grant – Mark Lamias – Lyn Finelli – Victor Babalban – Harvey Lipman – Mehran Massoudi – Dan Fishbein – Micah Milton – Carolyn Bridges – Michael Lynch – Mark Sotir – Joan Brunkard – Phil Ricks

49 Thank you!

50 Extra Slides

51 University Challenges Health system overwhelmed – Unexpected and rapid increase in visits Decision to cancel or not cancel classes – Students may leave campus – Community spread of the virus – Classes not canceled

52 H1N1 Case Definitions Probable case: – Positive influenza A, but unsubtypeable on RT-PCR at state laboratories Confirmed case: – Positive for H1N1 on RT-PCR at CDC

53 Clinic Visit Data

54 Student Health Service Visits, March 27 – May 9 2008 & 2009

55 Student Health Services Visits For Respiratory Illness, 2008-2009

56 Onset of Illness, Confirmed Cases (n=24)

57 Chart Abstraction

58 Clinical Chart Abstraction

59 Objectives – Describe the spectrum of illness in students seeking medical care Who were the students presenting? Were they worried ill or worried well? Did they likely have H1N1? – Examine severity of H1N1 – Compare confirmed H1N1 cases to Afebrile respiratory illness (Non ILI) Seasonal influenza A

60 Clinical Chart Abstraction Reviewed electronic medical charts From April 5 – May 8, 2009: – All confirmed Influenza A (H1N1) – Random sample of other respiratory illness Afebrile (25% sample abstracted) Febrile (50% sample abstracted) – Influenza-like illness (ILI) From February – March, 2009 – Seasonal influenza A Fever + cough or sore throat

61 Flow Chart for Selection of Charts Student Health Clinic With Fever n = 492 Without Fever n = 610 241 abstracted 132 abstracted *Data for 6 patients from external sources (CCHS, State DPH interviews) 4/5/2009–5/8/2009 Respiratory Illness n = 1102 2/1/2009–3/21/2009 Seasonal Influenza A n = 44 ILI: n = 237 Confirmed H1N1: n = 24*

62 Confirmed H1N1 vs. ILI Clinical Characteristics and Outcome Confirmed N=24 (%) ILI N=213 (%) P-value Symptoms Cough Sore throat Nasal congestion / rhinorrhea Gastrointestinal symptoms nausea, vomiting, diarrhea Myalgia Headache Fatigue 24 (100) 15 (63) 19 (79) 8 (33) 14 (58) 15 (63) 12 (50) 158 (74) 174 (82) 142 (67) 36 (17) 98 (46) 90 (42) 91 (43) 0.002 0.03 0.21 0.05 0.25 0.06 0.50 Underlying Medical Conditions Asthma 1 (4)32 (15)0.22* Hospitalizations / Deaths0 (0) - * Fisher’s Exact Test

63 Confirmed H1N1 vs. Afebrile Illness Clinical Characteristics and Outcome Confirmed N=24 (%) Afebrile N=136 (%) P-value Symptoms Cough Sore throat Nasal congestion / rhinorrhea Gastrointestinal symptoms nausea, vomiting, diarrhea Myalgia Headache Fatigue 24 (100) 15 (63) 19 (79) 8 (33) 14 (58) 15 (63) 12 (50) 83 (61) 103 (76) 89 (65) 7 (5) 18 (13) 39 (29) 21 (15) <0.001 0.17 0.19 <0.001 0.001 <0.001 Underlying Medical Conditions Asthma 1 (4)25 (18)0.13* Hospitalizations / Deaths0 (0) - * Fisher’s Exact Test

64 Clinical Characteristics and Outcome Confirmed N=24 (%) Seasonal N=44 (%) P-value Symptoms Fever Cough Sore throat Nasal congestion / rhinorrhea Gastrointestinal symptoms nausea, vomiting, diarrhea Myalgia Headache Fatigue 24 (100) 15 (63) 19 (79) 8 (33) 14 (58) 15 (63) 12 (50) 42 (95) 40 (91) 33 (75) 38 (86) 9 (20) 34 (77) 28 (64) 22 (50) 0.55 0.28 0.50 0.24 0.10 0.93 0.99 Underlying Medical Conditions Asthma 1 (4) 9 (20) 0.09* Hospitalizations / Deaths0 (0) - Confirmed H1N1 vs. Seasonal Influenza A * Fisher’s Exact Test

65 Clinical Chart Abstraction Reviewed patient medical charts: – Confirmed Influenza A (H1N1) – Acute febrile respiratory illness (AFRI) Fever (100°F or feverishness or chills) plus Cough, sore throat, nasal congestion, or rhinorrhea ILI: fever plus cough or sore throat – Other upper respiratory infection (URI) – Seasonal influenza A, February/March 2009

66 Flow Chart for Selection of Charts Student Health Clinic Febrile n = 492 Afebrile n = 610 241 abstracted 132 abstracted *Data for 6 patients from external sources (CCHS, State DPH interviews) Respiratory Illness 4/5/2009–5/8/2009 n = 1102 2/1/2009–3/21/2009 Seasonal Influenza A n = 44 ILI n = 213 Confirmed H1N1 n = 24*

67 Summary Individuals seeking care – Worried ill – Presented with spectrum of illnesses – Many same symptoms reported Possible H1N1 Severity of H1N1 illness – Mostly mild – Similar clinical illnesses between H1N1 and seasonal influenza although the numbers were small

68 Survey Data

69 Methods – Examined demographic characteristics – Calculated attack rates for ILI – Identified factors associated with transmission among students – Examined community mitigation measures

70 Survey Response Students – 6,049 (26%) participants Faculty/Staff – 1,401 (24%) participants

71 Student Symptoms Reported Symptoms ILI (n=604) N (%) Other respiratory illness (n=941) N (%) Fever Sore Throat Cough Runny Nose/Nasal Congestion Headache Nausea/Vomiting Diarrhea Shortness of Breath Muscle Aches Fatigue 604 (100) 509 (84) 475 (79) 508 (84) 426 (71) 118 (20) 131 (22) 204 (30) 361 (60) 470 (78) 61 (6.5) 625 (66) 609 (65) 771 (82) 402 (43) 80 (9) 99 (11) 171 (16) 169 (18) 397 (42)

72 Attack Rates for ILI Risk Factor Total ILI N (%) RR 95% CIP-value Underlying Health Condition* Yes No 1995 5455 193 (10) 484 (9) 1.1 (0.9-1.3) referent 0.29 Asthma Yes No 1195 6255 133 (11) 544 (9) 1.3 (1.1-1.6) referent 0.007 RR=Relative Risk, 95% CI=95% Confidence Interval * Underlying health conditions include: Asthma, chronic lung disease, chronic heart or circulatory disease (including diabetes); kidney disease, recent cancer, immunosuppressive condition, neurologic/neuromuscular disorder

73 Attack Rates for ILI Risk Factor Total ILI N (%) RR 95% CIP-value Underlying Health Condition* Yes No 1995 5455 193 (10) 484 (9) 1.1 (0.9-1.3) referent 0.29 Asthma Yes No 1195 6255 133 (11) 544 (9) 1.3 (1.1-1.6) referent0.007 RR=Relative Risk, 95% CI=95% Confidence Interval * Underlying health conditions include: Asthma, chronic lung disease, chronic heart or circulatory disease (including diabetes); kidney disease, recent cancer, immunosuppressive condition, neurologic/neuromuscular disorder

74 Health Seeking Behaviors P < 0.0001

75 Health Seeking Behaviors

76

77 Self-Protective Measures: All Students 43% concerned about catching H1N1 65% did something to protect themselves from catching H1N1 Most common self-protective measures – Increased hand washing (96%) – Avoided sick people (69%) – Did not share drinks/utensils (58%)

78 H1N1 Survey Summary: Students and Faculty/Staff Illness on campus widespread – Student attack rate higher than faculty/staff – Older age associated with decreased risk of ILI No protective effect of seasonal influenza vaccine H1N1 media coverage and fear influenced decision to seek care

79 H1N1 Survey Summary: Students Risk factors for transmission – ILI risk increased with travel to Mexico Associated with early transmission – ILI risk increased with ‘Greek Week’ participation Likely to be associated with peak in illness

80 Measures Taken: Students with Respiratory Illness Respiratory illness – Cough, sore throat, nasal congestion – With or without other symptoms – Since May 1, 2009 To assess behaviors following recommendations provided by UD

81 Measures Taken: Students with Respiratory Illness Increased personal hygiene measures – 75% increased hand washing – 68% covered cough/sneeze – 51% did not share drinks/utensils – 11% wore face mask Disregard for isolation measures – 95% left household during 7 days after illness onset – 77% attended class – 39% attended social events

82 Qualitative study

83 Confirmed Case Interview Findings Followed recommendations to prevent transmission – Practiced social isolation – Washed hands often – Some reported wearing masks Compliant with antiviral medication Many attributed disease spread on campus to ‘Greek Week’ activities or travel to Mexico

84 H1N1 Prevention H1N1 Vaccine Wash hands often with soap and water or alcohol-based hand rub Avoid touching eyes, nose or mouth Avoid close contact with sick people

85 Conclusions Risk factors for transmission – Travel to Mexico – ‘Greek Week’ participation Community Mitigation Efforts – All student participants used some protective measures to prevent illness – Students with acute respiratory illness Practiced good hygiene measures Did not follow isolation recommendations

86 Recommendations Prepare for surge in individuals seeking care – Truly ill and worried well – Use gymnasiums or other large open venues as emergency clinic space Set up an call center Consider cancelling large social events In the event of another outbreak – Provide information early with clear, easily accessible and concise – Provide rationale behind university decisions Increase student awareness about university health system

87 CDC Recommendations Experiencing ILI – Facilitate self-isolation of residential students – Promote self-isolation of non-resident students, faculty and staff – Discourage attendance at campus events General recommendations – Increase hand washing – Cover cough or sneeze – Seasonal influenza vaccine – Seek medical advice if experience illness – Complete routine cleaning of high touch areas http://www.cdc.gov/h1n1flu/institutions/guidance/

88 http://www.udel.edu/healthalert/ IT recommends technology options for course continuity in event of H1N1 outbreak

89


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