September 24, 2015Vickie Horan, SD Department of Health

Influenza Surveillance CoordinatorVickie.horan@state.sd.us

605-773-3737

1

Human Influenza: What is it?What is influenza ?• Contagious respiratory illness caused by influenza viruses that

infect the nose, throat, and lungs. It can cause mild to severe illness, and at times can lead to death.

Signs and symptoms of influenza:• Fever* or feeling feverish/chills.• Cough.• Sore throat.• Runny or stuffy nose.• Muscle or body aches.• Headaches.• Fatigue.• Some (especially children) have vomiting and diarrhea.

2

Influenza: How bad is it?

Uncomplicated influenza: • Abrupt onset after an incubation of 1-2 days.• Duration of symptoms: typically 3 days, but may last 4-

8 days.

Pneumonia complications of influenza:• Primary influenza viral pneumonia:

– Risk factors: pregnancy, cardiovascular disease, young adult.– Relentless progression from classic 3-day influenza.

• Secondary bacterial pneumonia: – Risk factors: age >65 years, pulmonary disease.– Bacteriology: Pneumococcus, Staphylococcus, Haemophilus.

3

Influenza and pneumonia deaths, South Dakota 2002-2013 (J09-J18)

239223

180

242

173189 186

135

166178

188 186

0

50

100

150

200

250

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Calendar year4

Human Influenza A virus subtypes circulating 1918 to present

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020

H3N2

H1N1(s)H1N1(

09)

H2N2

H1N1(A0)

H5N1

H7N9

• Antigenic Drift: minor changes occurring frequently.• Antigenic Shift: radical changes occurring at unpredictable intervals.

1957

19181968

1977

2009

5

Mandell, Douglas and Bennett. 2015. Principles and practice of infectious diseases 8th ed. P. 2004.

Other Influenza Viruses of Public Health Concern

• Human Influenza B virus:

– B strains drift but do not shift

– Victoria and Yamagata lineages currently circulating

• Swine influenza virus:

– A(H3N2) variant (Brookings County, SD 2008).

– A(H1N1) variant (Iowa Case Hospitalized in SF, SD, 2015)

• Avian influenza viruses:

– A(H5N1) emerged in Hong Kong in 1997, ongoing

– A(H7N9) emerged in China in 2013, ongoing

6

SD Influenza Surveillance: When? Where? What?

• Influenza surveillance conducted year round

• Enhanced surveillance October – May

– ILI Net

– Weekly aggregate Influenza Rapid Antigen reporting

– Laboratory confirmed influenza (PCR, culture, DFA)

– All Influenza-associated deaths

– All Influenza-associated hospitalizations

– School Illness Absentee Reporting

– Outbreak reporting (schools, day-care, long term

care facilities).

7

Confirmed, Hospitalizations & Deaths 2004-2015

8

Season Dominate virus Deaths Hospitalizations

Confirmed

cases

(Culture,PCR,

DFA) Peak week

2004-2005 A(H3N2) 42 Not reportable 684

February 3rd

week

2005-2006 A(H3N2) 11 Not reportable 636 March 2nd

week

2006-2007 A(H1N1) 6 132 400

February 3rd

week

2007-2008 A(H3N2) 22 361 684

February 4th

week

2008-2009 A(H1N1) 4 134 525 March 1st

week

2009-2010

A(H1N1)

pandemic 24 431 2,303

October 2nd

week

2010-2011 A(H3N2) 20 290 860

February 3rd

week

2011-2012 A(H3N2) 17 164 505 March 3rd

week

2012-2013 A(H3N2) 38 365 993

January 2nd

week

2013-2014

A(H1N1) 14 239 659 January 1st

week

2014-2015 A(H3N2) 63 793 1,703

January 1st

week

Influenza: ILI, confirmed cases, hospitalizations, school absenteeism and %+ rapid tests,

South Dakota 2014-2015

9

0%

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14%

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Influenza A Untyped

Influenza AH1

Influenza AH3

Influenza B

% RA Positive

% School illnessabsenteeism

Influenza cases, hospitalizations, and deaths by age group, South Dakota 2014-2015

584

509

55244

108

3

315

80

2

317

28242

68

0%

10%

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40%

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90%

100%

Confirmed cases Hospitalizations Deaths

0-4 years

5-18 years

19-49 years

50-64 years

>64 years

10

1702 793 63

Confirmed influenza cases, South Dakota 6 seasons 2009-2015

0102030405060708090

100110120130140150160170180190

40 42 44 46 48 50 52 1 3 5 7 9 11 13 15 17 19

Co

nfi

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ase

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MMWR weeks (First week October 2014 to second week May 2015)

2009-2010

2010-2011

2011-2012

2012-2013

2013-2014

2014-2015

11

Antivirals

• There are 3 Antiviral medications approved for prevention and treatment of Influenza A & B in the United States (dosing is based on age, underlying health conditions, and weight of patient):– Oseltamivir (Tamiflu): Used for treatment any age or

chemoprophylaxis >3 months.– Zanamivir (Relenza): Used for treatment >7 years or

chemoprophylaxis > 5 years. – Peramivir (Rapivab): Approved for use in U.S. Dec

2014 IV med used for treatment >18 years…not recommended for chemoprophylaxis.

12

Why use Antiviralshttp://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm

• Early treatment can shorten duration of symptoms and may reduce complications of influenza.

• Early treatment of hospitalized patients can reduce death

• Clinical benefit is greatest when antiviral treatment is administered early, especially within 48 hours of influenza illness onset.

• Influenza hospitalized patients antiviral treatment is warranted even if hospitalized after 48 hours of illness onset.

• Decisions about starting antiviral treatment should not wait for laboratory confirmation of influenza.

13

State Influenza vaccination percent coverage for 2014–2015 season (NIS and BRFSS estimates)

30

35

40

45

50

55

60

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14

South Dakota rates and rank among states by age group, (NIS/BRFSS influenza vaccination), 2014-2015

59.6%

74.3%

64.4% 63.2%59.5% 58.1%

52.3% 53.8%

59.6%56.5%

74.9%

0%

10%

20%

30%

40%

50%

60%

70%

80%

≥6 m 6m-4 yr 6m-17yr

5-12 yr 13-17 yr 18+ yr 18-49 yr 18-64 yr HR 18-64 yr

50-64 yr 65+ yr

1st13th 12th 22nd 3rd1st1st 1st 2nd

2nd 3rd

What can we expect this upcoming influenza season?

16

Global Influenza Surveillance and Response System (GISRS)

as of 17 Sep 2015

17

Current influenza in Southern hemisphere (as of 7Sep15)

• South Africa: peak 27 June, influenza activity decreased, with influenza type B predominating in recent weeks.

• South America temperate zone: peak 22 Aug, ILI and SARI activity remained low and continued to decrease in general.

• Australia: peak 30 Aug, influenza activity increasing with predominantly B virus followed by A(H3N2) detections.

18www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/

Best Prevention?

1. Get Vaccinated 2. All persons aged 6 months and

older should be vaccinated annually, with rare exception

3. When to Vaccinate?

19

Influenza peaks, South Dakota, 1999-2015Flu Season: peak week• 1999-2000: December 4th week.

• 2000-2001: February 2nd week.

• 2001-2002: March 2nd week.

• 2002-2003: March 1st week.

• 2003-2004: December 2nd week.

• 2004-2005: February 3rd week.

• 2005-2006: March 2nd week.

• 2006-2007: February 3rd week.

• 2007-2008: February 4th week.

• 2008-2009: March 1st week.

• 2009-2010: October 2nd week.

• 2010-2011: February 3rd week.

• 2011-2012: March 2nd week.

• 2012-2013: January 2nd week.

• 2013-2014: January 1st week.

• 2014-2015: January 1st week. 20

Oct7%

Dec17%

Jan21%

Feb29%

Mar29%

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Oct

2

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4

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Dec

1

Dec

2

Dec

3

Dec

4

Jan

1

Jan

2

Jan

3

Jan

4

Feb

1

Feb

2

Feb

3

Feb

4

Mar

1

Mar

2

Mar

3

Mar

4

Weeks of influenza seasons

Influenza vaccination 2015-2016 season

• Trivalent influenza vaccines will contain: – A/California/7/2009 (H1N1)-like virus– A/Switzerland/9715293/2013 (H3N2)-like virus New**– B/Phuket/3073/2013-like (Yamagata lineage) virus. New**

(same lineage as B Massachusetts as we saw in SD last season)

• Quadrivalent influenza vaccines will also contain: – B/Brisbane/60/2008-like (Victoria lineage) virus (which is the

same Victoria lineage virus recommended for quadrivalent formulations in 2013–14 and 2014–15). We did see this virus in SD last season as well.

Currently, 6 influenza vaccine manufacturers are projecting that as many as 171-179 million doses of influenza vaccine will be available for use in the United States during the 2015-2016 influenza season..

www.cdc.gov/mmwr/preview/mmwrhtml/mm6430a3.htm21

Questions???

22