seasonal flu a basic refresher · jessica hamilton, mph epidemiologist email: jhamilton@ccchd.com...

J E S S I C A H A M I L T O N , M P H E P I D E M I O L O G I S T

E M A I L : J H A M I LT O N @ C C C H D. C O M O F F I C E : ( 9 3 7 ) 3 9 0 - 5 6 0 0 , E X T. 2 6 7

FA X : ( 9 3 7 ) 3 9 0 - 5 6 2 5

SEASONAL FLU: A BASIC REFRESHER

TYPES

• 4 types of influenza viruses: A, B, C, and D.

• Types A and B cause seasonal epidemics

• Type C are mild

• Type D primarily affect cattle

INFLUENZA A

• Further subtyped based on two proteins

residing on the surface of the virus:

• Hemagglutinin

• Neuraminidase

• H#N#

• 18 Hemagglutinin subtypes

• 11 Neuraminidase subtypes

INFLUENZA B

• Further divided by lineages and strains

• Current lineages:

• B/Yamagata

• B/Victoria

HOW FLU CHANGES

• Antigenic drift (Types A and B)

• Small changes. Typically small enough that our

immune system can still detect it with similar

antibody responses

• Constantly occurring

• Antigenic shift (only Type A)

• Big changes. When a new H and/or N

combination emerges from an animal population

and our bodies aren’t equipped to handle this.

• Occasionally occurring (H1N1 2009)

SPREADING THE FLU

• Transmits via Person-to-Person contact

• Droplets

• Up to 6 feet

• People are typically infectious beginning 1

day prior to presenting symptoms

• Remain infectious up to 5-7 days after

becoming ill

OHIO FLU UPDATE

OHIO DEPARTMENT OF HEALTH SEASONAL INFLUENZA ACTIVITY SUMMARY MMWR WEEK 12

MARCH 19TH – MARCH 25TH, 2017

• Current Ohio Activity Level – Widespread

• Definition: Increased influenza-like illness (ILI) in at least half

of the regions AND recent (within the past 3 weeks) lab

confirmed influenza in the state.

• There were 713 influenza-associated hospitalizations (IAH) reported during MMWR Week 12.

• The West Central Ohio region (includes Clark) has the lowest

# of IAHs compared to other Ohio regions

OHIO INFLUENZA ACTIVITY SUMMARY DASHBOARD

• ILI Outpatient Data

• Later and higher peak

• Longer flu season?

• Confirmed IAH

• Higher amounts overall

• Later onset

• Most recent week: Week 12 (3/25/2017)

• Baseline Averages: Week 40 (10/9/2016) – Week 20

(5/21/2017)

CDC STATE LEVEL

Ohio is classified

as Widespread

for flu, along

with our

neighboring

states

M A Y B E H E A D E D F O R A N O T H E R S P I K E ?

CLARK COUNTY FLU UPDATE

IAH

• For all regions except East Central. Week 10 was

high, dipped lower for week 11 and grew larger

again for week 12

THANK YOU !

• Information retrieved from:

Influenza (Flu). (2017, March 31). Retrieved April 03,

2017, from https://www.cdc.gov/flu/index.htm.

Ohio Department of Health Seasonal Influenza

Activity Summary. Retrieved April 5, 2017, from

https://www.odh.ohio.gov/-

/media/ODH/ASSETS/Files/influenza/2016-2017.