Seasonal and Pandemic (H1N1) Influenza Prevention

Anju Goel, MD, MPHDeputy Public Health Officer

Marin Health and Human ServicesSeptember 30, 2009

Background• Novel flu virus: pig,

human, avian • Identified April 2009• Spreads person to

person • Limited immunity• 1000’s of deaths &

hospitalizations• Pandemic declared

June 2009

Statistics

Cases Hospitalizations Deaths

Marin (9/25/09)

115 3126% ICU

4

CA (9/16/09)

2,01227% ICU

302

Worldwide (9/20/09)

>300,000 lab confirmed

3917 191 countries

Background

• Like seasonal flu– Severity

• Unlike seasonal flu– Different medications– More severe in:

• young• pregnant• chronic medical

conditions

Groups at High Risk

• Children < 5 years• Pregnant women• Chronic illness or

immunosuppression– Cardiac– Metabolic (diabetes)– Pulmonary (asthma)– Neurodevelopmental

• Persons > 65 yrs

2009-10 Flu Season

• Expect seasonal and H1N1 flu

• May have more illness, hospitalizations, fatalities

• H1N1 virus could change– Become more virulent– Become resistant to

medications

Goal: Prevent Spread

• Education• Social Distancing• Medication• Vaccination

School Response Critical

• 1/5 of country’s population

• Half of ill are <18 years• Spreads easily in

young• More severe in young,

esp. <5 years

Education

• Respiratory etiquette– Cover cough/sneeze– Have tissues

available

• Hand hygiene– Wash hands

frequently – Alcohol based hand

sanitizer

Hand Sanitizer• Anti-bacterial, anti-

viral• Use when enter/exit

classroom• When hands not

visibly soiled• > 60% alcohol• Studies show

effectiveness• Monitor allergies

Social Distancing

• The Public Health Practice of encouraging people to keep their physical distance from each other during disease outbreaks in order to slow the spread of infection

Contacts for Teenager 1 (T1)

Stay Home When Sick

• Ill students/staff stay home for 24 hrs after fever resolves [w/o medication]

If Increased Severity

• High risk students/staff stay home• Ill students/staff stay home for longer

period• Students with ill family

members stay home

School Social Distancing

• Rotate teachers instead of students

• Outdoor classes• Cancel/postpone field

trips• Discourage school

buses/public transit• Move desks/classes

School Dismissal

• Types– Reactive: Can’t function normally– Preemptive: Increased severity– Selective: At-risk population

Decision re: Closure

• Pros– Reduced transmission– Reduce

hospitalizations & deaths

• Cons– Social disruption– Missed learning– Nutrition– Job security– Child safety

Medications

• Resistant to adamantanes• Susceptible to oseltamivir, zanamivir

– Used to:• Treat ill persons• Prevent exposed persons from becoming ill

H1N1 Vaccination

• Different from seasonal flu vaccine

• H1N1 vaccine in clinical trials

• Expected availability mid-October

• Number of doses needed TBD

H1N1 Information

• Marin HHS: www.Marinflu.org

• CDC: http://www.cdc.gov/h1n1flu/

• CDPH: http://www.cdph.ca.gov

• WHO: http://www.who.int/en/

Lisa Gelling, MPHPublic Health Preparedness Program

County of Marin Dept. of Health & Human ServicesSeptember 30, 2009

Pandemic (H1N1)2009 Pandemic (H1N1)2009 Update:Update:

Epidemiology in Children

EpidemiologyEpidemiology

“The study of how disease is distributed in populations,

and the factors that influence this distribution.”

Source:  Gordis, L. Epidemiology – 3rd ed. (Saunders, 2004)

Seasonal InfluenzaSeasonal Influenza

Each year in the U.S.:• 200,000+ persons are hospitalized due 

to severity of illness– Approximately 10% of those hospitalized 

cases are children younger than 5 yrs.

• An average of 36,000 deaths are associated with seasonal flu infections

‐About 90% of fatal cases are in older adults     (> 65 yrs.)

Distribution of cases by age group is markedly different compared to seasonal influenza• Higher proportion of hospitalized cases in children and young adults

• Few cases in older adults

Source: ACIP Influenza Workgroup Considerations. ACIP Meeting, July 29, 2009

§

Pandemic Influenza (H1N1): Pandemic Influenza (H1N1): Key Epidemiologic Findings in the U.S.Key Epidemiologic Findings in the U.S.

§

Novel H1N1 Confirmed and Probable Case Rate in the United States, By Age Group

Pandemic Influenza (H1N1): Pandemic Influenza (H1N1): Key Epidemiologic Findings in the U.S.Key Epidemiologic Findings in the U.S.

• Highest incidence of laboratory‐confirmed infections is among school‐age children

Lower immunityHand hygiene

Lack of social distancing

• 0 – 4 year olds have highest hospitalization rates

Epidemiology/SurveillanceHospitalization Rate per 100,000 Population by Age Group (n=7,090*)

2009-H1N1, 08/13/2009Epidemiology/Surveillance

Hospitalization Rate per 100,000 Population by Age Group (n=7,090*) 2009‐H1N1 – 13 AUG 2009

6.1

2.9

1.8 1.9

2.8

0

1

2

3

4

5

6

7

0-4 Yrs 5-24 Yrs 25-49 Yrs 50-64 Yrs ≥65 Yrs

Age Group

Hos

pita

lizat

ions

per

1

00,0

00

Pop

ulat

ion

inA

ge G

roup

n=1288

n=2366

n= 1915

n= 436

n=1085

Pandemic Influenza (H1N1)Pandemic Influenza (H1N1)

CaliforniaOver 25% of cases of H1N1 requiring hospitalization in the ICU have been 

younger than 18 yrs.

Marin County31 hospitalized cases

• Five (16%) were under age 18 (Age range: 2 mos – 5 yrs.)

• None of the hospitalized children required ICU care

•• Pandemic influenza A (H1N1) continues to circulate in our communPandemic influenza A (H1N1) continues to circulate in our community.ity.

Vaccination is the most effective tool • for preventing influenza.

• Vaccinating school‐age children protects them and safeguards the health of people at around them:

• ‐‐ Younger siblings• ~pre‐schoolers, toddlers, infants• ‐‐ Pregnant women• ~ teachers, relatives, mothers of their classmates & friends• ‐‐ Elderly adults• ~ grandparents• ‐‐ Family members and friends with chronic medical conditions

H1N1 Flu Vaccine ProgramChristine Stipp, BSN, PHN

Supervising Public Health Nurse

Vaccine Background• FDA approved

– 6 months and older• Number of doses

TBD• Clinical studies

pending• Multiple formulations

– Nasal– Injected

• No shortage expected

ACIP Priority Groups• Pregnant women• Everyone age 6 months –

24 years• Household

contacts/caregivers of children < 6 months

• Healthcare and EMS personnel

• People 25 - 64 years of age w/chronic medical illness

Priority Groups if Shortage• Pregnant women• Children age 6 months –

4 years• Household

contacts/caregivers of children < 6 months

• Healthcare and EMS personnel

• Children 5 - 18 years of age w/chronic medical illness

Where Can I Get H1N1 Vaccine?

• Healthcare providers• Pharmacies• Public Health flu clinics (if no provider)

– Dates, locations TBD