Seasonal Influenza Update

1

• Seasonal Influenza Update

Donna L. Weaver, RN, MN National Center for
Immunization and Respiratory Diseases
Greensboro, NC September, 2007
2
Disclosures

• The speaker has no financial conflict with the
  manufacturer of any product named in this
  presentation
• The speaker will not discuss the use of influenza
  vaccines in a manner not approved by the U.S.
  Food and Drug Administration (off-label ACIP
  recommendations)
• The speaker will not discuss products not
  currently licensed by the FDA

3
Influenza Infection

• Transmission
• Coughing Sneezing
• Contagious
• 1-2 days before
• symptoms to 4-5 days
• after onset of symptoms
• Severity
• Depends on prior experience with related variants

4
Influenza Illness

• Symptoms
• Abrupt onset of fever
• Sore throat
• Nonproductive cough
• Headache
• General aches pains
• Complications
• Pneumonia
• Reye syndrome
• Myocarditis
• Death 0.5-1 per 1,000 cases

5
Influenza Virus Strains

• Type A - moderate to severe illness - all age
  groups - humans and other animals
• Type B - milder disease - primarily affects
  children - humans only
• Type C - rarely reported in humans - no
  epidemics

6
Influenza Type A Subtypes

• Subtypes of type A determined by two surface
  proteins
• hemagglutinin (H)
• neuraminidase (N)

7
Influenza Antigenic Changes

• Hemagglutinin and neuraminidase antigens change
  with time
• Changes occur as a result of point mutations in
  the virus gene, or due to exchange of a gene
  segment with another subtype of influenza virus
• Impact of antigenic changes depend on extent of
  change (more change usually means larger impact)

8
Surface Antigens and Immunity

• Immunity reduces likelihood of infection and
  severity of disease
• Antibodies are specific to different types of
  surface antigens
• Changes in H and N allow virus to evade
  previously developed immune responses
• Antigenic changes drift and shift

9
Influenza Antigenic Changes

• Antigenic Shift
• major change, new subtype
• caused by exchange of gene segments
• may result in pandemic
• Example of antigenic shift
• H2N2 virus circulated in 1957-1967
• H3N2 virus appeared in 1968 and completely
  replaced H2N2 virus

10

• Influenza Virus Naming Convention

11
2007-2008 Influenza Vaccine Viruses

• A/Solomon Islands/3/2006-like (H1N1)
• NEW
• A/Wisconsin/67/2005-like (H3N2)
• B/Malaysia/2506/2004-like (Victoria)

12
Impact of Influenza, 1990-1999

• Approximately 36,000 influenza-associated deaths
  during each influenza season
• Persons 65 years of age and older accounted for
  more than 90 of deaths
• Average of 226,000 hospitalizations during each
  influenza season

Source MMWR 200756 (RR-6)
13
Month of Peak Influenza Activity United States,
1976-2006
45
19
13
13
3
3
3
Source MMWR 200756 (RR-6)
14
Influenza Vaccine

• TIV
• Trivalent Inactivated Vaccine
• Intramuscular injection
• Persons gt6 months of age
• LAIV
• Live Attenuated Influenza Vaccine
• Intranasal spray
• Only healthy persons 5-49 years of age

15
Inactivated Influenza Vaccine (TIV) Efficacy

• 70-90 effective among healthy persons lt65 years
  of age
• 30-40 effective among frail elderly persons
• 50-60 effective in preventing hospitalization
• 80 effective in preventing death

16
Inactivated Influenza Vaccines (TIV) Available in
2007-2008
vaccines approved for children younger than 4
years
17

• Influenza and Complications Among Nursing Home
  Residents

RR1.9
RR2.0
RR2.5
RR4.2
Inactivated influenza vaccine. Genesee County,
MI, 1982-1983
18
Live Attenuated Influenza Vaccine (LAIV)
Efficacy
Children
Healthy Adults

• 87 effective against culture-confirmed influenza
  in children 5-7 years old
• 27 reduction in febrile otitis media (OM)
• 28 reduction in OM with accompanying antibiotic
  use
• Decreased fever and OM in vaccine recipients who
  developed influenza

• 20 fewer severe febrile illness episodes
• 24 fewer febrile upper respiratory illness
  episodes
• 27 fewer lost work days due to febrile upper
  respiratory illness
• 18-37 fewer days of healthcare provider visits
  due to febrile illness
• 41-45 fewer days of antibiotic use

19
ACIP Influenza Recommendations
http//www.cdc.gov/mmwr/PDF/rr/rr5606.pdf
20
Timing of Influenza Vaccination

• Influenza activity can occur as early as October
• In more than 80 of influenza seasons peak
  activity has not occurred until January or later
• In more than 60 of seasons the peak was in
  February or later

Source MMWR 200756 (RR-6)
21
Timing of Influenza Vaccination

• Immunization providers should begin offering
  vaccine soon after it becomes available and if
  possible by October
• Providers should offer vaccine during routine
  healthcare visits or during hospitalizations
  whenever vaccine is available

Source MMWR 200756 (RR-6)
22
Timing of Influenza Vaccination

• Consider scheduling organized vaccination
  campaigns after at least mid-October
• Scheduling campaigns after mid-October will
  minimize the need for cancellations because
  vaccine is unavailable

Source MMWR 200756 (RR-6)
23
Timing of Influenza Vaccination

• Continue to offer influenza vaccine in December,
  especially to healthcare personnel and those at
  high risk of complications
• Continue to vaccinate throughout influenza season
  (December-March)

24
Influenza Vaccination of Children

• ACIP recommends annual influenza vaccination of
  children 6 thru 59 mos of age (inactivated
  influenza vaccine only)
• Importance of 2 doses for children younger than 9
  yrs of age being vaccinated for the first time
• Children 6 mos thru 8 yrs of age who received
  only 1 dose in their first year of vaccination
  should receive 2 doses the SECOND YEAR they are
  vaccinated
• Children who are in their third or more year of
  being vaccinated and who received only 1 dose in
  each of their first 2 years of being vaccinated
  should continue receiving a single annual dose

Source MMWR 200756 (RR-6)
25

• TIV Vaccdination Schedule

Dose 0.25 mL 0.50 mL 0.50 mL
No. Doses 1 or 2 1 or 2 1
Age Group 6-35 mos 3-8 yrs 9 yrs and older
26
Influenza Vaccination of Adults

• Conditions that increase the risk of influenza
  complications (inactivated influenza vaccine
  only)
• Age
• 65 years and older
• 59 months and younger
• Pulmonary (emphysema, asthma)
• Cardiovascular
• Metabolic (diabetes)
• Renal dysfunction
• Hemoglobinopathy
• Immunosuppression, including HIV infection
• Conditions that compromise respiratory function
  or increase the risk of aspiration

27
Influenza Vaccination and HIV Infection

• Persons with HIV at increased risk of
  complications of influenza
• TIV induces protective antibody titers in many
  HIV infected persons
• Transient increase in HIV replication reported
• TIV will benefit many HIV-infected persons

28
Influenza Vaccination of Adults

• Persons at increased risk of influenza
  complications (inactivated influenza vaccine
  only)
• Residents of long-term care facilities
• Persons 6 months to 18 years of age receiving
  chronic aspirin therapy
• Pregnant women

29
Influenza Vaccination during Pregnancy

• Risk of hospitalization more than 4 times higher
  than among nonpregnant women
• Risk of complications comparable to nonpregnant
  women with high-risk medical conditions
• ACIP recommends vaccination with inactivated
  influenza vaccine for ALL women who will be
  pregnant during influenza season
• Vaccination can occur during any trimester

Source MMWR 200756 (RR-6)
30
Influenza Vaccination of Adults

• Vaccination of household contacts and out-of-home
  caregivers of all children birth through 59
  months of age
• Persons who care for persons at increased risk of
  complications
• healthcare personnel involved in direct patient
  care
• household contacts of persons at risk
• out-of-home caregivers and household contacts of
  children aged lt6 months
• Providers of essential community services
• Foreign travelers
• Students
• Anyone who wishes to reduce the likelihood of
  becoming ill with influenza or transmitting
  influenza to others

31
HICPAC and ACIP Influenza Recommendations for
Healthcare Personnel
http//www.cdc.gov/mmwr/preview/mmwrhtml/rr55e209a
1.htm
32
Influenza Vaccination of Healthcare Personnel
(HCP)

• Healthcare providers, including home care
• Employees of long-term care facilities

33
Benefits of Influenza Vaccination of HCP

• Reduction in nosocomial influenza and
  influenza-related deaths
• Reduction in staff illness and illness-related
  absenteeism
• Reduction of direct medical costs and indirect
  costs from work absenteeism

Source MMWR 200655 (RR-2)
34
Influenza Vaccination of HCP

• Only 42 percent of U.S. healthcare personnel
  were vaccinated in 2004

35
Reasons HCP Do Not Receive Influenza Vaccine

• Concern about vaccine adverse events
• Perception of a low personal risk of
• influenza virus infection
• Insufficient time or inconvenience
• Reliance on homeopathic medications
• Avoidance of all medications
• Fear of needles

Source MMWR 200655 (RR-2)
36
Factors Facilitating HCP Influenza Vaccination

• Desire for self-protection
• Previous receipt of influenza vaccine
• Desire to protect patients
• Perceived effectiveness of the vaccine

Source MMWR 200655 (RR-2)
37
Strategies to Improve HCPInfluenza Vaccination
Levels

• Education
• Role models
• Reduction of financial and time barriers
• Monitor and report influenza vaccination levels
  in the facility
• Signed vaccination declination (?)
• Legislation and regulation (?)

Examples of vaccination declination forms
available in Infection Control and Hospital
Epidemiology, November 2005, and from the
Immunization Action Coalition at www.immunize.org
38
Indications for Live Attenuated Influenza Vaccine
(LAIV)

• Approved only for healthy persons 5 years through
  49 years of age who are not pregnant
• healthcare personnel
• persons in close contact with high-risk groups
• persons who want to reduce their risk of
  influenza

Persons who do not have medical conditions
that increase their risk of complications of
influenza
Source MMWR 200756 (RR-6)
39
Use of LAIV Among CloseContacts of High-Risk
Persons

• Inactivated influenza vaccine (TIV) is preferred
  for close contacts of severely immunosuppressed
  persons who require care in a protective
  environment
• Persons who receive LAIV should refrain from
  contact with severely immunosuppressed persons
  for 7 days after vaccination
• Persons who receive LAIV do not need to be
  excluded from visitation of patients who are not
  severely immunosuppressed

Source MMWR 200756 (RR-6)
40
LAIV Vaccination Schedule

• Number of Doses
• 2
• (separated by 6-10 weeks)
• 1 or 2
• 1

• Age Group
• 5 through 8 years
• -no previous
• influenza vaccine
• -previous influenza
• vaccine
• 9 through 49 years

41
Administration of LAIV

• Severely immunosuppressed persons should not
  administer LAIV
• Other persons at increased risk for influenza
  complications may administer LAIV
• Gloves and masks are not required

e.g., pregnant women, persons with asthma and
persons 50 years of age or older
42
Simultaneous/Non-Simultaneous Administration of
Influenza Vaccine

• Inactivated influenza vaccines (TIV) can be
  administered either simultaneously or at any time
  before or after other vaccines
• LAIV can be administered either simultaneously or
  at any time before or after other vaccines
• Other live vaccines or PPD can be administered on
  the same day as LAIV
• Live vaccines or PPD not administered on the same
  day as LAIV should be administered at least 4
  weeks apart

43
Inactivated Influenza Vaccine (TIV) Adverse
Reactions

• Local reactions 15-20
• Fever, malaise not common
• Allergic reactions rare
• Neurological reactions very rare

44
Live Attenuated Influenza Vaccine(LAIV) Adverse
Reactions

• Children
• no significant increase in URI symptoms, fever,
  or other systemic symptoms
• significantly increased risk of asthma or
  reactive airways disease in children 12-59 months
  of age
• Adults
• significantly increased rate of cough, runny
  nose, nasal congestion, sore throat, and chills
  reported among vaccine recipients
• no increase in the occurrence of fever
• No serious adverse reactions identified

45
Inactivated Influenza Vaccine (TIV)Contraindicati
ons and Precautions

• Severe allergic reaction to a vaccine component
  (e.g., egg) or following a prior dose of vaccine
• Moderate or severe acute illness

46
Live Attenuated Influenza Vaccine(LAIV)Contraind
ications and Precautions

• Children younger than 5 years of age
• Persons 50 years of age and older
• Persons with chronic medical conditions
• Children and adolescents receiving long-term
  aspirin therapy
• Immunosuppression from any cause
• Pregnant women
• Children or adolescents receiving long-term
  therapy with aspirin or other salicylates
• These persons should receive inactivated
  influenza vaccine (TIV)

These persons should receive inactivated
influenza vaccine
47
Live Attenuated Influenza Vaccine(LAIV)Contraind
ications and Precautions

• Severe (anaphylactic) allergy to egg or other
  vaccine components
• History of Guillian-Barré syndrome
• Moderate or severe acute illness

These persons should receive inactivated
influenza vaccine
48
Influenza VaccineStorage and Handling

• Both TIV and LAIV should be stored at
  refrigerator temperature (35o- 46o F) at all
  times
• Neither vaccine should be exposed to freezing
  temperature

49
Influenza Antiviral Use, 2007-2009

• Neither amantadine nor rimantadine should be used
  for treatment or chemoprophylaxis of influenza A
  infections during the 2007-2008 influenza season
• Oseltamivir or zanamivir should be prescribed if
  an antiviral drug is indicated for the treatment
  of influenza

Source MMWR 200756 (RR-6)
50
Big Bird Problem

• H5N1 Avian Influenza
• Human Cases
• 12 countries
• 319 cases
• 192 deaths

http//www.pandemicflu.gov/
51
Influenza Resources
http//www.cdc.gov/flu/
52
Influenza Resourceshttp//www.cdc.gov/vaccines/pu
bs/vis/default.htmflu
53
National Center for Immunization and Respiratory
DiseasesContact Information

• Telephone 800.CDC.INFO
• Email nipinfo_at_cdc.gov
• Website www.cdc.gov/nip
• Vaccine Safety
• http//www.cdc.gov/od/science/iso/