Transcript Document 7215306

Prevention of Influenza in
Nursing Home Residents:
An Update
Suzanne F. Bradley, M.D.
GRECC - VAAAHS
December 2, 2010
Influenza in LTCF
Objectives
• Significance of influenza/winter viruses
• Update on measures to reduce transmission
– infection control measures
– vaccination
• Antiviral treatment and prophylaxis
Influenza A
Viral Structure
Neuraminidase (N1,N2)
Common Human A Viruses
H1N1,H3N2, H1N2
Hemagglutinin (H1-H3)
RNA
M2 protein
(only on type A)
RNA transcriptases
polymerase
structural proteins
2009 Influenza A (H1N1) Virus - Evolution
Trifonov V et al. N Engl J Med 2009;10.1056/NEJMp0904572
Seasonal Influenza
Mortality and Hospitalization
Hospitalization per 100,000
population
Deaths per 100,000
population
400
350
300
250
200
150
100
50
0
357.9
129.1
65.3
0.3
0.3
0.3
6.3 18.5
33
Age group, years
Thompson WW, et al. J Infect Dis. 2006;194:(suppl 2):S92-S97.
1400
1200
1000
800
600
400
200
0
1195
686
431
321
108
190
21
84
Age group, years
2009 H1N1
Neutralizing Antibodies
• Born 1915 or earlier (n=32)
• Range 91-101 yrs old
– 2-12 yrs in 1918
• 1918 strain Ab (100%)
• Mean titer 1:562 (> 1:40)
• B cells isolated - functional Ab
Yu et al. Nature 2008;455:532
Hancock K NEJM 10.1056/NEJMoa0906453
It is Good to be Old!!!
H3N2
H2N2
H1N1
sw
Year 1918
Age
H1N1
1957
52
91
Immunity
With thanks to Ann Falsey
1968 1977
41
2001
2009
32
H1N1
sw
Influenza Infection
Pathophysiology
Nasopharynx
Trachea
(ciliated respiratory
epithelium)
Lungs (rare)
Pathology of Influenza Infection
Asymptomatic
Bind to respiratory cell
Enter the cell
Symptoms
Rapid replication
Release/cell killed
short incubation period (24-48 hours) /highly contagious
Isolation
Disinfection
Cough
Etiquette
Vaccination
Influenza
Prevention
Education
Influenza
Detection
Antivirals
Hand
Hygiene
Influenza in LTCF
Detection
• Clinical suspicion/flu season
• Serology (2 wks)
• Surveillance cultures (3-7 days)
• Rapid Tests (hours)
– EIA, immunofluorescence, PCR
– nasopharyngeal secretions
Confirmed Influenza
Predictive Symptoms
Symptom (%)
OR (95% CI)
P value*
T >100F
3.26 (3.87-2.75)
<.001
Cough
2.85 (3.68-2.21)
<.001
Congestion
1.98 (2.54-1.54)
<.001
Weakness
1.54 (2.22-1.07)
.008
Anorexia
1.43 (1.86-1.10)
.008
* especially if symptoms severe
Fever+cough PPV 79% NPV 49%
<.001
< 48 hrs
Sensitivity 63% Specificity 67%
Monto et al. Arch Intern Med 2000;160:3243
Older Hospitalized Pts
Influenza Diagnosis
•
•
•
Epidemic influenza documented
Lab confirmed cases
Symptom triad
•
Flu (58%) vs Non-Flu (18%)
– T > 38C, cough, illness < 7 days
– RR 2.99 (95% CI 1.9-4.8)
– sensitivity 78%, specificity 73%
– PPV 47%, NPV 91%
Walsh et al. JAGS 2002;50:1498.
Influenza in LTCF
Rapid Diagnostics-Calgary
•
•
•
•
Controlled study use vs non-use
Test all suspected flu cases
Similar influenza attack rates
Outcomes testing vs non-testing
– Reduction outbreak 9 vs 16 days, p=.03
– No difference use:
amantadine, ATB, labs, isolation,
hospitalizations
Church et al. CID 2002;34:790.
Influenza in Long-Term Care
Interventions
•
•
•
•
Isolation/Social Distancing
symptomatic patients, staff, visitors
cough etiquette
barrier precautions/PPE
Disinfection
fomites, environment,hand hygiene
Antiviral agents
treat cases
prophylaxis exposed
Vaccination - patients, staff
2009 H1N1 Influenza
Hierarchy for Controls In Healthcare Facilities
1. Elimination potential exposures
- pt admissions
- elective procedures
- non-essential or ill visitors
- send ill HCW home
2. Engineering controls
- triage areas/public areas
physical barriers (partitions), limit entry
separate ill from well, protect pts & HCW
- closed suctioning systems
- hands-free dispensers, receptacles
www.cdc.gov/h1n1 (10/14/09)
2009 H1N1 Influenza
Hierarchy for Controls In Healthcare Facilities
3.
4.
Administrative controls/polices
- work place practices and polices
- policies - vaccination, sick leave for HCW
- policies - cough etiquette, hand hygiene, isolation
- triage stations to detect the sick
- dedicated/essential staff for possible/confirmed flu
Personal protective equipment
- lowest priority, last line of defense
- not effective if exposures not recognized
- adherence incomplete
- equipment not used or maintained properly
Influenza Isolation
Droplet Precautions Returns!
•
•
•
•
•
•
•
Standard precautions plus
Large droplets travel ~ 3 ft
Surgical mask within 3 ft pt with RTI sx**
Single room or cohort
Bed placement > 3 ft/curtains
Masks for symptomatic pts outside of the room
Duration isolation 7 days after onset or 24 hrs after
fever/sx resolved which ever is longer*
* except immunocompromised, ** unless aerosols occur
Siegel JD et al. APIC 2007;35:S65-164
Bradley SF. Infect Control Hosp Epidemiol 1999;20:629,
www.cdc.gov/flu/professionals/infectioncontrol
Respiratory Protection
N95 vs Surgical Masks
• Small particles ? role in transmission
•
•
•
•
•
—Ferret/guinea pig models, human outbreaks
Filtration capacity
—Surgical masks
4-90%
—N95 respirators
95-99%
—N95 vs mask efficacy
75% (study retracted)
Limitations
—N95s short supply
—compliance 30%
—N95 no better than masks during H1N1 outbreak/studies
Prioritize use where aerosols likely (bronch, intubation)
Use in addition other preventative measures
CDC issues interim guidance for surgical mask use
Shine KI et al. N Engl J Med 10.1056/NEJM p0908437; MacIntyre CRQ et al. ICAAC Abstract K1918b, 2009; Loeb M et al. JAMA. 2009;302(17):(doi:10.1001/jama.2009.1466)
Seasonal Influenza
Vaccine 2010-2011
• Killed and Live virus vaccines
A/California/7/2009 (H1N1)-like
A/Perth/16/2009 (H3N2)-like
B/Brisbane/60/2008=like
CDC. MMWR 2010;1-61
Influenza in LTCF
Vaccination 2010-2011
•
•
•
All persons > 6 months annually
High risk persons should still be targeted
If vaccine in short supply:
– Ages 6 mo-4 yrs, > age 50 yrs
– Chronic diseases - pulmonary, renal, hepatic,
neurologic, hematologic, metabolic (DM)
– Immunosuppressed
– Pregnancy during influenza season
– BMI > 40
– Native Americans
MMWR 2010;59:1-62.
Influenza in LTCF
Vaccination 2010-2011 (Cont)
• Residents chronic care facilities
• HCW
• Caregivers at risk populations
Influenza in the Elderly
National Health Objective-2010
•
•
•
> 90% vaccination high risk pt
Vaccination rates > age 65 (%)
1973-1985
22-33
1993*
52
2006-08
66
2009
69
NH pts vaccinated
1997
1998
64-82%
83%
* Medicare benefit initiated
Inactivated Vaccines
Influenza 2010-11
•
•
•
•
Afluria
Fluarix
Agriflu
Fluzone High Dose
Approved
> 6 mo
> 3 yrs
> 18 yrs
> 65 yrs
Influenza in LTCF
Fluzone High Dose
•
High-dose Inactivated Vaccine
–
–
–
–
Trivalent injectable
FDA approved > 65 yrs
60 g vs 15 g HA per strain
Higher
• antibody titers
• local injection reactions 36% vs 24%
• fever 1.1% vs 0.3%
– ? protective flu or pneumonia not known
– no recommendation re use
Falsey AR et al. J Infect Dis 2009;2009;200:172; MMWR 59:485, 2010.
Influenza Vaccination in LTCF
Role of HCW Interventions
Cluster RCT - 40 Parisian LTCF (3483 pts)
Post interview vaccination
yes vs no
pt vaccinated
84.3% vs 82.5%
HCW vaccinated
69.9% vs 31.8%
pt mortality all cause
pt ILI
HCW sick leave
OR
0.80
0.69
0.58
CI (95%)
(0.66-0.96)
(0.52-0.91)
(0.36-0.96)
p value
.02
.007
.03
Lemaitre M, et al. JAGS 2009;57:1580; Thomas RE et al. Lancet ID 2006;6:273.
Potter J et al. J Infect Dis 1997;175:1; Carman WF et al. Lancet 2000;355:93;
Influenza Vaccine
Improving Compliance
•
•
•
•
•
•
•
Physician recommendation
Patient reminders
Pre-printed physician orders
Blanket orders
Nurse-initiated
Active declination
National societies endorse mandatory HCW vaccination
Antiviral Resistance
Influenza 2009
CDC Influenza Surveillance Report September 26, 2009
CDC guidance 11/24/2010
Seasonal Influenza
Rx Hospitalized Patients - Mortality
•
•
•
•
Oseltamivir
– > 65 yrs
ICU
Charleson score
Days ill PTA
OR
0.21
0.24
10.5
1.3
0.51
McGeer A et al. Clin Infect Dis 2007 45:1568
P value
.02
<.001
.03
.03
Rx Started
6% - 24 hours
29% - 48 hours
51% - 72 hours
72% - 96 hours
Seasonal Influenza in LTCF
Efficacy Prophylaxis
100
Percent Efficacy
80
60
ILI
Confirmed Flu
40
20
0
Rimantadine
Oseltamivir
Zanamivir
Risebrough et al. JAGS 2005;53:444.
Hirji et al. ICHE 2002;23:604.
Zanamivir (Relenza)
Proper Use (10/9/09)
• Diskhaler use only
• Do not reconstitute in any liquid
• Do not nebulize
– efficacy, safety, stability not established
• Lactose carrier - malfunction ventilator
www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlerts
Influenza
Prophylaxis
• High risk patients
– context of an outbreak
– vaccine contraindicated
– vaccinated late (Rx 2 wks)
– ILI in vaccinated group
– poor antibody response
– caretakers
Influenza
Prophylaxis
• Rx daily for:
– duration outbreak ~ 14 days
– one week after last case
– peak season
– unvaccinated
– outbreak vaccinated pop.
• Rx daily for 2 wks
– post-vaccination
Bradley SF et al. Infect Control Hosp Epidemiol 1999;20:629
Influenza in LTCF
Outbreak - Clinical Definition
• Significance of documented flu in the facility?
•
– attack rates 35-40%
– case-fatality rates ~ 55%
– rapid initiation prophylaxis for the affected ward or entire facility
Normal respiratory infection background rate
– 1 case every 7 days per 40-resident ward
• Likelihood cases unrelated within 72 hrs
– 2 cases ~ 7%
– 3 cases ~ 2%
• If 2-3 cases in 48-72 hrs?
–
–
initiation of isolation procedures
confirmatory rapid testing if feasible in 3-4 pts
– assumes sensitivity test ~ 70%
– if a single pt + declare an outbreak
Hota S et al. Clin Infect Dis 2007;45:1362.
www.cdc.com/flu/professionals/infectioncontrol/longtermcare.htm
www.health.gov.on.ca/english/providers/pub/pubhealth/ltc_respoutbreak.html
Outbreaks in LTCF
What if ILI Continues?
Virus
Season
Influenza
winter
Incubation
days
1-2
RSV
fall-spring
2-8
hMPV
late winter
5-6
PIV
fall-spring
2-8
Coronaviruses
winter
1-3
Rhinovirus
all year
0.3-2
Falsey AR et al. CID 2006;42:518.
Transmission
sm particle
aerosols
lg droplets
fomites
lg droplet
formites
lg droplet
formites
lg droplet
formites
fomites
Outbreaks in LTCF
Non-Influenzal Illness
Virus
Attack
Rate %
LRTI
%
Transfer
%
RSV
42
-
0.1
22-72
18
21-50
31
24
62
100
33
52
27
hMPV
Rhinovirus
Death
Rate %
Culture
(+)
RT-PCR
(+)
14.3
2/22
7/22
5
16.1
-
2/13
0/20
6/13
5/14
38
16
1.8
5
6
21
7/13
4/10
6/19
7/13
Caram LB et al., JAGS 2009;57:482.; Boivin G et al. CID 2007;44:1152.;
Louie JK et al. CID 2007;196:705.; Hicks LA et al., JAGS 2006;54:284.
Outbreaks in LTCF
Co-Circulating Viral Infections
No. Serologic Conversions
250
200
617 residents/13 NH followed 52 wks
paired sera/clinical assessments
PIV-2
PIV-3
229E
OC43
hMPV
Flu B
Flu A
RSV
150
100
50
0
1998
1999
2000
Years
Falsey AR et al. J Am Geriatr Soc 2008;56:1281.
Drinka PJ et al. J Am Geriatr Soc 1999;1087.
All
2009 H1N1 Influenza
Bacterial Co-Infections
• Confirmed H1N1
•
influenza infection
PCR on 77 pt specimens
who died
— S. aureus, S. pyogenes, S.
pneumoniae, H. flu
— 22/77 (29%) evidence
bacteria infection
— 16/21( eligible for 23 valent
vaccine
• Pneumococcal vaccine!
MMWR 2009;58:1071
13%
3%
7%
23%
S. pneumoniae (10)
S. aureus (7)
H. influenzae (1)
34%
20%
S. pyogenes (6)
S. mitis (2)
Multiple (4)
Influenza in LTCF
Priorities in 2010
• HCW vaccination
•
•
– a patient safety issue
– to keep HCW/families healthy & working
Patient vaccination
– still a priority
– role of high HA vaccine?
Antiviral susceptibility remains an issue
– still relying on NA inhibitors
– what strain is circulating can’t be known quickly
– zanamavir administration an issue
Influenza in LTCF
Priorities in 2010
•
•
Isolation continues to be a challenge
–
–
–
–
clarification droplet precautions/surgical masks
lack of private rooms/baths
cohorting, other strategies may be necessary
emergence of resistance in pts on antivirals?
Diagnostic testing - what role?
– rapid accurate PCR tests now available
– improve influenza detection?
– reduce unnecessary antiviral use?
– cost effective?
– how often to screen?
Contact Information
• For questions about this audio conference please contact
Dr. Suzanne Bradley at [email protected]
• For any questions about the monthly GRECC Audio
Conference Series please contact Tim Foley at
[email protected] or call (734) 222-4328
• To evaluate this conference for CE credit please obtain a
“Satellite Registration” form and a “Faculty Evaluation”
form from the Satellite Coordinator at you facility. The
forms must be mailed to EES within 2 weeks of the
broadcast