Influenza and the Nursing Home Population

Julie L. Freshwater, PhD MPHInfluenza Surveillance Coordinator

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Objectives

•Present provisional data from the 2010-2011 influenza season in the nursing home population

•Understand the term outbreak in the nursing home setting

•Understand the importance of laboratory testing in this population

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Testing for Influenza*• Rapid tests

▫Sensitivities are approximately 50-70%▫Specificities are approximately 90-95%

• Serology▫2 weeks or more

• DFA/IFA▫2 – 4 hours

• Viral Culture▫3 – 10 days

• PCR▫2 – 4 hours*CDC Influenza Diagnostic Table

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OLS Testing for Influenza

•PCR for:▫Influenza

AH3 AH1N1 (SO) B

•When negative for influenza:▫Culture for:

Parainfluenza Adenovirus RSV

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Definition of Influenza-like Illness

Temperature ≥ 100◦ F

AND

Cough and/or

Sore throat

In absence of any other known cause

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LTCF Outbreak Definition

•One (1) positive laboratory test for influenza

in conjunction with other similar illnesses on

the unit indicates an outbreak is occurring

OR

•Three cases of influenza-like illness within

72 hours

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Importance of Laboratory Testing

•Starting or stopping antiviral treatments

•Chemoprophylaxis for residents and staff

•Mitigating morbidity and mortality

•Reducing costs

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If positive for influenza

•Begin prophylaxis on ALL residents • Treatment should continue for 14 days

or for 7 days after onset of symptoms of last person infected

•Unvaccinated staff should receive antiviral treatment

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Importance of positive lab

•Place ill residents in private rooms or cohort with other ill residents

• Ill staff should stay off work until 24 hours without fever

•Keep staff from floating between floors/units

• Implement control measures

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LTCF Outbreak Control Measures•Use standard and droplet precautions

•Attention to hand hygiene

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Additional control measures

•Consider

▫Limiting new admissions

▫Limiting or stopping visitation to the facility

until no new cases for 48 hours

▫Stopping or limiting group activities

▫Serve meals in residents’ rooms

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Specimens for Influenza Testing •Nasopharyngeal swabs

•Obtain 8-10 from recently ill

•Ship to OLS for sub-typing

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Respiratory Outbreaks January-September 2011•51 respiratory outbreaks or clusters•30 in long term care facilities•Clinical Syndrome/Diagnosis:

▫Influenza▫Influenza/Pneumonia ▫Upper or Lower Respiratory Tract Infection▫Pneumonia

•14 counties

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LTCF Influenza Outbreaks January – September 2011 (Provisional Data)

•19 of 30 (63%) respiratory outbreaks were attributed to influenza▫15 of 19 (79% ) lab confirmed ▫4 of 19 (21% ) were rapid test positive with

no confirmatory testing•Only influenza AH3 , no AH1N1 in

residents

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Nursing Home Case #1•Started January 31, 2011 with one rapid

test (+)

•Two more residents on February 12

•Vaccination status of 44 of 73 (60%) staff members unknown

•2 staff members tested positive for influenza, specifics were not available

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Nursing Home #1 Final Count

•5 out 6 specimens sent to OLS for testing were positive for AH3

•14 of 55 (25%) residents met the case definition of ILI

•25 of 73 (34%) staff met case definition

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Nursing Home #2• Illness started February 28, 2011

•19 residents with ILI, 1 rapid test (+)

•8 staff with ILI, 2 rapid test (+)

•46 of 71 (65%) staff members immunized against influenza

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Nursing Home Case #2 Final Count•16/125 residents met case definition

Instead of 19 originally on line list

•14/171 staff met case definition Additional 6 staff members ill from original 8

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Nursing Home #3

• Illness started March 30, 2011

▫10 of 56 residents

▫0 of 35 staff members

•5 were rapid test (+)

•Doctor wanted to just provide anti-virals

for those that were ill

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Nursing Home #3•April 4, 2011

▫26 of 56 (46%) residents were ill 5 residents were sent to the hospital

▫13 of 35 (37%) staff reported illness

•6 specimens were sent to OLS in saline

•Antivirals administered to everyone at this time

•Last onset April 10, 2011

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Nursing Home #3 Final Count

•3 specimens sent to OLS were AH3 (+)

•Five residents hospitalized, two residents

died

•15 of 56 (27%) residents met case

definition

•14 of 35 (40%) staff met case definition

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Conclusion • Influenza symptoms are very similar to

other respiratory diseases•Laboratory testing is essential in

determining etiologic agent▫Results can guide treatment

Antivirals? Antibiotics?

▫Results can guide control measures Respiratory and cough etiquette Restriction of activities enforced or lifted

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