the burden of norovirus in schools charles p. gerba, phd departments of soil, water and...
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The Burden of Norovirus in Schools
Charles P. Gerba, PhD
Departments of Soil, Water and Environmental Science & Epidemiology and Environmental Health
University of ArizonaTucson, AZ
We’ll Cover
Norovirus When and where it occurs Case histories Data you can use with your
administrators/school boards Help reduce disease incidence, absenteeism
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Common Infections 80% spread via air, water, food, fomites @800 million cases of respiratory and
enteric infections annually (U.S.) Being around kids means more illness
Unmarried males = one cold per year Unmarried women = 1.3 colds per year Couples with school aged kids = 2.3 colds
each School children =3.5 colds per year.
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Norovirus in the U.S.
21 million people 1.9 million outpatient visits 400,000 ER visits, esp. in young children 71,000 hospitalizations 800 deaths mostly young children and the
elderly
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Norovirus Is One Of The Worst Viruses
Highly contagious Spreads in schools via high touch surfaces Persists on hard surfaces up to 30 days Schools quickly get contaminated Occurs October-May Most school cases go unreported/
unconfirmed
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Role Of Fomites In TransmissionOf A Disease
Sick person sneezes, coughs and pathogens falls on fomite or get aerosolized.
Pathogen falls on fomites e.g. phone, computer
Person picks up pathogen through contaminated fomite. Person touches nose or eyes
with contaminated fingers, becomes infected with pathogen.
Schools –The Perfect Storm Lots of individuals, confined spaces Winter incidence—closed windows High touch areas often not effectively
disinfected Busy hands touch EVERYTHING
Kids touch faces, eyes, mouth 5+ times a minute
Hand washing is not thorough Viral transfer–up to 50% of viruses on a
surface are picked up by the hand when the surface is touched 7
The Perfect Storm, cont’d Most school cases are NOT food-borne Hugh amounts of virus are shed before
symptoms occur Virus on dust particles in the air, settles on
surfaces Disease transmission via 1-10 virus particles.
1 trillion per gram of feces (size of peanut)
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The Hand is Quicker Than The Sneeze
Hand Contact
Adults touch their faces 15.5 times per hour 2.5 eyes 5 nose 8 lip
Children touch their faces 5 times per minute
Teaching: The “Germiest” Profession
Germs per square inch by occupation
5002500450065008500
105001250014500165001850020500
Average All Sites
Highest bacteria per square inch on surfaces commonly touched
Phone, Desk, Computer, Mouse11
Frequently Contaminated SitesIn Schools
Door knobs, handles, push plates Athletic equipment Teaching manipulatives Textbooks/other shared classroom
items Locker handles
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Reported Norovirus Outbreaks
SettingFoodborne Nonfoodborne†
No. % No. %Long-term care facility 12 1 2,060 80School 13 1 148 6Other/Multiple settings 114 13 137 5Hospital 2 0.2 115 4Day care 1 0.1 52 2Restaurant 574 64 38 1
Catering or banquet facility 151 17 8 0.3
Private residence 37 4 32 0.1All settings 904 100 2,590 100
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Site % sites positive for
fecal bacteriaDesks 59Computer mouse 57Cafeteria table 55Library table 53Bathroom sink faucets 36Water fountain 33Keyboards 33Bathroom paper towel dispensers 29
The Most-Frequently Contaminated Sites in Schools
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Average Toilet Seat
Figure 1Top Three Contaminated Sites in All Schools
1.70E+068.60E+05
4.77E+06
1.00E+02
1.00E+03
1.00E+04
1.00E+05
1.00E+06
1.00E+07
Cafeteria Table Computer Mouse Desk
To
tal
Bacte
ria/a
pp
roxim
ate
100 c
m s
q
School Study (Grade K thru 12)- 2009
Impact of Disinfectant Wipes on Absenteeism -Seattle
Study Two school semesters 3rd and 4th graders
Intervention Children’s desk wiped with a disinfectant wipe
at the end of each school day Results
50% reduction in absenteeism
From Bright et al, 2010; J. School Nursing
Our Ohio School Study
Compared classrooms using disinfecting wipes at end of day on each desk
Could we lower incidence of gastroenteritis by treatinghard surfaces?
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The Study Details
Two school semesters 3rd and 4th graders
Classroom surfaces Influenza A virus on up to 50% contaminated Norovirus on up to 22% contaminated
Intervention Quaternary ammonium-based disinfectant
wipes registered for norovirus by EPA Used by teachers on desks at the end of each
school day 18
Results Use of disinfecting wipes reduced
detection of norovirus on hard classroom surfaces
Classrooms that did not use disinfecting wipes had a higher incidence of gastroenteritis
Absenteeism reduced by 50% in classrooms using disinfecting wipes
with EPA registration for norovirus efficacy
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What Do Outbreaks Cost?
Schools closed Lost school days Make-up days might be needed
High absenteeism State reimbursements lost
Teachers and staff ill Replacement personnel needed
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Outbreak Costs, cont’d
Custodial staff often become ill Schools must be disinfected to stop the
outbreak Outside services Extra cleaning materials/supplies
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Non-School (Hidden) Costs Parents stay home from work to care
for sick students Siblings fall ill in sequence
Parents become ill, lose more work time
Virus spreads to work place, community facilities, other schools
Total hidden costs hard to estimate but very high to communities
Medical expenses22
A Real-World Outbreak Staff members and students quickly ill
25+ staff members absent multiple days Spread to other schools and the parochial
school in the community Team activities Extracurricular activities at church (choir, Boy Scouts, first
communion instruction)
Closed 11 schools for one week (school days, one holiday)
5000+ enrollment
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Real-World Outbreak Costs
DIRECT=@$93K Disinfection = $45K
Outside haz mat vendor =$25K Supplies = $10-15K Janitorial staff overtime=$5K
Personnel = $7875 Cost of substitute teachers =$105/day per sub 25 teachers x 3 days
Cancelled class trip=$40K
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Real-World Outbreak Costs
INDIRECT = $1,015,050 School operations = $335,000 per day
Three lost days of school= $1,005,000 State reimbursements = $10,050
3350 x 3+ days out (plus earlier absentees)
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Real-World Outbreak Costs
TOTALS for 2013--Direct and Indirect
$1,093,000
TOTALS--If This Had Occurred In 2014
$2,200,000
(based on state reimbursement policy changes and increased snow days used)
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Virus active one week before closure 50% of student body and staff ill (479
people) Closure “recommended” by the Public
Health Department Closed 7 days for disinfecting
Custodial staff and outside custodial used Disinfected the school, buses
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Norovirus OutbreakReal World Case II
DIRECT COSTS=$43K+ Disinfection= $25,000 Staff costs =$18,000
Substitute teachers $100/day 36 subs/5 days
Norovirus OutbreakReal World Case II
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Indirect Costs Hospitalizations Parents lost time (minimum of six days)
from work
Norovirus OutbreakReal World Case II
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What to Use for Norovirus
Bleach works, but is hard on surfaces Requires personal protective gear (PPG)
Quat-based products are available as liquids, ready-to-use and wipes Can be used on keyboards, mice, all non-
porous surfaces Do not corrode metal PPG is generally not needed
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What Custodians Probably Don’t Know
Reduce illness sharply by disinfecting high touch areas early and often
Buy the right type of product—not all kill norovirus and flu
Read the label and use correctly Reusable cleaning cloths can spread illnesses
Bacteria grow on them, esp in human environments Cloths and other organics reduce disinfectant concentration Hard to get them clean
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Cleaning vs. Hygiene
Cleaning -- “the removal of unwanted matter”
Hygiene -- “reducing the risk of infection” Cleaning alone may increase risks by
spreading pathogens.
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Hospital Cleaning Cloth Study Results
93% of reusable cleaning cloths contained bacteria before use Average number of bacteria = 17,000
37.5 % of the disinfectant soak buckets contained bacteria Average number of bacteria = 523
Cleaning Cloth Material Makes a BIG Difference
Organism Cotton Microfiber P-value
Total bacteria
1,995 24,547 0.01
Coliforms 1 6 0.0002
Molds 1 47 0.001
Cleaning Cloths
Reuseable cleaning/towels/cloth can contain opportunistic pathogens
Washing practices affect microbial loads in reusable cleaning cloths/towels
Microfiber cloths contain more bacteria than cotton
A wide range of enteric bacterial types are present in cleaning cloths
Disease Spread in Offices(Similar to Schools)
Tracer virus on entry door push plates in 80-person office
Within 2-4 hours, 40% to 60% of fomites sampled had virus
Coffee break room is the first to be contaminated
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Hotels Tracer virus (MS-2 virus)
added to hotel room surfaces (i.e. nightstand, desk, doorknob
Sample rooms after maids clean
Sample conference room end of day
Conference attendees’ hands
Hotel Results Virus detected
Next 4 rooms cleaned by the maid On surfaces (table tops) in the conference
room On 1/3 of the conference attendees’ hands On the coffee pot handle
of the break room
Hotels -- Intervention
Intervention Give maids antimicrobial
products, disinfectant wipes for key surfaces
Hand sanitizers for attendees
Results Reduce spread between
rooms by 90% Reduce virus on hands
by 50%
Products That Kill Norovirus Also Kill Ebola In Schools
Nine Texas school districts spent $117,000 to clean schools
$36,000 for cleaning and closed school for three days
$13,000 spent by one school to purchase all new aerosol germicidal sprays
$32,000 spent on supplemental cleaning in one school
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Quat-Based Products “Quats” on the market for 60+ years
Thousands of products but not all work for all pathogens!
30+ quat-based EPA-registered formulations in 1500 products that control norovirus
Our studies in schools show disinfecting with a norovirus-specific quat-based wipe prevents illness These wipes also kill flu virus and other
pathogens 41
Which Quat-Based Products?
Products with this EPA-registration
• Labels indicate which products kill which pathogens
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http://tiny.cc/norovirus-products
Annual Costs for Quat Wipes for Norovirus/Flu
180 school days 30 desks per class
1 wipe for two desks 15 wipes per classroom per day (2700 per
year) Canister is $8.72, contains 160 wipes =
5.45 cents per wipe Cost per year is $147 per classroom
Communication Is the Key Teacher and custodial training is important
Must understand their role in school health Must know the difference between disinfecting,
sanitizing and cleaning Disinfecting is needed the moment illness
strikes The school nurse should be empowered to help
determine when and which high touch areas need to be disinfected
Your districts should see cost savings associated with illness reduction
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Take Home Messages Norovirus and flu are major causes of school
closures, absenteeism Use quat-based disinfectant formulations
registered for efficacy for norovirus and flu Labels state specific pathogens killed by the
product Norovirus is a surrogate for enterovirus, Ebola,
other emerging viral diseases Simple interventions are cost effective ,
reduce transmission of common school-based infections
Follow label directions 45
Questions?
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