THE BURDEN OF NOROVIRUSES IN HEALTHCARE AND THE ROLE OF HIGH TOUCH SURFACES. Ben Lopman, MSc PhD

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1 THE BURDEN OF NOROVIRUSES IN HEALTHCARE AND THE ROLE OF HIGH TOUCH SURFACES Ben Lopman, MSc PhD

2 Outline The burden of norovirus gastroenteritis In the community In healthcare settings Examples demonstrating the problem of surface contamination CDC guidance 1

3 Challenges relating to the control of norovirus Resistance to disinfection Low infectious dose Rapid symptom onset No culture method Environmental stability Copious shedding Asymptomatic shedding 2

4 Disease Burden #1 cause of acute gastroenteritis in U.S. Nearly 21 million cases annually 1 in 14 Americans become ill each year 71,000 norovirus-associated hospitalizations annually in U.S. 18,500 (26%) in children aged <5 years 28,600 (40%) in elderly aged 65 years Occurs year round, though seasonal peak in activity during winter Found worldwide 3

5 Clinical Disease Incubation period: hours Normal intestine Acute-onset vomiting and/or diarrhea Watery, non-bloody stools Abdominal cramps, nausea, low-grade fever Most recover after hours Virus-infected intestine 10% seek medical attention; some require hospitalization and fluid therapy More severe illness and death possible in elderly and those with other illnesses 30% of infections are asymptomatic 4

6 Viral Shedding Primarily in stool, but also vomitus Peaks 4 days after exposure 100,000,000,000 viruses/g stool viral copies/gram feces 1,000 viruses/id = Occurs for at least 2-3 weeks 10,000,000,000 IDs/g 6,000,000,000 human population = Infectious dose: 18 viral particles Infectivity of shed virus and role of asymptomatic shedding in transmission is unknown 1.6 ID per person/per g stool Teunis et al, 2008 Atmar, EIDJ,

7 Norovirus detection in English IID Study EM Cases Controls RT-PCR 0 under 5 5 to to and older 0 under 5 5 to to and older Amar et al, EJCMID,

8 Community Norovirus Incidence Phillips, AJE,

9 Incidence Studies Crude incidence per 100 person years Community General Practice Phillips 2010 England De Wit 2001 The Netherlands 4.6 Hellard 2001 /Marshall 2003 Australia 9.0 Karsten 2009 Germany 0.6 Hall 2010 USA

10 Total Estimated Norovirus Discharges Norovirus discharges, estimated; 1996 to NOROVIRUS PANDEMIC YEARS

11 Norovirus associated mortality Harris, EIDJ,

12 Etiology of Foodborne Outbreaks Reported to CDC, Other/Multiple 3% Unknown 30% Norovirus 35% Chemicals 5% Parasites 1% Bacteria 26% CDC 2009 & 2010 MMWR 11

13 Characteristics of AGE Outbreaks Reported to CDC by 30 States, Jan 2007-April 2010 Description All States No. (%) All AGE outbreaks 7,734 Suspected norovirus outbreaks 5,737 (74) Suspected norovirus outbreaks Laboratory-confirmed 2,866 (50) Occurring in long-term care facilities 3,532 (68) Person-to-person transmission 3,733 (79) Yen 2010 Caliciviruses Conference 12

14 No. outbreaks Characteristics of Norovirus Outbreaks Reported to CDC by 30 States, Jan 2007-April 2010 Jan-07 Apr-07 Jul-07 Oct-07 Jan-08 Apr-08 Jul-08 Oct-08 Jan-09 Apr-09 Jul-09 Oct-09 Jan-10 Apr Month-Year Yen 2010 Calicivirus Conference 13

15 E&W (584) Netherlands (155) Hungary (119) Finland (85) Spain (54) Germany(118) Setting of norovirus outbreaks in Europe: % 75% 50% 25% 0% Other Food Outlet School/nursery LTCF Hospital Lopman, 2004 Lancet 14

16 Duration of Illness Lopman, CID,

17 Costs of hospital associated norovirus outbreaks Estimates for norovirus infection: United States, 2004 $650,000 [Johnson, CID 2008] 355 cases, 17 weeks Switzerland, 2003 $60,000 [Fretz, Wien Klin Wochenschr, 2008] 16 cases, 2 weeks United Kingdom, 2002/03 - $1 million per 1000 beds, overall $184 million to English National Health Service [Lopman, EID 2004] 3 health systems >3400 cases in 227 outbreaks, 1 year 16

18 ROLE OF HIGH TOUCH SURFACES: THREE STUDIES 17

19 (1) Year-Round Prevalence of Norovirus in the Environment of Catering Companies 42/2,496 (1.7%) kitchen and bathroom swabs tested positive for NoV RNA in OUTBREAK-FREE periods NoV was detected in 147 (39.7%) of the 370 samples for 44 (61.1%) of the 72 establishments associated with outbreaks of gastroenteritis. Boxman et al, AEM

20 (2) Tracking Environmental Norovirus Contamination in a Pediatric Primary Immunodeficiency Unit 2 immunocomprimised patients Long term shedding of GII.3 and GII.4 in both children 116 environments swabs Xerry et al, JCM

21 Possible prolonged environmental survival of norovirus Hospital outbreak 21 cases 5 days Terminal cleaning, including dry vacuuming 13 days after last case; carpet replaced by 2 fitters Diarrhea and vomiting onset 36 & 48 hours later Cheesbrough et al, JHI

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23 Challenges in developing guidelines Little evidence to support cleaning and disinfection of frequently touched surfaces to prevent norovirus No studies directly address the impact of surface disinfection of frequently touched areas on outbreak prevention or containment. Challenge in evaluating basic science data: Trials executed in the lab can use a variety of product formulations, many of which are considered off-label uses (e.g.., concentration, contact times) Some products tested and reviewed for the CDC / HICPAC guideline were not registered for use in the US by the EPA Use of different surrogate models, substrates Many used a 3 log reduction as a benchmark (vs. complete inactivation, 4 log reduction set by EPA) 22

24 Prevention and Control Rapid response and investigation Identify mode of transmission Identify source of contamination Promote appropriate hand hygiene Wash with soap and water 20 seconds Alcohol-based hand sanitizers? 23

25 Virucidal efficacy of 7 hand sanitizers against human norovirus surrogate viruses a Product Ethanol (79%) Ethanol (72%) ph 4.1 Ethanol (72%) ph 2.9 Ethanol (67%) Triclosan (0.1%) Triclosan (0.2%) Chlorhexidine Contact time (minutes) Reduction in titer a MNV Infectivity assay c FCV Infectivity assay 1 > > > > >2.6 d > 3.4 d 5 >2.6 d > 3.4 d > 3.4 d 5 > 2.6 d > 3.4 d > 3.4 d Park et al.,

26 Surface Inactivation Kinetics of Surrogate Viruses in 10% Human Stool Suspension by 5000 ppm of Sodium Hypochlorite at ph 7.0 (a) Infectivity assay (b) RT-PCR assay MS2 ( ), Murine norovirus ( ), Feline calicivirus ( ), human norovirus GII.4 ( ) Park et al 2011, Foodborne Pathogens and Disease, in press 25

27 Prevention and Control Rapid response and investigation Identify mode of transmission Identify source of contamination Promote appropriate hand hygiene Wash with soap and water 20 seconds Alcohol-based hand sanitizers? Prompt and thorough disinfection Bleach solution for contaminated surfaces Other EPA-approved disinfectants? Exclude ill persons hrs after symptom resolution Accommodating sick pay/leave policies 26

28 Conclusions High disease burden of norovirus, particularly in healthcare settings Transmission via environmental, high-touch surfaces important Challenges is developing an evidence base for control New CDC guidelines 27

29 Acknowledgements Norovirus Epidemiology Team Aron Hall Catherine Yen Umesh Parashar National Calicivirus Laboratory GeunWoo Park Jan Vinje 28