Modeling the role of fomites in a norovirus outbreak
Robert A Canales, Kelly A Reynolds, Amanda M. Wilson, Sonia L.M. Fankem, Mark H. Weir, Joan B. Rose, Sherif Abd-Elmaksoud, Charles P Gerba
Community, Environment and Policy
Norovirus accounts for a large portion of the gastroenteritis disease burden, and outbreaks have occurred in a wide variety of environments. Understanding the role of fomites in norovirus transmission will inform behavioral interventions, such as hand washing and surface disinfection. The purpose of this study was to estimate the contribution of fomite-mediated exposures to infection and illness risks in outbreaks. A simulation model in discrete time that accounted for hand-to-porous surfaces, hand-to-nonporous surfaces, hand-to-mouth, -eyes, -nose, and hand washing events was used to predict 17 hr of simulated human behavior. Norovirus concentrations originated from monitoring contamination levels on surfaces during an outbreak on houseboats. To predict infection risk, two dose-response models (fractional Poisson and 2F1 hypergeometric) were used to capture a range of infection risks. A triangular distribution describing the conditional probability of illness given an infection was multiplied by modeled infection risks to estimate illness risks. Infection risks ranged from 70.22% to 72.20% and illness risks ranged from 21.29% to 70.36%. A sensitivity analysis revealed that the number of hand-to-mouth contacts and the number of hand washing events had strong relationships with model-predicted doses. Predicted illness risks overlapped with leisure setting and environmental attack rates reported in the literature. In the outbreak associated with the viral concentrations used in this study, attack rates ranged from 50% to 86%. This model suggests that fomites may have accounted for 25% to 82% of illnesses in this outbreak. Fomite-mediated exposures may contribute to a large portion of total attack rates in outbreaks involving multiple transmission modes. The findings of this study reinforce the importance of frequent fomite cleaning and hand washing, especially when ill persons are present.
Journal of Occupational and Environmental Hygiene
Fomites
Hand Disinfection
Canales, R. A., Reynolds, K. A., Wilson, A. M., Fankem, S. L. M., Weir, M. H., Rose, J. B., ... Gerba, C. P. (2019). Modeling the role of fomites in a norovirus outbreak. Journal of Occupational and Environmental Hygiene. https://doi.org/10.1080/15459624.2018.1531131
Modeling the role of fomites in a norovirus outbreak. / Canales, Robert A; Reynolds, Kelly A; Wilson, Amanda M.; Fankem, Sonia L.M.; Weir, Mark H.; Rose, Joan B.; Abd-Elmaksoud, Sherif; Gerba, Charles P.
In: Journal of Occupational and Environmental Hygiene, 01.01.2019.
Canales, RA, Reynolds, KA, Wilson, AM, Fankem, SLM, Weir, MH, Rose, JB, Abd-Elmaksoud, S & Gerba, CP 2019, 'Modeling the role of fomites in a norovirus outbreak', Journal of Occupational and Environmental Hygiene. https://doi.org/10.1080/15459624.2018.1531131
Canales RA, Reynolds KA, Wilson AM, Fankem SLM, Weir MH, Rose JB et al. Modeling the role of fomites in a norovirus outbreak. Journal of Occupational and Environmental Hygiene. 2019 Jan 1. https://doi.org/10.1080/15459624.2018.1531131
Canales, Robert A ; Reynolds, Kelly A ; Wilson, Amanda M. ; Fankem, Sonia L.M. ; Weir, Mark H. ; Rose, Joan B. ; Abd-Elmaksoud, Sherif ; Gerba, Charles P. / Modeling the role of fomites in a norovirus outbreak. In: Journal of Occupational and Environmental Hygiene. 2019.
@article{d8164ba419234d799aa325f324a94bb4,
title = "Modeling the role of fomites in a norovirus outbreak",
abstract = "Norovirus accounts for a large portion of the gastroenteritis disease burden, and outbreaks have occurred in a wide variety of environments. Understanding the role of fomites in norovirus transmission will inform behavioral interventions, such as hand washing and surface disinfection. The purpose of this study was to estimate the contribution of fomite-mediated exposures to infection and illness risks in outbreaks. A simulation model in discrete time that accounted for hand-to-porous surfaces, hand-to-nonporous surfaces, hand-to-mouth, -eyes, -nose, and hand washing events was used to predict 17 hr of simulated human behavior. Norovirus concentrations originated from monitoring contamination levels on surfaces during an outbreak on houseboats. To predict infection risk, two dose-response models (fractional Poisson and 2F1 hypergeometric) were used to capture a range of infection risks. A triangular distribution describing the conditional probability of illness given an infection was multiplied by modeled infection risks to estimate illness risks. Infection risks ranged from 70.22{\%} to 72.20{\%} and illness risks ranged from 21.29{\%} to 70.36{\%}. A sensitivity analysis revealed that the number of hand-to-mouth contacts and the number of hand washing events had strong relationships with model-predicted doses. Predicted illness risks overlapped with leisure setting and environmental attack rates reported in the literature. In the outbreak associated with the viral concentrations used in this study, attack rates ranged from 50{\%} to 86{\%}. This model suggests that fomites may have accounted for 25{\%} to 82{\%} of illnesses in this outbreak. Fomite-mediated exposures may contribute to a large portion of total attack rates in outbreaks involving multiple transmission modes. The findings of this study reinforce the importance of frequent fomite cleaning and hand washing, especially when ill persons are present.",
keywords = "Fomites, houseboats, norovirus, outbreak, risk assessment",
author = "Canales, {Robert A} and Reynolds, {Kelly A} and Wilson, {Amanda M.} and Fankem, {Sonia L.M.} and Weir, {Mark H.} and Rose, {Joan B.} and Sherif Abd-Elmaksoud and Gerba, {Charles P}",
journal = "Journal of Occupational and Environmental Hygiene",
publisher = "Taylor and Francis Ltd.",
T1 - Modeling the role of fomites in a norovirus outbreak
AU - Canales, Robert A
AU - Reynolds, Kelly A
AU - Wilson, Amanda M.
AU - Fankem, Sonia L.M.
AU - Weir, Mark H.
AU - Rose, Joan B.
AU - Abd-Elmaksoud, Sherif
AU - Gerba, Charles P
N2 - Norovirus accounts for a large portion of the gastroenteritis disease burden, and outbreaks have occurred in a wide variety of environments. Understanding the role of fomites in norovirus transmission will inform behavioral interventions, such as hand washing and surface disinfection. The purpose of this study was to estimate the contribution of fomite-mediated exposures to infection and illness risks in outbreaks. A simulation model in discrete time that accounted for hand-to-porous surfaces, hand-to-nonporous surfaces, hand-to-mouth, -eyes, -nose, and hand washing events was used to predict 17 hr of simulated human behavior. Norovirus concentrations originated from monitoring contamination levels on surfaces during an outbreak on houseboats. To predict infection risk, two dose-response models (fractional Poisson and 2F1 hypergeometric) were used to capture a range of infection risks. A triangular distribution describing the conditional probability of illness given an infection was multiplied by modeled infection risks to estimate illness risks. Infection risks ranged from 70.22% to 72.20% and illness risks ranged from 21.29% to 70.36%. A sensitivity analysis revealed that the number of hand-to-mouth contacts and the number of hand washing events had strong relationships with model-predicted doses. Predicted illness risks overlapped with leisure setting and environmental attack rates reported in the literature. In the outbreak associated with the viral concentrations used in this study, attack rates ranged from 50% to 86%. This model suggests that fomites may have accounted for 25% to 82% of illnesses in this outbreak. Fomite-mediated exposures may contribute to a large portion of total attack rates in outbreaks involving multiple transmission modes. The findings of this study reinforce the importance of frequent fomite cleaning and hand washing, especially when ill persons are present.
AB - Norovirus accounts for a large portion of the gastroenteritis disease burden, and outbreaks have occurred in a wide variety of environments. Understanding the role of fomites in norovirus transmission will inform behavioral interventions, such as hand washing and surface disinfection. The purpose of this study was to estimate the contribution of fomite-mediated exposures to infection and illness risks in outbreaks. A simulation model in discrete time that accounted for hand-to-porous surfaces, hand-to-nonporous surfaces, hand-to-mouth, -eyes, -nose, and hand washing events was used to predict 17 hr of simulated human behavior. Norovirus concentrations originated from monitoring contamination levels on surfaces during an outbreak on houseboats. To predict infection risk, two dose-response models (fractional Poisson and 2F1 hypergeometric) were used to capture a range of infection risks. A triangular distribution describing the conditional probability of illness given an infection was multiplied by modeled infection risks to estimate illness risks. Infection risks ranged from 70.22% to 72.20% and illness risks ranged from 21.29% to 70.36%. A sensitivity analysis revealed that the number of hand-to-mouth contacts and the number of hand washing events had strong relationships with model-predicted doses. Predicted illness risks overlapped with leisure setting and environmental attack rates reported in the literature. In the outbreak associated with the viral concentrations used in this study, attack rates ranged from 50% to 86%. This model suggests that fomites may have accounted for 25% to 82% of illnesses in this outbreak. Fomite-mediated exposures may contribute to a large portion of total attack rates in outbreaks involving multiple transmission modes. The findings of this study reinforce the importance of frequent fomite cleaning and hand washing, especially when ill persons are present.
KW - Fomites
KW - houseboats
KW - norovirus
KW - outbreak
JO - Journal of Occupational and Environmental Hygiene
JF - Journal of Occupational and Environmental Hygiene