A Study Quantifying the Hand-to-Face Contact Rate and Its Potential Application to Predicting Respiratory Tract Infection

Abstract

A substantial portion of human respiratory tract infection is thought to be transmitted via contaminated hand contact with the mouth, eyes, and/or nostrils. Thus, a key risk factor for infection transmission should be the rate of hand contact with these areas termed target facial membranes. A study was conducted in which 10 subjects were each videotaped for 3 hr while performing office-type work in isolation from other persons. The number of contacts to the eyes, nostrils, and lips was scored during subsequent viewing of the tapes. The total contacts per subject had sample mean x = 47 and sample standard deviation s = 34. The average total contact rate per hour was 15.7. The authors developed a relatively simple algebraic model for estimating the dose of pathogens transferred to target facial membranes during a defined exposure period. The model considers the rate of pathogen transfer to the hands via contact with contaminated environmental surfaces, and the rate of pathogen loss from the hands due to pathogen die-off and transfer from the hands to environmental surfaces and to target facial membranes during touching. The estimation of infection risk due to this dose also is discussed. A hypothetical but plausible example involving influenza A virus transmission is presented to illustrate the model.

Quantified outdoor micro-activity data for children aged 7–12-years old

“…Incidental ingestion is a primary route of exposure for pesticides, metals including lead and arsenic, flame retardants and microbes (Chisolm Jr and Harrison, 1956;Aung et al, 2004;Jones-Otazo et al, 2005;Zartarian et al, 2006;De Miguel et al, 2007;Morgan et al, 2007;Nicas and Best, 2008). Furthermore clean-up decisions and appropriate risk mitigation actions for hazardous waste sites, including Superfund sites, are based on estimates of the incidental ingestion and dermal exposure pathways (US EPA, 2004).…”

“…Mouthing duration of hands, toys and non-dietary objects also decreased with age among the 1-12-year-old children. However, most current methods to estimate non-dietary ingestion incorporate frequency but not mouthing duration (Zartarian et al, 2000;Canales and Leckie, 2007;Nicas and Best, 2008;Stapleton et al, 2008;Tulve et al, 2010). It is likely with a longer mouthing duration that a greater surface area of the object or hand would be mouthed, which could lead to a greater amount of ingested contaminant.…”

“…In a video observational study of adult office workers, Nicas and Best (2008) reports a median hand-tomouth frequency of 6 events/h (range: 0-24). The results from the current study and from the Nicas and Best (2008) study indicate that the older children and adults may have higher mouthing frequency than the previously published findings (Freeman et al, 2001), which could result in greater non-dietary ingestion exposures than had been previously anticipated in these age groups.…”

“…Non-dietary ingestion exposure has continued to be the primary route for lead and other heavy metal exposure in children (Chisolm Jr and Harrison, 1956;Aung et al, 2004;Zartarian et al, 2006;De Miguel et al, 2007), and is the primary contribution to the polybromindated diphenyl ether body burden of toddlers through adults (Jones-Otazo et al, 2005). Furthermore, non-dietary ingestion exposure is the primary means of transmission for certain infectious diseases like the influenza virus, where exposure occurs through the hand and mouthing contacts with fomites (Nicas and Best, 2008).…”

“…Mouthing and hand contact frequencies are key parameters for estimating non-dietary ingestion and dermal exposure (Zartarian et al, 2006;Nicas and Best, 2008;Stapleton et al, 2008;Julian et al, 2009;Schleier et al, 2009;Macedo et al, 2010;Tulve et al, 2010), as well as soil/dust ingestion rates (Ö zkaynak et al, 2010) critical for most hazardous site clean-up risk assessments including Superfund sites (US EPA, 2004). Several studies have quantified these mouthing and hand contact behaviors in children (Zartarian et al, 1997aBrinkman et al, 1999;Reed et al, 1999;Freeman et al, 2001Freeman et al, , 2005Tulve et al, 2002;AuYeung et al, 2004;Black et al, 2005;Auyeung et al, 2006;Beamer et al, 2008); however, we know of only one other study that has reported any data on children over 6 years of age (Freeman et al, 2001).…”