What Risks Does the Residential Laundry Process Pose?: A Quantitative Microbial Risk Assessment (QMRA) Study

ABSTRACT

Fomites are an important pathway for infectious disease spread in residential and home healthcare settings (i.e., nursing, assisted living, and retirement communities). Many healthcare professionals launder work clothes at home that may be contaminated by contact with infected patients. Through quantitative microbial risk assessment (QMRA), the study objectives were to (1) evaluate pathogen transmission risks for those doing laundry, and (2) compare infection control interventions to reduce laundering risks. A simulation model was used to evaluate exposure events related to laundry process. One baseline scenario (no handwashing) and three handwashing scenarios (scenario 1 after moving dirty clothes to washing machine, scenario 2 after moving wet clothes to dryer, scenario 3 after both of these previous steps) were evaluated. Each scenario involved a single user, three contacts with contaminated laundry, and three contacts with the face. Five representative microorganisms known to spread via intra-familial transmission were modeled SARS-CoV-2, rotavirus, norovirus, nontyphoidal Salmonella, and Escherichia coli. The mean infection risks for the baseline scenario were all above a 1 in 1,000,000 risk threshold 7.22 × 10