Viable mpox in the inanimate environmental and risk of transmission

As of August 23, 2023, 30,767 mpox cases have been reported in the United States (https://www.cdc.gov/poxvirus/mpox/response/2022/index.html). Although mpox is primarily transmitted through contact with an infected individual, recent investigations have demonstrated potential mpox transmission from patients to healthcare workers after contact with contaminated bedding ¹ or other fomites. ² In support of such findings, viable mpox virus has been detected on various surfaces in home and hospital settings of infected individuals (Table 1). ^3–8 One quantitative study of viable mpox virus in a residential setting found the highest level on underwear. ³ Viable mpox has been detected on household surfaces for up to 15 days, but at low titers suggesting a lesser potential for transmission. ³ Mpox survival in the environment is highly dependent on surrounding temperature and humidity, ⁹ as well as the porosity of a contaminated object. ³ When mpox mixed with blood or albumin was inoculated on stainless steel at 37°C, no viable mpox could be recovered after 6 and 7 days, respectively, 10 and 11 days, respectively at 22°C, but up to 30 days at 4°C for mpox mixed with either blood or albumin. ⁹

Table 1. Detection of Mpox on Surfaces in Home and Hospital Settings

Based on the data reviewed above, healthcare workers should follow guidance regarding personal protective equipment upon entering the immediate environment of a patient with known or suspected mpox, regardless of whether or not the healthcare worker intends to have direct contact with the patient. ¹⁰ In addition, emphasis should also be placed on careful removal of personal protective equipment to prevent self-contamination while doffing and practicing hand hygiene thereafter. Lastly, cleaning environmental surfaces in the rooms of such patients should be done using products with mpox cidal activity. ^9,10