Monkeypox Virus Detected on Household Surfaces But Transmission Risk Unclear

Monkeypox virus was detected on household surfaces and objects at the residence of 2 individuals with confirmed infection, suggesting contamination and indirect viral transmission may occur in the home. These findings were published in Morbidity and Mortality Weekly Report.

Two individuals (patients A and B) in Utah were found to have polymerase chain reaction (PCR)-confirmed monkeypox infection in May 2022. After isolating in their shared residence for 20 days, personnel from the Utah Department of Health and Human Services assessed whether the virus had contaminated any objects or high-contact surfaces within their residence.

Initial symptoms in both patients included fatigue and body aches. Eight days following symptom onset, patient A experienced penile lesions, as well as lesions over the lips, hands, lower extremities, and scalp. Patient B reported lesions over the foot, which subsequently spread to the leg and finger after 11 days. The severity of infection was mild for both patients, and the time between symptom onset and resolution was approximately 30 and 22 days for patient A and patient B, respectively.

At the time that specimens were collected from the household, both patients were symptomatic. Prior to specimen collection, the patients noted that they had routinely cleaned and disinfected their residence during the 20-day isolation period. Specimens were collected from 30 household objects and high-contact surfaces within the residence, and subsequently shipped to the Centers for Disease Control and Prevention. The specimens were tested for both West African monkeypox virus and nonvariola orthopoxvirus via real-time PCR assays.

Of the 30 specimens tested via real-time PCR, 21 (70%) were found to have detectable monkeypox virus DNA. These 21 specimens had been collected from cloth furniture, blankets, handles, and switches, as well as a chair and a table. Of note, viral culture results were negative for all 21 specimens.

Although detectable monkeypox virus DNA indicates that some degree of contamination had occurred within the residence, the lack of viable virus suggests that the viability of monkeypox virus may decay over time or via chemical or environmental inactivation. In addition, the disinfection practices performed by the patients during their period of isolation may have reduced the degree of contamination within the residence.

Further studies are needed to investigate the potential risk for indirect monkeypox virus transmission in household environments.

Study authors note that “persons living in or visiting the home of someone with monkeypox should follow appropriate precautions against indirect exposure and transmission by wearing a well-fitting mask, avoiding touching possibly contaminated surfaces, maintaining appropriate hand hygiene, avoiding sharing eating utensils, clothing, bedding, or towels, and following home disinfection recommendations.”

Reference

Pfeiffer JA, Collingwood A, Rider LE, et al. High-contact object and surface contamination in a household of persons with monkeypox virus infection — Utah, June 2022. MMWR Morb Mortal Wkly Rep. Published online August 19, 2022. doi:10.15585/mmwr.mm7134e1