Between October 2024 and January 2025, the UK identified eight cases of Clade Ib Monkeypox virus (MPXV), with seven patients admitted to high consequence infectious disease (HCID) centres. A comprehensive environmental sampling study was conducted to assess the extent of MPXV contamination in isolation rooms and anterooms, focusing on both air and surface samples.

This was a prospective observational study conducted in high consequence infectious disease (HCID) centres across the UK. The aim was to assess environmental contamination by Clade Ib Monkeypox virus (MPXV) in isolation rooms occupied by infected patients. A total of 7 sampling events were undertaken, including 5 during patient occupancy and 2 post-discharge.

The study revealed that MPXV DNA was present in 66 out of 90 surface samples and in one out of 14 air samples. Notably, replication-competent virus was isolated from four surface samples, underscoring the potential for viable virus to persist in patient environments.

Surface contamination was most prevalent on frequently touched items such as bathroom tap handles, shower handles, and toilet flushes. The presence of MPXV DNA in these areas across multiple sampling events highlights the virus’s environmental persistence. Interestingly, higher contamination levels correlated with patients exhibiting moderate to severe symptoms, suggesting a link between clinical severity and environmental viral load.

Air sampling yielded limited detection, with only one positive result during a bed linen change. This aligns with previous studies indicating that transmission of MPXV through the air is less common but possible under specific conditions. The study emphasizes the importance of timing and activity during sampling, as contamination levels varied based on patient presence, time since last cleaning, and room occupancy.

The detection of viable virus in surface samples reinforces the necessity of rigorous IPC measures. Daily cleaning with sodium hypochlorite-based disinfectants proved effective, as only a small fraction of samples contained infectious virus. However, the study raises concerns about IPC in non-healthcare settings, where cleaning and disinfection may be less frequent and materials more porous, potentially increasing transmission risk.

Limitations of the study include variability in patient demographics, disease severity, and sampling timing. Additionally, shared rooms and post-discharge sampling may have influenced contamination levels. Despite these limitations, the findings contribute valuable data to the understanding of MPXV environmental persistence and transmission dynamics.

In conclusion, the study confirms that Clade Ib MPXV can contaminate patient environments with replication-competent virus. While the exact transmission risk remains uncertain, the evidence supports continued emphasis on surface cleaning and disinfection.