Infection prevention and control measures to reduce the transmission of mpox: a systematic review

Objectives To assess the effectiveness of respiratory interventions and case isolation measures in reducing or preventing the transmission of mpox in humans and to inform future focused reviews on mpox transmission. Methods The WHO Clinical Management and Infection Prevention and Control guideline 2022 development group developed three structured research questions concerning respiratory and isolation infection prevention control measures for mpox. We conducted a systematic review that included a broad search of five electronic databases. In a two-stage process, we initially sought only randomized controlled trials and observational comparative studies; when the search failed to yield eligible studies, the subsequent search included all study designs including clinical and environmental sampling studies. Results To inform the questions the review team synthesized route of transmission data in mpox. There were 2420/3924 (61.7%) cases in which investigators identified transmission occurring through direct physical sexual contact. There proved to be no reported mpox cases in which investigators identified inhalation as a single route of transmission. There were 2/3924 (0.05%) cases in which investigators identified fomite as a single route of transmission. Clinical and environmental sampling studies generally failed to isolate mpox virus in saliva, oropharangeal swabs, mpox skin lesions, and hospital room air. Conclusions Current findings provide compelling evidence that transmission of mpox occurs through direct physical contact. Because investigators have not reported any cases of transmission via inhalation alone the impact of respiratory infection prevention control measures in reducing transmission will be minimal. Avoiding physical contact with others, covering mpox lesions and wearing a medical mask is likely to reduce onward mpox transmission; there may be minimal reduction in transmission from additionally physically isolating patients. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This systematic review only used data openly available before the commencement of the review. The full search strategy and all references are contained within the manuscript. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript * ACH : Air changes per hour IPC : Infection Prevention Control RT-PCR : Reverse transcriptase polymerase chain reaction WHO : World Health Organization