Efficacy of face-masks used in Uganda: a laboratory-based inquiry during the COVID-19 pandemic

Background With shortages of face-masks continuing to be reported worldwide, critical questions like whether or not there is an adequate alternative to commercially manufactured face-masks continue to linger especially in low- and middle-income settings. This study aimed at addressing this through testing and comparing various materials and forms of face-masks for filtration efficiency, breathability, microbial cleanliness, distance-dependent fitness, and re-usability of different face-masks procured from face-mask vendors in Kampala, Uganda. Methods This was a laboratory-based descriptive study that applied new protocols and already existing protocols with substantive modifications to ten different types of face-mask types each in quadruplicate to achieve each specified aim. Results Surgical face-masks had better filtration efficiency, distance-dependent fitness and breathability compared to other face-masks tested. Decontamination of these face-masks with 70% ethanol negatively affected their efficacy. Locally-made double layered face-masks had better: filtration efficiency, distance-dependent fitness and breathability compared to other locally-made cloth face-masks, and re-usability compared to all the face-mask types that had been tested. Discussion/conclusions Locally-made double layered cloth face-masks could serve as alternative face-masks especially for populations in low- and middle-income settings like Uganda while allowing restricted use of surgical face-masks and other respirators like the KN95 to high-risk groups only. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial Not applicable ### Funding Statement This work was supported by the Government of Uganda through Makerere University Research and Innovations Fund (RIF) under the RIF Special COVID-19 Research and Innovation Awards- 2020 (Grant #: MAK/DVCFA/151/20). The views expressed herein are those of the author(s) and not necessarily those of the Government of Uganda and Makerere University Research and Innovations Fund. ### 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: Ethical approvals were obtained from the: (1) School of Biomedical Sciences-Research and Ethics Committee, College of Health Sciences, Makerere University (approval number: SBS-793) and the Uganda National Council for Science and Technology (approval number: SS489ES). Written informed consent was obtained from each of the study volunteers before performing the laboratory investigations. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. 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 The datasets generated and/or analyzed during the current study are not publicly available but are available from the corresponding author on reasonable request.