Distributed KN95 Respiratory Face Masks Fail Testing Protocols in South Africa

 
 Twelve KN95 mask brands (total of 36 masks) were evaluated among 7 participants. The mask type and manufacturing details were printed on only 2/12 brands (17%) as per National Institute of Occupational Safety and Health and European Union regulatory requirements. There was considerable variability in the number of KN95 mask layers (between 3 and 6 layers in the 12 brands evaluated). The seal check pass rate was significantly lower in KN95 compared with N95 masks (1/36 (3%) v. 12/12 (100%); p<0.0001). Modification of the KN95 ear-loop tension using head straps or staples, or improving the facial seal using Micropore tape, enhanced seal test performance in 15/36 KN95 masks evaluated (42%). However, none of these 15 passed downstream qualitative fit testing compared with the control N95 masks (0/15 v. 12/12; p<0.0001). Only 4/8 (50%) of the KN95 brands tested passed the minimum filtration requirements for an N95 mask (suboptimal KN95 filtration efficacy varied from 12% to 78%, compared with 56% for a surgical mask and >99% for the N95 masks at the 0.3 μm particle size). 

Source:  K Dheda (keertan.dheda@uct.ac.za) | Full article can be accessed here, http://www.samj.org.za/index.php/samj/article/view/13162

South African Medical Journal 0;0(0):. DOI:10.7196/SAMJ.2021.v111i3.15381

L Mottay,(1)* MB ChB, FCP (SA), Cert Pulmonology (SA); J le Roux,(1),(4)* BSc Hons; R Perumal,(1) MB ChB, FCP (SA) Cert Pulmonology (SA), MPH, MMed; A Esmail,(1) MD, FCP (SA), Cert Pulmonology (SA); L Timm,(4) BEngSc (BME), BScEng (Elec); S Sivarasu,4 PhD; K Dheda,1,2,3 MB BCh, FCP (SA), FCCP, PhD (Lond), FRCP (Lond) 

1 Centre for Lung Infection and Immunity, Division of Pulmonology and UCT Lung Institute, Department of Medicine, Faculty of Health Sciences, University of Cape Town, South Africa 

2 Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, South Africa 

3 Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK 

4 Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa 

*Authors contributed equally 

Mbuso Mothiba

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