Qualitative Assessment of Different Face Masks using Povidone-Iodine in Comparison to Standard Saccharin Method

Abstract

Introduction: The World Health Organisation (WHO) recommends that N95 masks should be used by healthcare workers and patients. Given the shortage, extended use and reuse of masks, it becomes imperative to test the filtration efficacy. Surgical masks and cloth covers should also be assessed for their protection factor, since their use is more prevalent among the general population, and these masks are not certified by National Institute for Occupational Safety and Health (NIOSH). Occupational Safety and Health Administration (OSHA) is the authority for the standard testing and certification of Filtering Face Pieces (FFPs) in the USA; its equivalent in India is the Bureau of Indian Standards (BIS). The BIS recently relaxed the certification guidelines for both N95 and Surgical Masks; thus, even certified masks may prove to be inefficient. Aim: To have an economical method for testing of masks in a hospital setting. Materials and Methods: A cross-sectional study was carried out in a tertiary care hospital in western India, a novel, qualitative (and semiquantitative) function test using an aerosol of iodine solution and detector strips of starch-iodide paper was studied to prove for efficacy of masks by 15 volunteers and various masks of different types (surgical, N95, cloth) over three months. This method provides a rapid, simple and costeffective assessment of respirator efficacy. The test showed 100% sensitivity and 88% specificity. Results: Thirty five masks (N95, Surgical, Cloth and Silver nanoparticle) were tested, N95 – 90% pass the test. Conclusion: Povidone-iodine method is a qualitative assessment which is a crude indicator of mask function as the masks that fail both tests will provide some degree of protection from airborne particles, and concentrations of many respiratory organisms. The N95 masks along with the double masks (surgical and cloth) passed the tests proving their efficacy