J Korean Med Sci.  2021 May;36(21):e140. 10.3346/jkms.2021.36.e140.

Fit Test for N95 Filtering Facepiece Respirators and KF94 Masks for Healthcare Workers: a Prospective Single-center Simulation Study

• Park JJ
• Seo YB
• Lee J

• KMID: 2516248
• DOI: http://doi.org/10.3346/jkms.2021.36.e140

Abstract

Background
For protection against coronavirus disease 2019 (COVID-19), the Korean government recommended the KF94 mask or that a mask at the same level as the KF94 should be worn when contacting a patient with COVID-19. Furthermore, adequately fitted N95 respirators and KF94 masks are essential. We investigated the fit tests to determine whether healthcare workers had adequate protection with N95 respirators and KF94 masks.
Methods
In this prospective single-center simulation study, five N95 respirators (two made in the USA by 3M and three made in Korea) and six KF94 masks, the Korean standard medical masks, were tested. The fit factor (FF) and leakage rate were evaluated using a two-fit test device. Adequate protection (defined as FF ≥ 100 or leakage rate ≤ 5) rates were compared between N95 respirators and KF94 masks, and between made in Korea and the 3M N95 respirators. For KF94 masks, adequate protection rates were compared before and after ear strap fixation.
Results
Overall, 30 participants were enrolled, and 330 fit tests were performed for FF and leakage rate. Adequate protection rates of all tested N95 respirators and KF94 masks were 22.7% (n = 75) by FF and 20.6% (n = 68) by leakage rate. N95 respirators showed a significantly higher adequate protection rate than KF94 masks for FF (48.7% vs. 1.1%, P < 0.001) and leakage rate (42.0% vs. 2.8%, P < 0.001). Adequate protection rate of 3M-made N95 respirators was significantly higher than that of those made in Korea (83.3% vs. 25.6% in FF, P < 0.001; 73.3% vs. 21.1% in leakage rate, P < 0.001). In KF94 masks, after fixation of ear strap with a hook, adequate protection rate improved significantly (1.1% vs. 12.8% in FF, P< 0.001; 2.8% vs. 11.1%, P < 0.001).
Conclusion
Although adequate protection rate of N95 respirators was higher than that of KF94 masks, N95 respirator protection rate was not optimum. Thus, it is necessary to minimize exposure to risk by selecting an appropriate mask or respirator that adequately fits each person, and by wearing respirators or masks appropriately, before contacting the patients. With their superior protection rate, wearing N95 respirators is recommended instead of KF94 masks, especially when performing aerosol-generating procedures.

Keyword

Personal Protective Equipment (PPE); N95 Respirators; KF94 Masks; Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

Reference

1. World Health Organization. Timeline: WHO's COVID-19 response. Updated 2021. Accessed January 20, 2021. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/interactive-timeline?gclid=EAIaIQobChMI-qvW15rP7gIVy51LBR02SQ2hEAAYASAAEgJiqfD_BwE#.

2. World Health Organization. WHO coronavirus disease (COVID-19) dashboard. Updated 2021. Accessed January 20, 2021. https://covid19.who.int/.

3. Li Y, Qian H, Hang J, Chen X, Hong L, Liang P, et al. Evidence for probable aerosol transmission of SARS-CoV-2 in a poorly ventilated restaurant. Build Environ. 2021; 196(3):107788. PMID: 33746341.

4. Tang S, Mao Y, Jones RM, Tan Q, Ji JS, Li N, et al. Aerosol transmission of SARS-CoV-2? Evidence, prevention and control. Environ Int. 2020; 144:106039. PMID: 32822927.

5. Centers for Disease Control and Prevention. Interim infection prevention and control recommendations for healthcare personnel during the coronavirus disease 2019 (COVID-19) pandemic. Updated 2021. Accessed January 5, 2021. https://www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control-recommendations.html.

6. Centers for Disease Control and Prevention (CDC). Laboratory performance evaluation of N95 filtering facepiece respirators, 1996. MMWR Morb Mortal Wkly Rep. 1998; 47(48):1045–1049. PMID: 9869077.

7. Han DH. Usage of filtering-facepiece masks for healthcare workers and importance of fit testing. J Korean Soc Occup Environ Hyg. 2015; 25(3):245–253.

8. Kim H, Baek JE, Seo HK, Lee JE, Myong JP, Lee SJ, et al. Comparison of fit factor for healthcare workers before and after training with the N95 mask. J Korean Soc Occup Environ Hyg. 2014; 24(4):528–535.

9. Huh YJ, Jeong HM, Lim J, Park HY, Kim MY, Oh HS, et al. Fit characteristics of N95 filtering facepiece respirators and the accuracy of the user seal check among Koreans. Infect Control Hosp Epidemiol. 2018; 39(1):104–107. PMID: 29345612.

10. McMahon E, Wada K, Dufresne A. Implementing fit testing for N95 filtering facepiece respirators: practical information from a large cohort of hospital workers. Am J Infect Control. 2008; 36(4):298–300. PMID: 18455051.

11. Han DH, Choi KL. Facial dimensions and predictors of fit for half-mask respirators in Koreans. AIHA J (Fairfax, Va). 2003; 64(6):815–822.

12. Wilkinson IJ, Pisaniello D, Ahmad J, Edwards S. Evaluation of a large-scale quantitative respirator-fit testing program for healthcare workers: survey results. Infect Control Hosp Epidemiol. 2010; 31(9):918–925. PMID: 20658919.

13. Regli A, Sommerfield A, von Ungern-Sternberg BS. The role of fit testing N95/FFP2/FFP3 masks: a narrative review. Anaesthesia. 2021; 76(1):91–100. PMID: 32932556.

14. Ministry of Food and Drug Safety. Ministry of Food and Drug Safety Notification No. 2014-153. Updated 2014. Accessed December 31, 2020. https://www.mfds.go.kr/brd/m_207/view.do?seq=8282&srchFr=&srchTo=&srchWord=%EC%95%BD%EC%A0%84&srchTp=0&itm_seq_1=0&itm_seq_2=0&multi_itm_seq=0&company_cd=&company_nm=&page=2.

15. Korea Disease Control and Prevention Agency. Coronavirus Disease-19 Response Guidelines (for local governments) 9–5^th edition. Updated 2020. Accessed December 31, 2020. http://www.cdc.go.kr/board/board.es?mid=a20507020000&bid=0019.

16. Kim MN. What type of face mask is appropriate for everyone-mask-wearing policy amidst COVID-19 pandemic. J Korean Med Sci. 2020; 36(20):e186.

17. Seo H, Kang Bk, Kwon Yi. Fit testing for domestic N95 medical masks. J Korean Soc Occup Environ Hyg. 2020; 30:124–133.

18. Occupational Safety and Health Administration. Appendix A to §1910.134: Fit Testing Procedures (Mandatory). Updated 2019. Accessed January 20, 2021. https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.134AppA.

19. Regli A, von Ungern-Sternberg BS. Fit testing of N95 or P2 masks to protect health care workers. Med J Aust. 2020; 213(7):293–295.e1. PMID: 32893356.

20. Park SH. Personal protective equipment for healthcare workers during the COVID-19 pandemic. Infect Chemother. 2020; 52(2):165–182. PMID: 32618146.

21. Lim T, Lee S, Oh J, Kang H, Ahn C, Song Y, et al. Endotracheal intubation using a direct laryngoscope and the protective performances of respirators: a randomized trial. BioMed Res Int. 2017; 2017:7565706. PMID: 28536701.

22. Shin H, Oh J, Lim TH, Kang H, Song Y, Lee S. Comparing the protective performances of 3 types of N95 filtering facepiece respirators during chest compressions: A randomized simulation study. Medicine (Baltimore). 2017; 96(42):e8308. PMID: 29049235.

23. Kim H, Lee J, Lee S, Oh J, Kang B, Lim TH, et al. Comparison of fit factors among healthcare providers working in the Emergency Department Center before and after training with three types of N95 and higher filter respirators. Medicine (Baltimore). 2019; 98(6):e14250. PMID: 30732139.

24. Kim H, Baek JE, Seo HK, Lee JE, Myong JP, Lee SJ, et al. Assessing real-time performances of N95 respirators for health care workers by simulated workplace protection factors. Ind Health. 2015; 53(6):553–561. PMID: 26320728.

25. Lee MC, Takaya S, Long R, Joffe AM. Respirator-fit testing: does it ensure the protection of healthcare workers against respirable particles carrying pathogens? Infect Control Hosp Epidemiol. 2008; 29(12):1149–1156. PMID: 18980503.

26. McMahon E, Wada K, Dufresne A. Implementing fit testing for N95 filtering facepiece respirators: practical information from a large cohort of hospital workers. Am J Infect Control. 2008; 36(4):298–300. PMID: 18455051.

27. Han DH, Kim HW, Jang YJ, Myong JP, Yang HS, Seo HK. A study on the actual results and draftings regulations of fit testing (I). 2017-969 (in Korean). Updated 2017. Accessed January 20, 2021. https://oshri.kosha.or.kr/oshri/publication/researchReportSearch.do?mode=view&articleNo=408192&attachNo=.

28. Kim H, Baek JE, Seo HK, Lee JE, Myong JP, Lee SJ, et al. Comparison of fit factor for healthcare workers before and after training with the N95 mask. J Korean Soc Occup Environ Hyg. 2014; 24(4):528–535.