Fit-Tested N95 Masks Combined With Portable High-Efficiency Particulate Air Filtration Can Protect Against High...

Area of Science:

• Infection Control and Prevention
• Occupational Health and Safety
• Aerosol Science and Engineering

Background:

• Healthcare workers (HCWs) face significant risk from airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
• Evaluating the efficacy of various masks and personal protective equipment (PPE) is crucial for HCW safety.
• Assessing the potential of high-efficiency particulate air (HEPA) filters to augment existing PPE is a key area of research.

Purpose of the Study:

• To quantify the protective benefits of different masks (surgical, fit-testFAILED N95, fit-testPASSED N95) and PPE against aerosolized viruses.
• To determine if a portable HEPA filter can enhance the protective efficacy of PPE for healthcare workers.

Main Methods:

• Aerosol exposure experiments were conducted using bacteriophage PhiX174 as a surrogate virus.
• A healthcare worker donned PPE (mask, gloves, gown, face shield) and was exposed to nebulized virus in a sealed room.
• Virus exposure was measured using facial and nasal swabs; experiments were repeated with an added HEPA filter.

Main Results:

• Significant virus counts were detected on the face with surgical and fit-testFAILED N95 masks.
• Only fit-testPASSED N95 masks showed a statistically significant reduction in virus counts compared to controls.
• HEPA filtration, when combined with a fit-testPASSED N95 mask and other PPE, reduced virus levels to near-zero.

Conclusions:

• Quantitative fit-testing is critical for N95 respirator effectiveness in reducing viral exposure.
• A combination of fit-testPASSED N95 respirators and HEPA filtration provides substantial protection against high aerosolized virus loads.
• This integrated approach offers enhanced safety for healthcare workers in high-risk environments.