Virus Survival on Respiratory Protection Equipment Filters

Introduction to Virus Survival

The International Journal of Occupational and Environmental Medicine suggests that the survival of SARS-CoV-2 on filter media of respirators remains undetermined, and there is a potential risk of transmission through fomites 1, 2
Respirators, regardless of type, only trap the COVID-19 virus but do not destroy or inactivate it, according to the International Journal of Occupational and Environmental Medicine 1, 2, 3
The virus's survival on filter media and the potential for fomite transmission remain undetermined, as stated by the International Journal of Occupational and Environmental Medicine 1, 2

The activity of SARS-CoV-2 deposited on different surfaces depends on the material it is attached to, and the duration of its infectious behavior is still being studied, according to Science of the Total Environment 4
Experiments on dry surfaces have shown that a specific proportion of humidity and hydration within droplets ensures the survival of SARS-CoV-2 on solid surfaces, as reported by Science of the Total Environment 4, 5
On SARS-CoV-2-contaminated FFP2 masks, ozone at concentrations above 2000 ppm can disinfect the virus in less than 10 minutes, suggesting that the virus remains viable on these materials without treatment, according to Science of the Total Environment 4, 5

For the reuse of disposable FFR respirators, the worker must remove the respirator and place it in a paper bag, where it will remain for a minimum of 5 days before allowing reuse by the same worker, as recommended by the International Journal of Occupational and Environmental Medicine 6, 7
FFRs cannot be stored in plastic bags unless the plastic has been certified as non-electrostatic, as this will inactivate the electret and the FFR will cease to function, according to the International Journal of Occupational and Environmental Medicine 6, 7

Before each use, the exterior of the filter material must be inspected for physical damage or dirt, as recommended by MMWR Recommendations and Reports 8, 9
If the filter material is physically damaged or dirty, the filter must be replaced (in respirators with replaceable filters) or the respirator must be discarded (in disposable respirators), according to MMWR Recommendations and Reports 8, 9

Various decontamination/sanitization methods, including germicidal ultraviolet irradiation, vaporized hydrogen peroxide, and moist heat, are being evaluated, but to date, there is limited research on the use of these methods, as reported by the International Journal of Occupational and Environmental Medicine 6, 7
Unresolved issues include the duration of treatment required to decontaminate respirators, the availability of necessary equipment, and the adverse effects on filter performance, electret, stitching, exhalation valve, and suspension materials, according to the International Journal of Occupational and Environmental Medicine 6, 7

The following methods must not be used: autoclave, ethylene oxide sterilization, or any process using aggressive chemicals, as they will destroy the integrity of the respirator, as stated by the International Journal of Occupational and Environmental Medicine 6, 7

There are no safe exposure levels for biological aerosols; respirators can reduce inhalation exposures but cannot eliminate the risk of contracting infection or developing disease, according to the International Journal of Occupational and Environmental Medicine 1, 2, 3
In healthcare settings where respirators are used for protection against biological aerosols, the concentration of infectious particles in the air is likely low, so it is unlikely that the filter material will become clogged with material in the air, as reported by MMWR Recommendations and Reports 8
There is no evidence that particles impacting the filter material of a respirator are easily re-aerosolized, according to MMWR Recommendations and Reports 8