Survival of Potential Ebola Virus Surrogates (Bacteriophages Φ6 and MS2) on PAPR Hood Material

One of the main lines of defense protecting healthcare workers from serious pathogens, like Ebola, during patient care is personal protective equipment (PPE). Personal protective equipment is wearable protection items worn by HCW to prevent the spread of disease, both from patient to HCW to patient and from patient to HCW. As PPE is barrier protection; it can become contaminated on its surface during patient care. This poses a risk when it is time to doff PPE at the end of use. Doffing is the detailed process of removing the PPE after patient care. Even with comprehensive training, self-contamination continues to occur. As self-contamination with PPE during the doffing process has been documented through several studies, the question of survivability of infectious diseases on PAPR hoods needs to be investigated. The aim of this study is to determine the recovery and survival of bacteriophages phi6 and MS2 on shroud Powered Air Purifying Respirator (PAPR) material at 45% relative humidity. Each bacteriophage was dried on shroud PAPR hood material coupons at 45% RH over several time points. Survivability was measured by utilizing the double agar layer (DAL) plaque assay method. The projected log reduction calculated from the regression lines for phi6 is estimated to have a ~1 log10 reduction at 24 hours at 45% RH, MS2 is estimated to have a ~1 log10 reduction by 96 hours. MS2 is estimated to only have a .25 log10 reduction at 24 hours at 45% RH. Both bacteriophage MS2 and phi6 survive on shroud PAPR hood material for over 24 hours at 45% relative humidity levels. The results provide evidence that both types of virus survive on PAPR hood material after the longest patient encounter, which is projected to be 8 hours. If a HCW’s PPE were to be contaminated during their patient contact time, the virus is still active once the HCW doffs their PPE and the potential for self-contamination could occur