"N95" actually describes the filter grade, not the mask/gas mask itself. Masks that reach the N95 level can filter out more than 95% of particles larger than 0.3 microns in diameter.
A meta-analysis shows that in some normal working environments, for medical staff, N95 masks may not be more effective than surgical masks in preventing the spread of acute respiratory infections, although they are more effective in alternative exposure environments.
According to an article published by Jeffrey D. Smith and colleagues from Toronto, Ontario, Public Health, “N95 masks are recommended in some guidelines, and N95 masks are not recommended in some guidelines... Contradictory recommendations from the federal and provincial health authorities have led to The confusion of health care workers may lead to lack of adherence to basic infection control principles and practices.
"Our meta-analysis shows that there is not enough data to determine that in a clinical setting, N95 Protective Masks are better than surgical masks in protecting medical staff from the spread of acute respiratory infections."
The researchers included three randomized clinical trials, one cohort study, and two case-control studies in the systematic analysis. They also analyzed 23 alternative exposure studies. In the meta-analysis of clinical trials, Smith and his colleagues could not determine any significant difference between wearing N95 protective masks and wearing surgical masks for people at high risk of contracting respiratory diseases or influenza-like diseases.
They also observed that there was no difference in absenteeism rates between those wearing N95 masks and those wearing Medical Surgical Masks.
N95 Protective Masks
Alternative Exposure Study
23 alternative exposure studies were analyzed by the Canadian research team. The analysis team reported that “in the laboratory test environment, N95 masks showed less filtration penetration, reduced face seal leakage and reduced overall inward leakage. "That said, Smith and her colleagues warned that the spread of any acute respiratory infection in the workplace may not be easily or accurately replicated in experimental settings, such as alternative exposure studies.
In addition, it is recommended that medical staff wear N95 protective masks to ensure a tight fit with the face, because a better fit is very important for N95 masks. The author warned that if the staff adjusts the protective mask due to discomfort, this "may cause accidental exposure to infection."
They also noticed that, except for a single, randomized controlled trial in the meta-analysis, there was no review of compliance to the intervention, and any reports of respiratory infections were obtained by medical staff from the society, not in the hospital environment.
In addition, the researchers explained that these results do not apply to infections that are mainly transmitted through the air (such as tuberculosis, measles, and chickenpox) or to produce resistance to acute respiratory infections during aerosol treatment. "
The researchers concluded from this that a larger randomized controlled study should be conducted to assess the important difference in the degree of protection provided to medical staff by wearing N95 protective masks vs. Surgical Masks.
Smith concluded, "Randomized controlled trials evaluating the effectiveness of N95 masks in a clinical setting are the most effective information."