Aerosolized SARS-CoV-2 transmission risk: Surgical or N95 masks?

Abstract

Based on available evidence, the COVID-19 virus is thought to spread through close contact and droplet transmission. However, some have debated that it could be airborne. Airborne transmission occurs when particles of less than 0.5 μm within droplets spread through exhaled air via a process called aerosolisation. These particles can remain in the air for long periods and can disseminate over distances further than 1 meter. In the context of COVID-19, airborne particles can occur during certain aerosolised-generating-procedures (AGP). WHO underlines the use of N95 respirators or equivalent as part of personal protective equipment (PPE) for healthcare workers (HCW) managing COVID-19 positive patients when aerosolised-generating-procedures (AGP) are being conducted. This retrospective observational study describes the result of COVID-19 reverse transcriptase polymerase chain reaction (RT-PCR) in health care workers (HCW) wearing different form of personal protective equipment (PPE) who had had close contact with a confirmed COVID-19 patient during performing such procedures. All HCWs were quarantined for 14 days after the exposure. COVID-19 RT-PCR nasopharyngeal swabs were performed at different intervals. Little is known about the effectiveness of different types of personal protective equipment (PPE) for preventing SARS-CoV-2 in HCWs. We describe the clinical outcome of HCWs exposed to sudden acute respiratory infection patient before the diagnosis of COVID-19 was known.

Impact of respirator versus surgical masks on SARS-CoV-2 acquisition in healthcare workers: a prospective multicentre cohort

“…Several reports suggest that aerosol transmission is indeed a non-negligible mode of SARS-CoV-2 transmission and that respirators may provide additional protection compared to surgical masks [ 17 – 19 , 21 ]. On the other hand, case reports have suggested that surgical masks are equivalent to respirators in protecting HCW from SARS-CoV-2 infection [ 22 , 23 ]. These supposedly contradictory findings can be reconciled when considering a particular feature of SARS-CoV-2, namely its high overdispersion [ 24 ].…”

P2/N95 respirators & surgical masks to prevent SARS-CoV-2 infection: Effectiveness & adverse effects

“…The majority of the studies were at high risk of bias (n=18/21) ( 16 , 24 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ) primarily due to the potential for recall bias (e.g. use of self-report surveys), participation bias (e.g.…”

“…Twelve studies reported the rate of SARS-CoV-2 infection in HCWs who wore surgical masks compared to those who wore respirators ( 16 , 24 , 26 , 27 , 28 , 29 , 31 , 33 , 35 , 37 , 38 , 40 ). Overall, a similar percentage of HCWs wearing respirators (1,398/15,598 = 8.96%) and surgical masks (1,698/17,947 = 9.46%) acquired SARS-CoV-2 infection ( Fig 2 ).…”

Noninvasive ventilation strategies for patients with severe or critical COVID-19: A rapid review of clinical outcomes

“…It has been suggested that use of non-invasive ventilation strategies may increase transmission of SARS-COV-2 to healthcare workers, placing them at risk during care and adding strain to the healthcare system when isolation is required 2,26 . Although appropriate personal protective equipment may provide adequate protection for some healthcare workers when NIV strategies are used, existing studies are predominantly from early 2020 there is a lack of comparative studies available on this topic [67][68][69][70][71][72][73][74][75][76][77][78] .…”