Particle sizes of infectious aerosols: implications for infection control

Abstract

The global pandemic of COVID-19 has been associated with infections and deaths among health-care workers. This Viewpoint of infectious aerosols is intended to inform appropriate infection control measures to protect health-care workers. Studies of cough aerosols and of exhaled breath from patients with various respiratory infections have shown striking similarities in aerosol size distributions, with a predominance of pathogens in small particles (<5 μm). These are immediately respirable, suggesting the need for personal respiratory protection (respirators) for individuals in close proximity to patients with potentially virulent pathogens. There is no evidence that some pathogens are carried only in large droplets. Surgical masks might offer some respiratory protection from inhalation of infectious aerosols, but not as much as respirators. However, surgical masks worn by patients reduce exposures to infectious aerosols to health-care workers and other individuals. The variability of infectious aerosol production, with some so-called super-emitters producing much higher amounts of infectious aerosol than most, might help to explain the epidemiology of super-spreading. Airborne infection control measures are indicated for potentially lethal respiratory pathogens such as severe acute respiratory syndrome coronavirus 2.

Ability of fabric face mask materials to filter ultrafine particles at coughing velocity

“…Indeed, analysis of viral particle sizes in individuals with respiratory infections suggests transmission through small particle aerosols, rather than through large droplets, is the rule rather than the exception. 13 The testing apparatus held a 2.5 cm diameter sample of the filter material. The material was allowed to relax on a flat surface and the testing mount placed on top, with excess material secured by an adjustable clip.…”

Comparison of the in vitro-efficacy of different mouthwash solutions targeting SARS-CoV-2 based on the European Standard EN 14476

“…This is based on the efficacy of antimicrobial mouthwashes to reduce the number of microorganisms in the oral cavity prompting a reduction of microorganisms in aerosols [4]. This is particularly interesting, as recent research indicates the relevance of aerosols also in the spread of SARS CoV-2 [5].…”

Improvising the surgical helmet system for aerosol-generating procedures in the OR: Surgeon designed 3D printed mould for augmented filtration system

“…There are several risks in performing surgeries that lead to the production of aerosols. 1,15 In orthopedics nearly, all procedures can be classified as aerosol-generating as most involve the use of the drill, saw, and use of pulse lavage system. Although unproven, it was speculated that the use of positive pressure theatres, space suits, and diathermy during these procedures increased the risks of the spread of infection to healthcare professionals.…”

“…Orthopaedic procedures are traditionally considered aerosolgenerating procedures (AGP). 1,2 Reaming, lavage, and use of saw ( Fig. 1) have all shown to produce aerosols that vary in size from 0.7 to 5 mm 1,3 Surgical helmet systems are routinely used by arthroplasty surgeons to reduce the peri-operative infection rates and were also used as personal protective equipment.…”

“…1,2 Reaming, lavage, and use of saw ( Fig. 1) have all shown to produce aerosols that vary in size from 0.7 to 5 mm 1,3 Surgical helmet systems are routinely used by arthroplasty surgeons to reduce the peri-operative infection rates and were also used as personal protective equipment. 2e4 However, their use during COVID 19 pandemic 5 is not recommended by the manufacturers and the orthopaedic community.…”