SUBJECT: AN OVERVIEW ON THE TRANSMISSION OF INFLUENZA AND PROTECTION MEASURES RECOMMENDED IN THE EVENT OF A PANDEMIC
ORIGIN: Moldex Technical Services Department
SOURCE: Review of Aerosol Transmission of Influenza A Virus EID Journal Vol 12 (11) November 2006
REVIEWED/UPDATED: August 2021
To protect against a pandemic one must have some understanding of the possible modes of transmission. It is now generally believed that there are three modes of transmission: large droplets generated from coughing and sneezing, aerosols that can remain airborne for long periods of time, and direct contact with infected secretions (called fomites). Complicating the matter is that the transmission of influenzas is not completely understood, and it is likely that transmission may occur from a combination of all three modes.
Coughing and sneezing produces many large droplets, and these large droplets stay airborne for very short periods of time. If a person with a virus sneezes or coughs, the large droplets produced will contain the virus.However, since the droplets are large and stay airborne for a very short period of time, one must be in relatively close proximity to the infected person to become infected. The problem is that these droplets tend to evaporate quickly and, therefore, become aerosols with a smaller particle size. These smaller particles remain airborne for longer periods of time. Some very small particles can remain airborne indefinitely because the air currents in a room will supersede the particles propensity to drop out of the air. Smaller particles can enter the lower respiratory system of a healthy person with ease and infect them.
Protection from these particles appears to be an important factor in reducing the risk of infection, if a pandemic occurs. The CDC, OSHA, and WHO recommend that employees, including healthcare workers, use NIOSH certified respirators at the N95 or higher level. OSHA’s Guidance on Preparing Workplaces for an Influenza Pandemic, dated 2009, recommends the use of N95 or higher rated filters for very high or high exposure risk situations. CDC makes the same recommendations where there is a risk of exposure to these high risk bio-aerosols. Also recommended are supplied air respirators or powered air purifying respirators for certain high risk medical or dental procedures that are likely to generate these bio-aerosols. In all cases, the respirator wearer must be properly fit tested and trained and be part of a comprehensive respiratory protection program.
Employers must plan ahead, if they want to properly protect their employees. The elements of a comprehensive respiratory protection program require some time and forethought and cannot be done in a hasty manner. Consideration must be given to having enough stock of respirators on hand, fit testing the employees, and training them on the proper use. All of this takes time, and consideration must also be given to other PPE and their compatibility with the respirators chosen.
Moldex® offers a complete line of NIOSH certified disposable and half-mask respirators. We offer several different styles of N95, N99, N100, R95, and P100 respirators. Moldex® can also assist you with setting up a respiratory protection program in accordance with 29 CFR 1910.134.
References And Resources
Preparing workplaces for an Influenza Pandemic: https://www.osha.gov/Publications/OSHA3327pandemic.pdf
WARNING: The information contained in this Tech Brief is dated and was accurate to the best of Moldex’s knowledge, on the date above. It is not meant to be comprehensive, nor is it intended to be used in place of the warning/use instructions that accompany Moldex respirators. Outside of the USA, check with all applicable and local government regulations.
©2020 Moldex-Metric, Inc. All Rights Reserved.