What is close contact?

From Interim Recommendations for Facemask and Respirator Use in Certain Community Settings Where Swine Influenza A (H1N1) Virus Transmission Has Been Detected, a definition of “close contact”:

Three feet has often been used by infection control professionals to define close contact and is based on studies of respiratory infections; however, for practical purposes, this distance may range up to 6 feet. The World Health Organization uses “approximately 1 meter”; the U.S. Occupational Safety and Health Administration uses “within 6 feet.” For consistency with these estimates, this document defines close contact as a distance of up to 6 feet.


Ken's picture
Ken on April 27, 2009 - 21:04 Permalink

How far can sneeze propelled mucus fly?

Peter Rukavina's picture
Peter Rukavina on April 27, 2009 - 21:20 Permalink

From Interim Infection Control Guidelines for Pandemic Influenza in Healthcare and Community Settings:

Droplet transmission occurs when large (greater than or equal to five micrometre diameter) droplets are generated, propelled a distance of up to one metre and deposited on the mucous membranes or conjunctivae (mouth, nose or eyes) of another person. Transmission via large droplets requires close contact as the droplets do not remain suspended in the air and generally only travel short distances (usually a metre or less).
Chuck's picture
Chuck on April 28, 2009 - 18:14 Permalink

This is useful information even if the fear of swine flu is likely overblown. See this CMAJ article from a few years ago that puts the estimates of annual influenza deaths in Canada at somewhere between 700-2500 per year. That’s quite a few people from the “garden variety” flu, but because we’re familiar with it, we don’t notice. It’s the novelty that allows swine flu to make the news.