Influenza A (H1N1): contagion lasts 8 days after onset of symptoms

About 15% of people who contract influenza A H1N1 (swine flu) still contagious, eight days after the onset of symptoms, according to researchers from several universities and research centers in Quebec, under the coordination of Dr. Guy Boivin, center CHUL Research, and Gaston De Serres, National Institute of Public Health of Quebec. After 10 days, no such person is still contagious. These results will be presented at the International Congress Interscience Conference on Antimicrobial Agents and Chemotherapy being held in San Francisco.


This study was conducted among members of 65 families in Quebec, from May to July 2009. These preliminary results will be complemented by ongoing studies and compared with those of work elsewhere in the world.

Further analysis of blood is taken in the context of this study aimed at better understanding the immune response of infected persons and to determine the proportion of persons infected who show no symptoms.