A new collaborative study suggests that sneezing and coughing is not required for the transmission of the influenza virus, it is easier to spread than previously thought. It is a common perception that you can catch the flu by being exposed to infected droplets in sneezes and coughs or touching surfaces that are contaminated, BUT this study reveals that the flu may be passed on to others simply by just breathing as published in the Proceedings of the National Academy of Sciences.
Evidence has been supplied showing the potential importance of airborne transmission because of the numerous quantities of infectious virus that the researchers have found to be contained in the breath that was exhaled from the participants in this study who were suffering with the flu. It was found that the flu causes the air around the infected individual to become contaminated with the virus just by breathing without sneezing or coughing according to the researchers.
This study was done in collaboration with researchers from the University of Maryland, Missouri Western State University, San Jose State University, University of California, and Berkeley with funding by the National Institutes of Health and the Centers for Disease Control and Prevention.
Researchers captured and characterized influenza virus that was within the breath exhaled from 142 individuals, that had been confirmed to be infected with the flu. Breath collection occurred during prompted speech, natural breathing, sneezing, and spontaneous coughing, and assessed the infectivity of naturally occurring influenza aerosols. 218 nasopharyngeal swabs and 30 minute breathing exhale samples, sneezing, spontaneous coughing on the first, second, and third days after the onset of symptoms were provided by the participants. Analysis of the infectious virus from these provided samples showed that a significant number of influenza patients shed the highly infectious virus routinely into aerosol particles that are small enough to present a real risk for airborne transmission not merely detectable RNA.
48% of the fine aerosol samples acquired in the absence of coughing had detectable viral RNA 72% of which contained infectious virus, suggesting that coughing is not required for infectious aerosol generation in fine aerosol droplets. Sneezes observed were not associated with increased viral RNA copy numbers in either fine or coarse aerosols also suggesting that sneezing does not make a significant contribution to the virus shedding in aerosols.
Keeping surfaces clean, washing hands frequently, and avoiding people who are coughing does not provide complete protection of infection according to this study. Staying home and out of public spaces should make a difference in stopping the virus from spreading.
These findings could be used in the improvement of mathematical models for the risk of airborne influenza virus transmissions from person to person with symptomatic illness to develop and implement more efficient and effective public health interventions to help control and ideally reduce the impact of the influenza virus pandemics and epidemics. Simple improvements could be made to ventilation systems to help reduce the risk of transmission in schools, subways, and offices as an example. The best advice is still to stay at home, especially in the beginning when starting to get sick to prevent even greater numbers of flu cases. Vaccination is far from perfect, but in some cases does prevent illness, do research on the subject to decide if the benefits, risks and side effects associated are right for you.
