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Flu can spread just through breathing

Research into breath particles shows that flu spreads more easily than previously thought.

It is commonly believed that flu is spread through coughs and sneezes, and from touching contaminated surfaces. However, a new study in people with flu has found clear evidence that normal breathing – without coughing or sneezing – releases tiny particles into the air that can infect other people.

Breath analysis

Flu is an extremely contagious respiratory illness caused by influenza viruses. This study, led by researchers at the University of Maryland, aimed to better understand how flu is transmitted.

To examine this, 142 people with confirmed flu infection sat in a machine that captured their breath during 30-minute sessions carried out on the first three days after their symptoms emerged.

Participants were asked to breathe, talk, cough and sneeze naturally, which generated clouds of different sized virus-containing particles that were collected for analysis.

Infectious droplets

Previously, many researchers thought that it was the larger particles, such as those generated through coughs and sneezes, that mainly spread the flu virus. However, this study found that a significant number of flu patients regularly exhaled the virus via tiny droplets that stay suspended in the air for a long time, known as 'aerosols'.
Surprisingly, 11 (48%) of the 23 smallest aerosol samples that were collected when people breathed without coughing had detectable levels of the flu virus, and most of those were infectious. This suggests that coughing was not necessary for infection to occur via aerosols. Sneezing was also found not to be important for transmitting the flu virus through aerosols.

These valuable findings highlight the importance of ‘airborne’ transmission of flu and imply that hand washing and avoiding people who are coughing or sneezing does not provide adequate protection against infection.

Reducing spread

The authors suggest that the study results, published in the journal Proceedings of the National Academy of Sciences, could help to improve mathematical computer models that analyse the risk of flu being transmitted through the air.

In addition, the results could feed into developing more effective public health initiatives to control and reduce flu pandemics and epidemics. Lead Researcher Professor Milton said: “People with flu generate infectious aerosols even when they are not coughing, and especially during the first days of illness. So when someone is coming down with influenza, they should go home and not remain in the workplace and infect others.”

The findings also suggest that improving ventilation in offices, schools and other public places might help to reduce the spread of flu.

This article was written by a third party source and does not reflect the views or opinions of Ramsay Healthcare unless explicitly stated.

Additional comments on the page from individual Consultants do not necessarily reflect the views or opinions of other Consultants or Ramsay Healthcare.

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