Be careful, flu doesn’t just spread through sneezing, coughing or by touching contaminated surfaces infected by a flu patient. Breathing the air infected by flu patient may also be responsible to spread the influenza virus.
Exhaled breath from a flu-infected person may also spread the disease through airborne transmission, says a recent study published in the Proceedings of the National Academy of Sciences. The study was launched at the University of Maryland, which involved researchers from the University of Maryland, San Jose State University, Missouri Western State University, and University of California, Berkeley, during the flu season of December 2012 through March 2013.  
“The study findings suggest that keeping surfaces clean, washing our hands all the time, and avoiding people who are coughing does not provide complete protection from getting the flu,” said Sheryl Ehrman, who is now Dean of the Charles W. Davidson College of Engineering at San José State University. “Staying home and out of public spaces could make a difference in the spread of the influenza virus.”
Researchers analyzed breath samples from nearly 140 influenza affected people who had a sore throat and an oral temperature of more than 37.8° Celsius (100.04° Fahrenheit), which is normal oral temperature. Their breath was collected at different spontaneous actions such as during natural breathing, coughing, and sneezing, as well as during prompted speech.
The data analysis showed that the infected people spread the infectious virus in the form of tiny aerosol particles enough to cause airborne transmission of influenza. The aerosol droplets collected from various samples also showed that coughing was not serious enough to spread the disease while sneezing contributed negligibly to spread the virus.
“We found that flu cases contaminated the air around them with the infectious virus just by breathing, without coughing or sneezing,” said lead author of the study Dr. Donald Milton, professor of environmental health in the University of Maryland. “People with flu generate infectious aerosols (tiny droplets that stay suspended in the air for a long time) 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 study contributes in a major way to spread public health awareness and to find out different means of controlling this highly infectious disease, which has been on the rise since past few months.