Air travel can be daunting, for many a reason. Now add to that a worldwide outbreak of a deadly virus and the fear multiplies tenfold.

Most airports are now screening passengers for symptoms of coronavirus, which started in China's Wuhan. But passengers who have to board a flight can still be weary of being stuck inside a metal box, hundreds of feet above in the sky with fellow passengers sneezing or coughing.

There is still much to learn about the outbreak but scientists do know a bit about similar coronaviruses and other respiratory illnesses like influenza. So how do those viruses spread, specifically on planes? And how can you protect yourself?

The World Health Organization (WHO) defines contact with an infected person as being seated within two rows of one another in an airplane. But passengers do not always stay put in their seats. They move around and go for washroom breaks or walk around to stretch their legs on particularly longer flights. As such, the New England Journal of Medicine noted that the WHO criteria "would have missed 45 percent of the patients with SARS."

During the 2003 outbreak of the severe acute respiratory syndrome (SARS), a passenger aboard a flight from Hong Kong to Beijing infected people well outside the WHO's two-row boundary, reports National Geographic.

This prompted the "FlyHealthy Research Team" to observe the behaviours of passengers and crew on 10 transcontinental US flights of about three and a half to five hours, the report says.

The study was led by Emory University's Vicki Stover Hertzberg and Howard Weiss and they looked at how people moved about the cabin and how that affected the number and duration of their contact with others. The objective was to estimate how many close encounters might allow for transmission during transcontinental flights.

"Suppose you are seated in an aisle seat or a middle seat and I walk by to go to the lavatory. We're going to be in close contact, meaning we'll be within a metre. So, if I'm infected, I could transmit to you...Ours was the first study to quantify this," National Geographic quoted Weiss, professor of biology and mathematics at Penn State University.

The study findings were revealed in 2018 and it said most passengers left their seats at some point, usually to use the washroom or check their overhead bins, during medium haul flights. Understanding the movement of passengers helped scientists to predict the safest places to sit on an airplane.

The passengers who were least likely to get up were in window seats: only 43 percent moved around as opposed to 80 percent of people seated on the aisle, reports National Geographic quoting the study.

However, the team made a model that showed passengers in middle and aisle seats -- even those that are within the WHO's two-seat range -- have a fairly low probability of getting infected.

But all of that changes if the ill person is a crew member as flight attendants spend much more time walking down the aisle and interacting with passengers and are likely to have close, prolonged contact with passengers.

The study found that a sick crew member has a probability of infecting 4.6 passengers, "thus, it is imperative that flight attendants not fly when they are ill."

WHAT DOES THE STUDY MEAN FOR THIS NEW CORONAVIRUS?

Not much is known about the how the new coronavirus transmits yet but earlier cases of similar viruses allow researchers to extrapolate the study findings.

They have concluded that it could transmit primarily through respiratory droplets, physical contact with saliva or diarrhea followed by oral consumption of viral material, or perhaps even aerosols.

As such experts have suggested to follow the guidance by Center for Disease Control on prevention of coronavirus. They are:

-Wash hands regularly with soap or alcohol-based hand sanitizer after touching any surface

-There is evidence that the virus lasts longer on surfaces, making it imperative to wash/sanitize after coming to contact with any surface  

-You should also avoid touching your face and contact with coughing passengers by whatever means possible.