What is the risk of flying without a face mask?
After two years of having to wear face masks on flights to and within New Zealand, the requirement has now been lifted.
The government now requires masks to be worn only in healthcare facilities and aged care facilities. Airlines could have continued to enforce their own face mask policies – but Air New Zealand and Jetstar decided to make them optional.
Air New Zealand said its chief medical officer, Dr Ben Johnston, had undertaken a risk assessment and advised it was now appropriate to remove the face covering requirement.
“It also aligns with recent changes to government public health advice and settings,” a spokesperson said.
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Leanne Geraghty, Air New Zealand’s chief customer and sales officer, said in an earlier statement that they “really encourage” customers and staff to keep doing what makes them feel comfortable, and the airline would continue to make masks available.
But how risky is flying without a mask? And how effective is it to wear one when the others on a plane aren’t?
Purify the air
Air transport has been one of the industries hardest hit by Covid-19. Understandably, the industry has been keen to allay fears of flying in a pandemic.
The International Air Transport Association, which represents 290 airlines worldwide, says the risk of contracting Covid-19 on board an aircraft is “very low”.
He explains on most modern jet aircraft, cabin air is approximately 50% fresh air from outside and 50% air that has passed through high-efficiency particulate filters (HEPA ), which are said to be over 99.9% effective at eliminating viruses, bacteria and fungi. Thanks to these systems, the air in the cabin is completely renewed every two to three minutes.
As University of Auckland aerosol chemist Dr Joel Rindelaub has previously said Thingsit is true that airplanes have an advantage over some other forms of public transport or indoor environments due to their superior ventilation systems.
But “low risk” is not “risk free”, and there have been documented cases of transmission of Covid-19 on flights, including a domestic flight in New Zealand.
In September 2020, someone who had just completed 14 days of MIQ caught Covid-19 on a government chartered flight from Christchurch to Auckland. The person was sitting in the row in front of two unknowingly infected people who had also just come out of the MIQ.
The case was written in the United States Centers for Disease Control and Prevention Emerging infectious diseases log.
As good as the ventilation may be when you’re actually in the air, that’s just one aspect of air travel – there’s also the time spent going through security, waiting in the gate room, queuing to board the plane and waiting to get out of the plane.
Researchers at Harvard University looked at ways to reduce public health risks from flying during the Covid-19 pandemic.
In their first report, published in October 2020, they found that the risk of transmission in an aircraft could be reduced to very low levels through a “layered approach”, which took into account the ventilation system, the procedures of disinfection and cleaning of an aircraft, and – above all – passengers wearing face masks.
The authors recommended that passengers and airline employees be required to wear face masks throughout their journey, including time spent at the airport, boarding, in-flight, in the toilet and in the morning. descent from the plane.
“Face masks … are an essential element in preventing the spread of respiratory infectious diseases during travel,” the report said.
“In fact, face mask requirements are perhaps the most essential layer of a comprehensive set of measures to reduce the transmission of Covid-19 throughout air travel.”
It should be noted that this report predates vaccination and widespread infection. The main driver of the Covid figures is now immunity.
As Professor Michael Plank explains: “General measures such as mask mandates in places like retail, schools and workplaces are likely to have a marginal effect on the number of infections. long term. The reason for this is that at any time the vast majority of the population will be immune to the virus and therefore the majority of masks will have little or no effect.
Many countries have removed mask mandates for travel this year. Most U.S. airlines have dropped masking requirements since a federal judge overturned the travel mask mandate in April, while the European Union scrapped its mandatory face mask requirement on flights and at airports in May.
So has there been an increase in Covid cases on flights as a result? It’s hard to say, said Linsey Marr, a Virginia Tech engineering professor who is an expert in the airborne transmission of infectious diseases.
“It’s unclear if there has been an increase in Covid transmission during air travel because I don’t think anyone has tried to look into that,” she said in an email. email to Things.
“In the United States, we have certainly seen an increase in Covid transmission everywhere because of the BA.5 variant. Anecdotally, I’ve heard of many people getting infected while traveling, although it’s unclear if the transmission happened during a flight, in a hotel or restaurant, or elsewhere.
Because there are so many variables, it’s hard to quantify how risky it is to fly without a face mask, she said.
“However, it’s certainly riskier to fly without one than to wear one.”
The right mask
But are you still protected by your mask on a plane if no one around you is wearing one? Experts say yes – according to the mask.
“A good mask can reduce your exposure to airborne virus particles by 95% or more, whether other people around you are wearing a mask or not,” Marr said.
“This will result in a reduction in your risk of becoming infected during the flight.”
Based on studies of masks in other settings, wearing a respirator – such as an N95 or KN95 – was associated with a much lower chance of testing positive for Covid-19.
This means that looking for the surgical masks provided by the airlines may not be very advantageous.
Ben Mullins, an aerosol scientist and professor at the School of Population Health at Curtin University in Perth, said surgical masks were primarily designed to prevent the wearer from emitting virus-laden particles and were generally effective at around 60 % to prevent transmission.
For better protection, people should wear an N95 type mask, which was 90-100% effective.
Rindelaub from the University of Auckland agreed that an N95 type mask was the best option.
“It’s the best way to make sure you’re protected if you decide to wear a mask on a plane.”
To hide or not to hide?
Mullins said the decision to wear a mask would depend on your personal risk profile.
“If you have any pre-existing health conditions — especially vascular or cardiovascular conditions — you should wear the best quality mask possible, regardless of the rules,” he said.
“Healthy, fully vaccinated people might be willing to have a less risk-averse option.”
Marr said that if you mask during the flight, you should also mask at other times during your trip, such as in crowded parts of the airport and on any buses, trains or taxis you take to get to the airport. airport or back, as these also contributed to your exposure.
Rindelaub also said wearing a mask throughout the trip was necessary, given the lack of ventilation in some places.
“Especially if you’re lining up at the terminal trying to get on the plane, there won’t be much ventilation in that hallway,” he said.
“The flight itself – on the plane – has some ventilation to help you, but if there are people near you who are infected, that’s where the risk increases dramatically.”
Wearing a mask, he said, was an easy thing to do to keep you safe – and he would personally continue to do so on all public transport, including flights.
“Just because it’s not required doesn’t mean you shouldn’t do it. It’s always a good idea to mask up when flying.