On which mode of transport are you most likely to catch Covid?

Emma Cooke
·12 min read
A train in London - Getty
A train in London - Getty

If you’re hoping to travel (either abroad or domestically) this summer, you may be pondering the best way to actually get to your holiday destination of choice. Transport safety has always been a big question, but since the pandemic, a new element has been added to this – what risk of infection do you expose yourself to aboard each one?

While there hasn’t been a definitive answer to the question, it is possible to look into the main forms – cars, planes, trains, coaches and cruise ships – and weigh the pros and cons of each, which we have done below.

Planes

Evidence suggests that the airborne spread of Covid is a greater danger than surface contact (or fomite transmission). The virus is thought to most often spread through small droplets, called aerosols, being sprayed into the air, and many of the rules brought in around transport have been in response to this, the most obvious being mask wearing.

This is a major point in favour of the safety of aeroplanes, where high efficiency particulate air (HEPA) filters are used to clear and replace the air onboard regularly, removing over 99.97 per cent of bacteria and viruses. A study published last October by the Harvard TH Chan School of Public Health’s Aviation Public Health Initiative said the resulting air was cleaner than in offices or shopping centres.

“Contaminants released in such events [coughing or sneezing] are fully flushed from the cabin in as little as two to five minutes, as opposed to some six hours in a commercial or retail space,” said the report. An over-reliance on these filters can be an issue, however. The study also called for the reduction of passenger numbers onboard, and while many airlines initially started blocking middle seats at the start of the pandemic, few are continuing to do so, instead relying on HEPA filters and masks to keep passengers safe from potentially infected neighbours.

A study last year from Dr. Arnold Barnett, professor of statistics at the Massachusetts Institute of Technology, found that “the risk of contracting Covid-19 from a nearby passenger is about 1 in 4,300,” on US jet aircraft – this fell to one in 7,700 if middle seats were blocked. It is thought that infected people send viral particles into the air at a faster rate than plane systems flush them out, so if you are sat close to someone infected, you still risk catching the virus from them.

Despite this, most experts agree flying itself isn’t very dangerous – a study by the US Transportation Command last October found that with just filters and mask-wearing in place, the risk of exposure to Covid is “very low” and cited that at that time, only “44 documented cases of suspected Covid transmission” had happened onboard an aircraft, and “virtually all of them were in the early months of the pandemic before masks and revised safety protocols came into existence.”

It’s what happens when the plane isn’t in the air that poses the most risk. The same Harvard study strongly recommended strict distancing during boarding and disembarkation, due to the risk of infection. Thankfully, most airlines have heeded this, implementing staggered systems.

The airport is also a risk factor. “Air travel requires spending time in security lines and airport terminals,” states the CDC website, which “can bring you in close contact with other people and frequently touched surfaces”. Airports have implemented enhanced cleaning procedures in response to this and made hand sanitiser widely available, but in the case of the latter you are relying on other people making use of this.

How to stay safe while flying

  • Use hand sanitiser regularly

  • Avoid high-touch or high-traffic areas

  • Maintain social distance while queuing, for instance during boarding and disembarkation

  • Wear a mask

Cars

Ask what form of transport you’re least likely to catch Covid in, and surely a car would spring to most people’s minds – it is a travelling isolation unit after all. This is true in a sense; travelling by car allows you to control exactly who you travel with. However, unless you are travelling solo, it is very much possible to catch Covid in a car.

A few risks are associated with car travel. The first is other passengers. To avoid catching Covid from an infected person, you need to maintain a distance of six feet, something impossible to do in a car – if a member of your travel party starts coughing, you won’t be able to move to a different carriage.

The amount of independence driving allows is another factor. Forms of mass transport are rigorously and regularly disinfected by trained employees, while drivers may be slightly more lax in their standards. For reference, the steering wheel and nearby controls, gearstick, handbrake, door handles, radio controls, elbow rests, seat position controls, door frames and exterior door handles should all be disinfected after use. If you’re in a rental car, thoughts of the other drivers who’ve gone before you may also be a concern. Major companies, such as Avis, Enterprise, and Hertz, have all been adhering to enhanced cleaning and social distancing guidelines upon check-in during the pandemic.

The absence of an eagle-eyed conductor or air steward may also make passengers more comfortable taking off their masks while inside your car, though wearing one may not stop you catching the virus: an early NEJM study in March 2020 reported on a Thai taxi driver who fell ill and tested positive for the coronavirus after driving some tourists who had been coughing, but also wearing masks.

Stops are the final major risk factor associated with cars. On a train, coach or flight, you aren’t responsible for refuelling. Yet if you run low on petrol while driving, you’ll have to pull into a service station, pick up a petrol pump that has potentially been handled by thousands before you, and possibly head into an enclosed building (in which there will other people) to pay. The risk of this proved so high that last September the UK Government started issuing warnings to motorists, advising them to avoid the viral hotspots.

How to stay safe while driving

  • Keep the windows open

  • Make sure the car air system is set to take in outside air instead of recycling it

  • Wear face masks

  • Disinfect the car – particularly high-touch areas – regularly

  • Avoid petrol or service stations

  • Only travel with the same group of people (for instance, not your old school chums one week, then your granny and her knitting circle the next)

Coaches

Not as much research has been done on the statistical risk of Covid transmission on coaches, but many companies have conducted risk assessment and made changes in order to keep passengers safe. National Express, for instance, has introduced pre-boarding temperature screenings, enhanced cleaning, ‘fogging’ (aerosol-based disinfection with an antiviral solution), reduced passenger numbers by half and requires mask-wearing from passengers while at stations and while onboard.

Many coaches also have HVAC (heating, ventilating and air-conditioning) systems similar to those on trains, and are also able to open their windows to enhance ventilation. A study of a bus in China found that a Covid-carrying passenger was able to infect many other passengers, but those seated near windows and doors were at far less risk of transmission.

Passengers onboard also weren’t wearing masks – all coaches now require this, and many have blocked non-window seats to passengers. Filters that remove viruses from the air and can be retrofitted onto air conditioning units are also available – National Express is one such company who uses these.

Shorter journeys – especially those under 15 minutes – decrease the risk of transmission, which is something else to consider if travelling by road (both by coach or car), which can be slower. The drive from London to Manchester, for instance, is roughly two hours longer than going by train.

How to stay safe on coaches:

  • Reduce journey time

  • Wear a mask

  • Choose a window seat, or a seat close to a door

  • Check if an antiviral filter has been installed

Trains

There are conflicting reports around the safety of trains during a pandemic. Research published in BMC Infectious Diseases in 2011 found that those using public transport during flu outbreaks were up to six times more likely to pick up an acute respiratory infection.

Despite this, many reports have found public transport (including trains) to not be responsible for Covid outbreaks. A Rail Safety and Standards Board (RSSB) study carried out in August last year found that the risk of Covid-19 infection at the time was less than 0.01 per cent on an average train journey.

Analysis, done in response to concerns that the public might be assuming roads were safer than rail, showed the risk of contracting Covid-19 while travelling by train was about 1 in 11,000 journeys. This was based on an hour-long train journey in a carriage with no social distancing or face coverings. The report also showed that this risk was more than halved if passengers wore a face covering, which has been mandatory on trains since last July, apart from people who are exempt.

A survey of transportation agencies conducted by The New York Times last August found that in countries where the pandemic had ebbed, train and tube travel had rebounded in large numbers with “no notable superspreader events” occurring as a result. In Tokyo, no infection clusters last year were found to be linked to the city’s rail lines, despite diligent contact tracing. This was also the case in Paris, after a tracing was done on 386 viral clusters between early May and mid-July. A study of Austria’s coronavirus clusters in April and May similarly came back unrelated to public transport.

Measures put in place by rail authorities were named as the reason behind this, with fewer rail users, mask-wearing, and good ventilation all now largely enforced on trains. Limiting passengers is particularly key in reducing the risk of catching Covid on board. Research conducted by the University of Southampton last year found that train users could be infected if sitting within 2.5 metres of someone carrying Covid on a two-hour journey.

Journey time affected this: a journey time of one hour only required a one metre distance to avoid infection. The analysis covered the spread of the virus between December 19 and March 6, 2020 and found that an average of 0.32 per cent of passengers sitting within three seats across and five in front or behind an infected person caught the disease. Passengers travelling in seats adjacent to a sufferer had the highest chance of being infected, at 3.5 per cent. The transmission rate for those on the same row was 1.5 per cent.

How to stay safe on the train

  • Limit journey times

  • Try to keep one metre between yourself and other passengers

  • Wear a mask

  • Keep windows open

Cruises

Cruises garnered a terrible reputation at the beginning of the pandemic, when in February 2020 an outbreak on the Diamond Princess made cruising a poster child for catching Covid. Since then, cruise ships have been grounded, and the stance of the CDC throughout the majority of last year was that cruise ships were a greater risk for Covid-19 transmission than other settings, stating that “cruise ship conditions amplify an already highly transmissible disease”.

Some ocean cruise ships hold thousands of passengers. They use shared facilities like public toilets (outside of those in their cabins), restaurants, casinos and entertainment areas. As such, the risk of passing on an infectious disease isn’t inconsiderable. As the CDC puts it, “high population density onboard ships, which are typically more densely populated than cities or most other living situations,” is a huge contributing factor to fast viral spread. Reducing passenger numbers doesn’t often help either, due to the frequent need for crew members to live and work in close quarters.

On the flip side, this means that cruise ships are generally well-prepared for such instances, with far more comprehensive medical facilities than you would find in a hotel or on a ferry, for instance. Ships also have to maintain a medical crew able to diagnose, care for and evacuate sick patients, if necessary. And outbreak prevention and response protocols have been standard practice on cruise ships far longer than Covid has been around.

This doesn’t change the perception of the risk involved in cruise travel, sadly, and many large cruise ships are still out of operation. Generally, smaller cruise ships in areas where Covid rates are very low have been less problematic. Last year, Germany and Italy allowed cruising to slowly return as Covid cases fell: for instance, MSC Cruises resumed sailing in Europe in August, with solely European guests, and no outbreaks occurred.

The company screened passengers with health questionnaires, temperature screens and a pre-boarding Covid-19 swab test, with no one allowed to board until they cleared all three tests. Guests were only allowed out at ports with an MSC guide on a pre-approved excursion, and if anyone broke the rules while out, they were not allowed back onboard.

How to stay safe on a cruise

  • Choose a smaller ship

  • Travel in an area with a low-Covid rate

  • Choose a company with rigorous passenger screening

As for what the public thinks, in a recent survey by Telegraph Travel, the majority of respondents felt planes were the safest mode of transport, compared to trains, coaches and cruises. Trains came second, cruises third, and coaches, perhaps unfairly, last.

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Which mode of transport would you feel safest on when it comes to your chances of catching Covid? Let us know in the comments.