How COVID-19 & Other Diseases Spread Through Travel

In the wake of COVID-19, we've seen a spike in pandemic-related media consumption over the past couple months, as evidenced not only by 24-hour news coverage across countless outlets, but also by the fact that films like Contagion and Outbreak, though dated, have recently been climbing the charts worldwide.

The novel coronavirus pandemic is clearly at the forefront of everyone's minds, and has become a source of widespread fear. Much of this anxiety stems from how much remains unknown about the virus and about what the future will hold. What might bring us some comfort and stability are the things we do know and have control over—practicing good hygiene, self-quarantining, and social distancing, for example—as well as the actions we can take to protect ourselves when we must go out into the world.

As horrifying as the opening scenes of Contagion might be, they demonstrate how easily diseases can spread from person to person and population to population via transportation, and are an important reminder that we should take extra precautions to protect ourselves and others when in transit. Whether you need to drive, share a ride, or take public transportation, here are some guidelines to keep in mind.

Insidious Sources of Infection

If a person is coughing, sneezing, or even just clearing their throat, it’s easy to assume that they are a potentially infected individual and therefore someone to avoid. But the thing is, there are other sources of infection that can be more difficult to discern—yet are just as dangerous.


A carrier is any human or animal that harbors an infectious agent (such as a virus) and has the ability to transmit the infection to other people despite not appearing to be sick or not exhibiting symptoms.


Fomites are inanimate objects that have been contaminated with an infectious agent. Like carriers, these items have the ability to infect or transfer diseases. If not sanitized properly, they will remain infectious for a certain period of time.

Common Modes of Transportation in the U.S.

According to the American Public Transportation Association Americans use public transportation a staggering 34 million times each weekday. The most commonly utilized modes of public transportation in the U.S. include subways, buses, ferries, tramways, and many others.

In the midst of disease outbreaks, commuters who regularly utilize public transit may be more susceptible to infection due to the enclosed nature of these vehicles.

To quell the fears of the riding public, transportation companies have come out with outlined plans to help mitigate infection, citing enhanced sanitization procedures and regular air filter maintenance. Nonetheless, being in confined or close quarters with other passengers poses a risk that cannot be avoided.

Global health agencies recommend “social distancing” as a precautionary measure to help minimize the spread of infectious diseases within communities—but that can be pretty hard to do when you’re riding a packed subway car or bus every day.

Many Americans opt for ride-sharing services nowadays, but these are not necessarily safer than public transit. Contagious droplets, too small to be detected by the naked eye, may collect on various parts of a car and be transferred to the next passenger.

Drivers themselves, if they’re sick, may potentially act as disease vectors. Traveling in a car with a person infected with the seasonal flu can increase your risk of getting sick up to 99.9%

Protecting yourself from COVID-19 and other illnesses requires a clear understanding of where viruses and other germs tend to live or breed, not just in your immediate surroundings, but inside the vehicles we drive or the public transportation we ride during our daily commutes.

In this article, we explore how infection can occur in various modes of transportation, and how you can protect yourself from the unseen pathogens that surround us when we travel.

Subways and Trains

In New York, people take over 8,700,000 subway trips every weekday. Millions more around the country, both locals and tourists, use subways to go to work or visit places.

Unfortunately, underground railway systems can become the perfect venues for the rapid transmission of diseases that anybody could end up taking home with them.

The subway is filled with nonporous surfaces that allow viruses to remain viable for several hours to a few days post-contact. Researchers from the National Institutes of Health (NIH), Centers for Disease Control (CDC), Princeton, and UCLA recently published a medical study that examined the stability of the HCoV-19 virus on various surfaces. Their research found that the virus was “most stable on plastic and stainless steel and viable virus could be detected up to 72 hours post application.”

Here’s the problem—most of us are accustomed to mindlessly touching safety rails and other surfaces as we navigate the subway station crowds. How many times have you clutched the handrail on the escalator, which countless before you have touched? Or how about when you reload your MetroCard and press the touchscreen on the vending machine, or when you grasp the steel poles on the train when you can’t get a seat?

Before the COVID-19 outbreak, most commuters wouldn’t have thought twice about the daily physical contact they would have with all sorts of surfaces on public transit. We’re all probably a bit more wary now about touching things, but some habits are truly hard to break. You might still instinctively grab at a hanging strap or a grab rail to steady yourself as you walk to the door of the subway car.

If you commute every day, there’s simply no way around it—you expose yourself to all kinds of bacteria and viruses, which you would inevitably carry with you once you disembark.

This then leads to more potential transmission events.

How many times have you clutched the handrail on the escalator, which countless before you have touched?

But aside from touching contaminated surfaces, the most notable factor that can play a role in disease transmission within public transit are the people themselves.

According to the same study cited above, aerosolized respiratory secretions from coughing and sneezing remain viable for up to three hours, which means that the droplets that remain in the air from someone’s uncovered sneeze can still infect someone long after they’ve disembarked.

It’s not a scare tactic. Researchers have proven that confined and crowded environments like subways and trains can act as hotspots for spreading diseases.

“The risk of transmission does seem to be highest in unventilated locations,” says World Health Organization Special Envoy for COVID-19 Dr. David Nabarro. “[Transmission occurs through] microscopic droplets that we produce when we cough or sneeze. That’s why it's important that the nose and mouth are covered when coughing.”

A study by a team from the University of Bristol found that travellers who had longer journeys using the London Underground (the public rapid transit system serving the London region) through busier terminals had higher rates of airborne infections from flu-like illnesses.

The findings were similar to the results of a study on the 2009 swine flu pandemic, which boasted 150,000 to 575,000 fatalities before it was over. The investigation indicated that train travel played a key role in the H1N1 outbreak in China as infected passengers transmitted the virus to the crew, who then spread it to other people in the train.


You may think that riding the bus is safer. And perhaps due to the lower volume of daily riders compared to the subway or the Metro Rail, the risk of infection is probably lower. Nonetheless, you have two of the same ingredients: potential carriers and fomites.

What’s the first thing you do when you step foot inside of a bus? You grab the handrail on the door to balance yourself. The same handrail that is touched by virtually every passenger that climbs aboard the bus every single day.

As previously mentioned, evidence suggests that COVID-19 can live for several days on nonporous surfaces like steel. This means that whether you’re gripping the hanging strap or the grab handle, or resting your head on the bus window, you are potentially acquiring pathogens from other passengers.

The fare box itself, with its smooth metallic surface and its frequent contact with hands, cards, and money, could be teeming with infectious material.

If you’re frequently traveling via bus, another thing to consider when thinking about your risk of infection is the overall movement of passengers within the vehicle.

In a study of the 2009 H1N1 influenza transmission during a long-distance bus trip, researchers found out that the transmission rate was relatively low because the passengers were sleeping most of the time. The researchers postulated that the transmission rate could be higher in transport systems where passengers are moving more frequently, therefore increasing person-to-person contact and facilitating the dispersion of infected droplets onto surfaces.

Private Cars

Think you’re safer just because you drive your own car? Think again.

Like other people, you go to public places like grocery stores and schools—touching doorknobs, shopping cart handles, desks, and other high-touch surfaces. When you climb inside your car, you bring pathogens collected from these public hotspots with you and transfer them onto various parts of the car interior, like the steering wheel, seat covers, and gearshift.

As mentioned, your risk of catching the flu when riding a car with someone infected could skyrocket to 99.9%, depending primarily on the car’s ventilation and characteristics.

In fact, newer, more air-tight vehicles, which are better at recirculating air—thus trapping the contagious droplets inside for everyone to inhale—may even put you at greater risk of infection by airborne influenza.

When you climb inside your car, you bring pathogens collected from these public hotspots with you and transfer them onto parts of the car interior, like the steering wheel, seat covers, and gearshift.

However, viruses are not the only things you have to worry about when it comes to cars. One study shows that an average of 700 different kinds of bacteria live within a car’s interior compared to just 80 types on the average public toilet.

Yes, your car could be more hazardous to your health than the grubby toilet at your favorite restaurant.

These car parts collect the most number of bacteria:

  1. 1.Floor mats

  2. 2.Dashboard

  3. 3.Cup holder

  4. 4.Door handles

  5. 5.Change holder

  6. 6.Seats

  7. 7.Steering wheel

  8. 8.Manual window crank handles or power window buttons

  9. 9.Seatbelts

  10. 10.Radio knob

Taxi Cabs & Ride-sharing Services

If you don’t own a car, which is common in certain areas like in New York City, you may decide to forego the crowded subways for something a little more private for your daily commute. But as previously mentioned, whether you ride a taxi, an Uber, or a Lyft, you are still at risk.

Ride-sharing services have been documented to be a possible route for transmission, which is naturally the case if infectious droplets from passengers or drivers fall on door handles, seat belts, or seat covers.

Both drivers and passengers are prone to infection in the confined space of an automotive vehicle. Drivers have been documented to catch the novel coronavirus from passengers—even if said infected passengers are wearing masks. And of course, passengers are also prone to infection, whether from the driver or from fomites in the car that have been contaminated by previous riders.

Like public transit, taxis and ride-share vehicles are now following regular sanitization schedules in an effort to make rides safe for both parties. But this won’t stop the transmission of viruses through airborne pathogens—if you end up riding with an infected individual, it’s difficult to say how safe you will be from their aerosolized respiratory secretions.

The CDC recommends avoiding ride-sharing services (and all public transportation) to prevent the spread of COVID-19, but that hasn’t stopped ride-hailing services like Uber and Lyft from getting more customers amidst the outbreak, as people who are trying to avoid trains and buses turn to them for transportation.

The scramble to seek other modes of transportation also seems to have dramatically increased interest in other ride-sharing solutions, such as bikes.

...a bike’s handlebar grips can host pathogens, which can be transferred to the next user.

Bike-sharing in the country grows more popular every year. In fact, US residents and tourists took 35 million bike-share trips in 2017. And if what’s currently happening in China is any indication, bike-sharing numbers can go through the roof this year as people see the unique advantages of riding a bike—which is that you can get from point A to point B in open air, all while avoiding huge crowds.

Of course, sharing bikes can present the same challenges for public health as sharing cars, buses, and trains with other people, although on a much smaller scale.

Speaking to, Martin J. Blaser, director of the Center for Advanced Biotechnology and Medicine at Rutgers University’s Biomedical and Health Sciences department, says that surface transfer of viruses can also occur when people share bikes.

For instance, a bike’s handlebar grips can host pathogens, which can be transferred to the next user. Aside from viruses, bacteria can also collect on a bike’s seat, which highlights the need for disinfection before and after you hop on a bike.

E-scooters are also a very popular means of transportation in the U.S. You’ll find them scattered all over many major American cities, and they may be even more attractive as a means of transportation (compared to a bike) due to the fact that there’s no seat—you’ll only ever have to touch the handlebars.

So is bike-sharing and/or e-scooter rental the way to go while we’re waiting for the pandemic to ebb away?

The answer? Probably not—but these vehicles are certainly easier to sanitize.


The aviation industry is currently reeling from the impact of the COVID-19 pandemic as governments around the world add more countries to their list of travel bans. But people don’t need to be told not to book flights—in this current climate, nobody is exactly jumping at the idea of being stuck in an airplane for hours with potentially infected passengers onboard.

Thankfully, traveling by plane does not necessarily increase your chances of getting infected, according to the World Health Organization (WHO). Some may cite the “recycled air” within airplanes as a possible factor for greater rates of transmission, but this is a common misconception.

But then again, transmission can happen if a sick passenger coughs or sneezes and there are people seated near them. The Centers for Disease Control and Prevention (CDC) says that the virus can spread from person to person if people are in close contact with one another (within about six feet).

Traveling by plane does not necessarily increase your chances of getting infected.

Since the coronavirus spreads via contagious droplets, the WHO also says that you can catch the illness if you directly touch an infected person or you come into contact with parts of the aircraft cabin and furnishings that an infected person has touched.

Unfortunately, as it turns out, a lot of people can’t sit still during flights. One study shows that most passengers in an airplane leave their seats during a flight, usually to use the restroom or grab items from the overhead bins. These movements can increase close contact between passengers and thus facilitate the transmission of viruses.

How to Protect Yourself from Diseases When You’re Traveling

Needless to say, even as we try our best to practice social distancing and self-quarantines, in many instances, travel can’t be avoided. As of writing, many Americans still have no choice but to continue to go to their workplaces to support themselves and their families, and trips to the grocery store still need to be made to restock supplies.

It’s therefore all the more crucial that everyone learns how to protect themselves when riding any mode of transportation—whether public or private.

Here are some tips to shield yourself against the coronavirus and other illnesses when traveling:

  1. 1.Avoid travel if you’re sick. - If you have any of the usual flu symptoms (coughing, sneezing, runny nose, sore throat, fever), however mild, the best thing you can do for other people is to avoid travel. Seek medical care immediately and share your previous travel history with your healthcare provider.

  2. 2.Wear a face mask if you’re ill and you need to travel. - If you’re forced to travel when you’re sick, wear a face mask. Remember that masks are effective only when used in combination with frequent hand-cleaning with alcohol-based hand sanitizer or soap and water.

  3. 3.Do not use public transportation. - Avoid using any kind of public transportation, taxis, and ride-sharing services. If possible, drive your own vehicle or walk to your destination.

  4. 4.Wash your hands frequently. - Wash your hands for at least 20 seconds using soap and water, especially after blowing your nose, coughing, or sneezing.

  5. 5.Use a travel-sized hand sanitizer. - Grabbing handrails, poles, and other high-touch surfaces usually can’t be avoided when using public transit. If you can’t wash your hands immediately, use an alcohol-based hand sanitizer with at least 60% alcohol, covering the entire surface of both hands and rubbing them together until they are dry.

  1. 6.Avoid touching your face. - A 2015 study that observed 26 individuals to determine face touching frequency found that, on average, a person tends to touch their face at least 23 times per hour. Everyone unconsciously touches their face every day, and while it can be a hard habit to break, it’s a particularly crucial precaution against coronavirus infection.

  2. 7.Avoid close contact with people exhibiting symptoms. - Stay away from people who are showing signs of illness, but make sure to always be polite and calm, so as not to incite panic, fear, and humiliation.

    When traveling, do not touch objects they may have touched. Fomites in public transportation may include handrails, hanging straps, poles, racks, seats, windows, and other smooth surfaces.

  3. 8.Choose seats where you’ll least likely have close contact with other people. -  As the studies we have cited above have shown, the movement of people in public transportation plays a huge role in the transmission of diseases. The more people move, the more they generate close-contact situations that could facilitate the transmission of pathogens.

    In an airplane, for example, researchers have found that passengers in window seats have the lowest likelihood of coming into contact with sick people.

    Only 43% of passengers seated at window seats tend to move around compared to 80% of passengers seated on the aisle. So whether you’re on a plane, bus, train or any mode of public transit, it’s a good decision to choose seats away from other people.

  4. 9.Work from home if you can. - Many companies have now implemented work-at-home protocols for their employees. However, if your employer still has yet to announce such precautionary measures and you believe that your work can be easily completed at home, then it may be time to bring your concerns to their attention.

    Speaking to CEOs and business owners, Dr. Nabarro said during his call with global communications firm Edelman: “Don’t tell [employees] they’re being scaremongers. Don’t tell them that they’re being disloyal, or that they’re working against the interest of the company... You have to respect [their decisions].

Coronavirus or not, travel is a necessity. If we can’t avoid it, then it behooves us to be more responsible and vigilant when we’re riding public transportation or sharing any kind of vehicle with other people. There’s a light at the end of the tunnel in the current pandemic—but we need to do our part to ensure the safety of our families and communities.

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