In the Before Times, I would often board a plane for vacations and quick weekend trips to visit friends — and I would inevitably get sick immediately upon my return home. Whether it was a 10-hour flight back from Italy or a two-hour flight after a beach weekend in North Carolina, that trip would soon be followed by a scratchy throat and achy chills that would later transform into a stuffy nose. It felt like it was unavoidable — and it became all the more pronounced when, during the pandemic, I didn’t take a plane anywhere and caught considerably fewer colds in the process.

This phenomenon doesn’t just hit me. “It does come up that people will notice after flights that they do come down with something days later,” Dr. Paul O’Rourke, M.D., M.P.H., the associate program director at Johns Hopkins Bayview Internal Medicine Residency Program, told Apartment Therapy. 

Whether your first vacation in a while is in the next few months or next year, it’s good to get down to the culprits of these flight-induced illnesses to better protect yourself as vaccinated people begin to travel again — especially because the coronavirus is still a very real thing. I spoke to experts about why flying, in particular, can make you feel so crummy and what you can do to prevent these illnesses as you embark on trips in the near future. 

Culprit #1: You’re Not Drinking Enough Water

Whenever I fly, I tend to avoid drinking water, even though experts recommend staying plenty hydrated. I feel bad about asking the person next to me to stand up so I can go to the bathroom — yet I still almost always pick the window seat. But, according to Dr. O’Rourke, that could be the very reason I feel so awful after flying. 

“In airplanes, as they ascend, the cabin gets to be very low humidity, low water moisture in the air,” he says. “That causes our nose and throats to really dry up.”

By not properly hydrating, the dryness can predispose you to get viral infections with potential having breaks in your throat or reduce mucus lining that usually helps protect you from bacteria, Dr. O’Rourke explains. So forcing myself to bother the stranger might be worth it if it reduces illness. 

Additionally, if you’re drinking alcohol on a plane you should be extra cautious to make sure you’re hydrated while up in the air.

Culprit 2: Germs Are Lurking Everywhere

Dr. O’Rourke believes people are just as likely to catch germs from the air in an airplane as they are in any other enclosed space thanks to HEPA filters and air circulating, but people can still catch germs from hand-to-mouth contact, which may occur if you’re snacking on the plane and don’t have proper cutlery. Wearing a mask on the plane — yes, even after you’re vaccinated against COVID-19 — can help minimize this from happening.

Dr. Dana Hawkinson, MD, an infectious disease physician and the medical director of Infection Prevention and Control at The University of Kansas Medical Center, notes that even though you may be vaccinated for the coronavirus, you’re still susceptible to other respiratory viruses and other infections. That’s why it’s especially important while traveling to maintain proper hand hygiene and other non-pharmaceutical interventions like wearing a mask and distancing as much as possible.

While airlines have been extra cautious about sanitizing the planes in between flights since the pandemic, there are still high-traffic areas that you want to be extra cautious about, namely the tray table and the seat pouch. It’s essential to give extra attention to these areas sanitation-wise and if you place anything in the pouch in front of you, wipe it down before touching your face.

Culprit #3: Your Guard Is Down in General

There’s no way around it: Traveling is stressful. You may be more worried about trying to find your flight gate before your boarding time than you are about refilling your reusable water bottle. The same goes for sanitizing your hands or wiping down your seat.

“You’re going to be traveling so you’re probably not going to be doing your best practices for hygiene,” Dr. Hawkinson says. The same goes for vacation travel, in general. And you’re likely not doing your best to get adequate rest or maintain healthy habits, which could impact your immune system during the flight home.

Simply forming a mental checklist of drinking water, masking up, sanitizing, and not touching your eyes or nose can go a long way in not feeling horrible a few days after you return home. And while it’s only natural to indulge on vacation and take things a little easier, be sure to check in with your body and how it feels throughout your trip.

How should you know if you need to get a COVID test?

According to Dr. Hawkinson, most respiratory infections don’t start to develop symptoms until about three to seven days after you’re exposed, which includes common colds and, yes, COVID-19. Even if you’re vaccinated for the coronavirus, but still feel gross after flying home, it might be worthwhile to get a COVID test just to be safe.

Currently, the Centers for Disease Control and Prevention (CDC) recommends that anyone with any symptoms of COVID-19 get tested, regardless of vaccination status. So if you’re experiencing cough, fever, chills, or loss of taste, it’s always a good idea to check to make sure those potentially unvaccinated around you don’t get sick.

Dr. Hawkinson added that those who are vaccinated won’t feel the effects of COVID-19 as deeply. “If you are fully vaccinated with whatever vaccine, you’re going to have less risk of having those symptoms overall and you’re going to have less risk of having a prolonged duration of active virus or active viral replication,” he says. Even so, he suggests still getting a COVID test because you may come into contact with unvaccinated people and put them at risk. Quarantine properly until you get your test results, maintain a safe distance from others, and follow other hygiene protocols like mask-wearing and washing your hands .

“At this time, if you get sick, I would encourage people to stay home and consider getting a rapid test just to confirm that you can be safe going around other people,” Dr. O’Rourke adds.