Southwest Airlines passengers on four flights last month got a disturbing letter recently, saying that they could have come into contact with a fellow passenger who has measles. 

And while Southwest seems to have acted as soon as it found out and consulted with the Centers for Disease Control, there’s a special circumstance about Southwest that makes this a potentially bigger deal than it might have been on other airlines.

First, the flights:

  • August 21: Flight #5, Dallas (Love Field) to Houston (Hobby)
  • August 21: Flight #9, Houston (Hobby) to Harlingen
  • August 22: Flight #665, Harlingen to Houston (Hobby)
  • August 22: Flight #44, Houston (Hobby) to Dallas (Love Field)

In an emailed statement, the airline told me that it reached out to every single passenger who was on any of the flights–more than 500 people, going by the average capacity of a Southwest 737. 

And that’s what actually makes this a bigger deal than if it were on another airline. Because one of the defining features of flying on Southwest Airlines is that there is no assigned seating. 

In fact, that feature contributed to it being ranked the #1 carrier for families: if you’re traveling with children under 6, passengers can board in the second group (after “A” but before “B”),  which means it’s almost always pretty easy to make sure that families can sit together.

But in a situation like this one, rare though it might be, that policy works against Southwest. 

Because not only does Southwest almost certainly not know what seats the passenger who has measles was sitting in; it doesn’t have any idea which passengers were sitting in which other seats.

This matters because the CDC would normally mandate that an airline notify everyone who sat within two rows of an infected passenger. But without assigned seating, the airline had to notify literally everyone who took any of the four flights, even though the vast majority of people likely didn’t actually come into contact with the infected passenger.

So, all 500-plus total passengers from those flights are being warned to watch for fevers, colds, and rashes. 

“The rash begins on the face as flat, red spots and spreads down the neck and trunk to the rest of the body,” as The Dallas Morning News summarized, and “other symptoms include a fever over 101 degrees, cough, runny nose and red, watery eyes.”

Since the incubation period runs 21 days, as Dallas County health officials put it in a letter to one passenger: “It is very important for you to watch for symptoms of measles through Sept. 11, 2018.”

That passenger, who shared the letter with a Dallas-area television station, said sure enough, she has a rash.    

“Mostly, like I said, rash appeared on my legs. I did speak to the health department and explained my symptoms, so their advice was to go to the doctor. They didn’t think that it may or may not be measles but they advised me to visit my physician,” the woman, Monica Nicholas, told NBC 5 Investigates.

Here’s Southwest’s statement about the whole thing:

Our Safety & Security groups worked with the CDC to support the agency’s work in reaching our Customers who traveled onboard four intra-Texas flights last week (details below) with a passenger later diagnosed with Measles. We’ve shared awareness of the situation and protocols with our Employees who also were onboard these aircraft. Our entire fleet is subject to rigorous and regular cleaning programs and every aircraft utilizes hospital-quality HEPA filtration that improves overall quality of the air in the passenger cabin.

Written by