In January, Fernández chartered a private jet to fly to Brownsville, Texas, and then drove to Los Fresnos, a farming community about 20 minutes away. He waited in a short line at a vaccination site, provided his Mexican passport as proof of identification and received his first dose of the Moderna vaccine. He made the same trip the next month for his second dose.

He estimated that a few thousand residents of his city — which has a population of 120,000 and is home to the headquarters of some of Mexico’s biggest companies — have also traveled north for vaccination.

Not that many would talk about it. Many Mexicans are loath to speak about getting vaccinated abroad, afraid of being labeled elitists.

Juan José Origel, a Mexican television host, was pilloried on social media after he tweeted a photo of himself receiving the shot in Miami, along with the phrase, “how sad that my country didn’t provide me with this security!”