The winter days when influenza illnesses peak seem faraway as Minnesotans delight in the State Fair and late summer's golden sunlit days. But sadly, the 2019-2020 flu season has already claimed an early victim in California, where a 76-year-old man from San Diego County died in mid-August from complications of this respiratory infection.

While annual flu seasons vary in severity, the contagious virus still reliably sickens millions of people worldwide each year and causes up to 650,000 deaths. Every possible precaution should be taken to guard against it. Unfortunately, it appears that the nation's immigration officials are abdicating their growing role in the public health crusade against the flu — a dereliction of duty that requires immediate remedy.

Members of Congress and medical experts from some of the nation's most prestigious academic centers this month began sounding the alarm about the rising threat of infectious diseases, particularly influenza, in detention centers holding those who have crossed the southern U.S. border. The facilities' "poor conditions" may amplify influenza's spread, said experts from Harvard Medical School and Johns Hopkins University in an Aug. 1 letter to Congress. They strongly urged vaccinating all detained children older than six months against the flu.

But it appears the U.S. Customs and Border Patrol has no plans to vaccinate those in custody. The faulty reasoning was provided in an Aug. 20 statement to CNN: "In general, due to the short-term nature of CBP holding and the complexities of operating vaccination programs, neither CBP nor its medical contractors administer vaccinations to those in our custody."

That excuse looked even flimsier 24 hours later. On Aug. 21, the Trump administration announced plans to hold migrant children and families indefinitely, increasing the risk of influenza and other diseases not only in holding centers but outside them. Detention could last weeks and months instead of hours or days, undercutting the "short-term" rationalization for not vaccinating.

"Given the longer hold times of these kids ... this is a perfect recipe for an influenza outbreak in the kids, which will in turn seed the adult population, both detainees and workers, for a much higher risk of influenza," said Michael Osterholm, a well-known infectious-disease expert with the University of Minnesota's Center for Infectious Disease Research and Policy.

Minnesota is far from the southern U.S. border, but that's little protection against a virus that effortlessly circles the globe each year. As Osterholm points out, an influenza outbreak could sicken detention center employees. They could in turn infect family and friends, allowing this highly contagious pathogen to spread quickly in the region or across the country, particularly in an age in which air travel is common.

It is plainly prudent to wield an inexpensive, readily available tool — the flu vaccine — to prevent outbreaks at detention centers. Doing so is vital to the health of all Americans.

It's also the humane course of action. As the Harvard and Johns Hopkins experts note, three children inside the detention centers have died as a result of influenza since December 2018. Conditions and medical care are in clear need of improvement, and flu vaccinations are a logical place to start. If immigration officials won't reverse course, Congress needs to investigate why and wield its authority to force change.