Scott Olson via Getty Images Felipe Gomez Alonzo, an 8-year-old Guatemalan boy, died in U.S. custody at a New Mexico hospital. An autopsy showed he had the flu.

U.S. immigration officials do not plan to vaccinate any migrants in their custody, despite the flu-related deaths of three children this year, according to Customs and Border Protection.

Neither CBP nor its medical contractors administer vaccinations to migrants because of the allegedly short time in which migrants are in U.S. custody and the length of time it takes for the vaccines to be effective, a CBP spokesperson told HuffPost.

CBP has about 200 medical personnel working along the southwestern border to assist at detention centers, according to CBP. In 2018, 423 detainees in centers across the U.S. contracted the flu, according to a Reuters report in March.

The Centers for Disease Control and Prevention recommends vaccinations be given before the end of October for a flu season that typically peaks from December to February. CNBC was the first to report on Tuesday that CBP had decided not to pursue a vaccination program for its detention centers.

Earlier this month, doctors at Harvard, Johns Hopkins and other health care groups wrote a letter to two lawmakers urging Congress to investigate the conditions surrounding the deaths of six children who were detained by CBP after crossing the border.