Three children, aged 2, 6, and 16, had already died of the flu in US custody at the time the offer was made. U.S. Customs and Border Protection have since said that there would be no plans to vaccinate those in their custody.

Newsweek – Trump administration ignored offer of free fly clinic for migrants despite child deaths, physicians say
CNBC – The US won’t provide flu vaccines to migrant families at border detention camps