Doctors from Harvard and Johns Hopkins say “poor conditions” at the U.S.-Mexico border are increasing the risk of spreading deadly diseases like the flu. They are urging Congress to conduct a probe into the deaths of six migrant children who were held in detention centers. Autopsy reports show at least three of the children died because of the flu. According to the letter submitted by the doctors, child flu deaths are rare and easily preventable, but poor conditions at the border are amplifying the risks, especially with influenza season around the corner. A Customs and Border Protection spokesperson said people with the flu “are handled as appropriate depending on the specific circumstances,” although he declined to clarify if migrants are vaccinated for the flu when taken into custody. Migrant children are at greater risk for getting sick due to lower immunization rates and inadequate access to healthcare earlier in their lives.