Along the U.S.-Mexico border between San Diego and Tijuana, researchers are noticing a trend: Syphilis is on the rise in some unhoused communities. The injectable penicillin used to treat the infection is facing a shortage.

Meanwhile, researchers are facing barriers to track the spread of the disease because of restrictions on grants that would allow them to track the spread in Mexico, despite their past studies showing that communities on both sides of the border are epidemiologically intertwined.

Here & Now‘s Scott Tong speaks with Eric Boodman who reported on the increase in cases for STAT.

This segment aired on August 7, 2026.