U.S. travelers and healthcare providers looking for another—and potentially safer—dengue vaccine will have to keep waiting.  | U.S. travelers and healthcare providers looking for another—and potentially safer—dengue vaccine will have to keep waiting. After an ominous delay, Takeda has decided to withdraw the FDA application for its dengue vaccine candidate after the agency raised concerns about data collection.

The issue seems to be how the data was collected in the Phase 3 trial:

Clinical trials of most drugs and vaccines supporting FDA approval are mainly conducted in the U.S. and Europe, where clinical trial protocols are well recognized. The phase 3 TIDES trial used for Qdenga’s application was run in several less well-off, dengue-endemic regions in Latin America and Southeast Asia.

However, it should be noted that Takeda’s drug, Qdenga, is already approved by the EMA in the EU and a couple other agencies. It is just the FDA that is holding things up in the US.