A320 captain reported that a wake turbulence encounter resulted in an injury to a flight attendant.

Attributes
ACN	1718921
Time
Date	202001
Local Time Of Day	0601-1200
Place
Locale Reference	ZDV.ARTCC
State Reference	CO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Aircraft 2
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 227 Flight Crew Type 3018
Events
Anomaly	Deviation - Procedural Clearance Inflight Event / Encounter Wake Vortex Encounter

Narrative:

Initial climb out of den. Seat belt sign on; flight attendants up. Climbing through approximately FL280 suspect we encountered wake turbulence from aircraft 10-15 nm ahead and 4;400 feet. Above us (757). Auto flight was engaged. Abrupt 25 degree roll left and increasing. Disconnected autopilot and stabilized the aircraft. Offset 2 nm right of track and reported encounter to ATC. Checked with purser; who reported that everyone was ok. Found out an hour later just prior to top of descent that one flight attendant had fallen during the turbulence encounter and had some side and back pain.

Original NASA ASRS Text

Title: A320 Captain reported that a wake turbulence encounter resulted in an injury to a flight attendant.

Narrative: Initial climb out of DEN. Seat belt sign on; flight attendants up. Climbing through approximately FL280 suspect we encountered wake turbulence from aircraft 10-15 nm ahead and 4;400 feet. above us (757). Auto flight was engaged. Abrupt 25 degree roll left and increasing. Disconnected autopilot and stabilized the aircraft. Offset 2 nm right of track and reported encounter to ATC. Checked with Purser; who reported that everyone was ok. Found out an hour later just prior to top of descent that one flight attendant had fallen during the turbulence encounter and had some side and back pain.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.