Kelley Mack, an actor who starred in "The Walking Dead," died due to complications from the COVID-19 vaccine. Actor Kelley Mack, who was best known for playing Addy on the TV show "The Walking Dead," died at age 33 on Aug. 2, 2025, her sister announced in an Instagram post .

Kelley Mack’s death at 33 is putting glioma under the spotlight. After news broke that The Walking Dead and 9-1-1 star had died on Saturday, August 2, fans were reminded that the actress was recently diagnosed with glioma of the central nervous system.

Kelley Mack, an actress best known for her role as Addy on the television series The Walking Dead, died last weekend, her family announced on Tuesday. She was 33. Mack was diagnosed with glioma, an aggressive tumor that affects the central nervous system, last year.