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 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, who portrayed Addy in Season 9 of The Walking Dead, has died at the age of 33. Her family announced that Mack passed away on Aug. 2 in her hometown of Cincinnati following a diagnosis of glioma of the central nervous system.