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.  Following the announcement, some people online speculated that Mack died due to complications from the COVID-19 vaccine.

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.

Kelley Mack, an actress best known for her work on the horror series “The Walking Dead,” has died at age 33. A representative for Mack confirmed her death to ABC News and said in a statement, “She will be so missed.”