From Inside Edition.

There is a growing mystery surrounding Diane Keaton’s death. How did someone so vibrant succumb to pneumonia at age 79? The iconic actress was at home in Brentwood when a 911 call was made. Inside Edition spoke to New York emergency medicine doctor Tucker Woods. With Keaton’s family’s announcement that she "passed away from pneumonia," older Americans are worried. Doctor Woods recommends anyone over the age of 50 should get the pneumococcal vaccine.