Can chickenpox kill anybody without vaccine?

Chickenpox can be fatal, especially for those who are not vaccinated. People who are immunocompromised, such as those with HIV/AIDS, cancer, or undergoing chemotherapy, are at an increased risk of developing complications from chickenpox, such as pneumonia, encephalitis, and death. Infants and adults over the age of 50 are also at an increased risk of complications from chickenpox. While the chickenpox vaccine is not 100% effective, it is highly effective in preventing chickenpox and its complications, including death.