Influenza
Has the ability to cause death b/c it can mutate quickly, producing strains against which humans have no immunity (WHO)
Caused by viruses A&B (WHO)
Disease due to minor changes in influenza viral antigenic proteins (WHO)
Rapid changes in the influenza virus necessitate annual changes in composition of vaccine (WHO)
Vaccines recommended for elderly people and people w/ chronic underlying diseases (WHO)
Two doses are given to young children w/ 1 month intervals between doses (WHO)