GC: n

S: CDC – http://www.cdc.gov/vaccines/partners/campaigns/index.html (last access: 2 September 2014); HAAD – http://www.haad.ae/HAAD/tabid/1329/Default.aspx (last access: 2 September 2014).

N:
S:

SYN:
S:

CR: herd immunity, immunity, vaccination, vaccination schedule, vaccine.