The initial proposal included provision for an interview to collect information on potential risk factors for carriage, collection of a pharyngeal swab from each study participant, and 8 swabs from household contacts of index carriers over a six-month period. It included provision for the collection of one 5 ml blood sample during the initial cross-sectional survey from 800 subjects aged 6 months or older for baseline serological assays, and for collection of a further 5 ml post-vaccination sample. It also included provision for collection of a 5 ml blood sample from all subjects over the age of 6 months during the first visit of the household follow up study to determine concentrations that protect against acquisition of carriage.