Birth cohort
The number of children born in one particular year. This estimate is used to estimate the number of surviving infants taking into account the infant mortality rate.

Bridge Financing
The GAVI Board has agreed to provide so-called ‘bridge-financing’ to those countries which used GAVI resources to introduce the more expensive combination vaccines (DTPHepB, DTPHep-B-Hib) in Phase 1 . The exact mechanics of this support are now being developed but they will entail extending support to those countries which contribute their own resources for purchase of vaccines or co-finance.

Buffer stock
All vaccine awards from GAVI take into account the need for a sufficient buffer stock. Buffer stocks are procured in addition to the estimated quantities needed, to ensure that countries have sufficient vaccines to respond to unplanned events.

Burden of disease
The size of a health problem in an area, measured by cost, mortality, morbidity, or other indicators. Knowledge of the burden of disease can help determine where investment in health should be targeted.