Cost efficiency is about doing things at the lowest possible cost, minimizing waste and maximising productivity and operating as near as possible to the bottom end of the marginal Price curve.

Cost effectiveness is about doing things that work- measles immunisation provides 95% protection against measles when given to the right person at the right time with a vaccine of demonstrable power to trigger an antibody response. It is Cost Effectiveness when Measles works, not just in the laboratory or clinical trial - that is Cost Efficacy - but daily, weekly, monthly in the clinics and hospitals around the world despite problems of record keeping, cold chain, professional skill, parental trust ….

and in consequence Measles outbreaks are reduced and fewer CHILDREN DIE. Thus there is a Cost and a Benefit Equation

The Cost is the Cost of the Vaccine manufacture, test, purchase, transport

plus the Cost of the Staff-training, salary plus the Costs of Administration - Clinics, staff, needles, syringes, record keeping.

The Benefit is the Number of Children who are immunised and the implication for Morbidity and Mortality from Measles in that same population. This may be estimated in financial terms and thus Cost and Benefit compared in the same unit of money.