Huge impact of assumptions on indirect effects on the cost-effectiveness of routine infant vaccination with 7-valent conjugate vaccine (Prevnar).

Several recently published European cost-effectiveness studies on the 7-valent pneumococcal conjugate vaccine (PCV-7: Prevnar((R))) have included net-indirect vaccine benefits for non-vaccine protected groups into their studies, which might be too optimistic an approach given recent data. Net-indirect effects result from herd protection minus serotype replacement effects. In this study we analyze the impact of net-indirect effects in non-vaccine protected groups of 5 years of age and older with updated assumptions regarding epidemiologic data and health care unit costs. Without net-indirect benefits for non-vaccine protected groups included the cost-effectiveness ratio is estimated at euro72,360 per QALY. In order to obtain cost-effectiveness ratios below the threshold of euro50,000 per QALY - which is in the middle of the range that is often referred to in the Netherlands - the net-indirect protective effect should at least be 16% of which has been observed in the USA after the introduction of PCV-7.