In the United States the current injectable influenza vaccination
is distributed by various manufacturers in multi-dose vials
(MDV), single-dose vials (SDV), or pre-filled syringes (PFS). MDV
and PFS are currently the most widely used presentations. PFS cost
slightly more per dose, but offer potential advantages in speed,
disposal, patient safety, and the potential for less contamination
as the syringe is disposed after one use. An MDV usually contains
about 10 doses of vaccine and needs to be perforated with a new
needle and syringe every single time a dose is prepared, which
could increase the risk of contamination. Estimates suggest that
in recent years 25–35% of vaccines administered in the US were
in pre-filled syringes. This is far below the use level in Europe
where an estimated 90% of all vaccines are in prefilled syringes
[1]. The reason for the divergence in US and European vaccine markets
is mostly unknown. One way to understand the penetration
of a product into a market is to reduce the product into its various
attributes and ask potential purchasers to quantify their preferences
for each attribute. We sought to use this approach, known as
the conjoint survey technique, to understand the preferences of US
medical practices for the aspects of vaccine presentation that differ