Tell Me Where to Get My Flu Shot - Effects of Information in Prevention

From a public health perspective, the flu vaccination rate is viewed as too low in many countries. While up until recently, only physicians were allowed to vaccinate in Switzerland, some pharmacies received the license to vaccinate during the course of the year 2016. Public health authorities hope to increase the vaccination rate as there is generally no need for an appointment in a pharmacy. This setting allows us to test whether the vaccination rate can be increased by a letter informing consumers about the access to prevention care as well as whether consumers can be nudged to get their flu shot in a recommended pharmacy.

We use a randomized control trial where a large Swiss health insurer sent letters to 22'000 of its customers (between 50 and 75 years of age). The letter included information about the new possibility to get a flu shot in a pharmacy, a pledge to bear the costs and an indication of the nearest pharmacy which had the license to vaccinate. The letter increased immunization rates by 2.7%-points (17.9%) with significant heterogeneity in background variables as well as with respect to the distance to the pharmacy. We find some provider substitution effects from physicians to pharmacists. Yet, the majority of the increase in the vaccination rate is driven by additional vaccinations in the pharmacies. More than half of the customers visited the recommended pharmacy even if a closer one had been available. Currently, we do not find any significant effects of the flu shot on covered health care expenditures nor on the number of doctor visits.

Information letters proofed to be an effective tool to increase the use of prevention care as well as to guide consumers to specific health care providers. The new possibility to vaccinate in a pharmacy increased the take-up rate of the vaccination. However, the effectiveness of the flu shot remains currently doubtful.