Influenza vaccine and work productivity:evidence from food delivery driver

This research aims at studying the impact of financial incentives on the take-up willingness of influenza vaccine. Moreover, the researchers examine the relationship between influenza vaccine and health outcomes. If health is improved after taking the vaccine, do we observe an increase in the worker productivity as well. Meanwhile, the researchers quantify the peer influence in the willingness to take the vaccination. Our first intervention includes a financial incentive on vaccine uptake by providing influenza vaccine subsidies covering 50% and 100% of the average vaccine cost, using a control group that receives no subsidy. Our second intevention is the information diffusion where we randomize participants into peer-on and peer-off groups where the peer-on group receives information of the vaccination decision of their vaccinated peers every two days (SMS messages).

2025-10-15

2026-03-15

1. take up the influenza vaccination or not 2.The self-reported health (mental, physical health) 3. worker productivity of food delivery drivers (volumes of order, duration, reviews)

We conducted a randomized controlled trial to examine the impact of influenza vaccination on vaccine uptake and worker productivity among food delivery drivers in China. In addition, we quantify the peer influence associated with vaccination behavior. Approximately 750 drivers were recruited for the study. After collecting baseline demographic and socioeconomic information—including gender, age, education, marital status, wage, job experience, working hours, health status, medical history, health behavior, and health insurance coverage—participants were randomly assigned to one of three treatment groups or a control group across two rounds of vaccination.

The field experiment consisted of four groups in total: one control group and three treatment groups. Participants in the control group received no financial incentive for vaccination and no information about the vaccination status of their peers. The first treatment group received a low financial incentive, offering participants a 50% discount on the average vaccination cost, without any group information. The second treatment group received a high financial incentive, offering a 100% subsidy of the average vaccine cost. The third treatment group received peer information only—participants were informed of other drivers’ vaccination outcomes but received no financial incentive. Comparing vaccination uptake between the peer-information group and the control group allows us to identify the role of social influence in vaccination decisions. Random assignment ensures that any observed differences in outcomes can be attributed to the vaccination incentives rather than to pre-existing individual characteristics.

Worker productivity was tracked throughout the study period using four key performance indicators: (1) order volume (total number of completed deliveries), (2) on-time delivery rate (percentage of orders delivered as scheduled), (3) average delivery duration, and (4) number of positive customer reviews. By comparing productivity outcomes across the four groups, we evaluate whether vaccination incentives affect not only vaccine uptake but also subsequent work performance.

Not available

Creating treatment and control groups by computer software STATA for randomization.

Individual randomization

Yes

750 food delivery drivers

4800

200 in high and low financial incentive treatment, 200 in control groups. The remaining 150 in peer-on group.
Around 750 clusters.

Individual clustering