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Fields Changed

Registration

Field Before After
Study Withdrawn No
Intervention Completion Date March 17, 2019
Data Collection Complete Yes
Final Sample Size: Number of Clusters (Unit of Randomization) 34692
Was attrition correlated with treatment status? No
Final Sample Size: Total Number of Observations 47683
Final Sample Size (or Number of Clusters) by Treatment Arms 2450, 2445 and 2429 individuals per treatment arm in the Western region. 19996 and 20362 individuals per treatment arm in the Southern region
Is there a restricted access data set available on request? Yes
Restricted Data Contact [email protected]
Program Files Yes
Program Files URL https://osf.io/qdrc4/ or https://doi.org/10.17605/OSF.IO/QDRC4
Data Collection Completion Date March 17, 2019
Is data available for public use? No
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Post Trial Documents

Field Before After
Description In this study, we found that sending reminders was an effective and scalable intervention strategy to increase vaccination coverage in an older adult population with low vaccination coverage. Communicating the social benefits of vaccinations, in addition to individual benefits, did not enhance vaccination coverage. The effectiveness of letter reminders about the benefits of vaccination to improve influenza vaccination coverage may depend on the prior vaccination history of the population.
Citation Sääksvuori L, Betsch C, Nohynek H, Salo H, Sivelä J, Böhm R (2022) Information nudges for influenza vaccination: Evidence from a large-scale cluster-randomized controlled trial in Finland. PLoS Med 19(2): e1003919. https://doi.org/10.1371/journal.pmed.1003919
Url https://doi.org/10.1371/journal.pmed.1003919
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