Data and Code for: Real-world Effectiveness of the Influenza Vaccine in Young Children

The vaccination and doctor's office visits data come from a major health maintenance organization's (HMO) administrative records of doctors' office and clinic visits in California. This sample includes all children between the ages of 2 and 5 inclusive who were enrolled in the HMO at any time between 1 September 2008 and 31 August 2016. In a typical year there were 148,639 children between the ages of 2 and 5 observed in the data.<br>We supplement these data on doctors' office vaccinations and visits with data from the California Department of Health Care Access and Information (HCAI) on emergency department (ED) visits and inpatient stays for children ages 2 to 5 in all of California during the 2008-09 to 2015-16 influenza seasons. Outcomes of interest include visits for specific diagnostic categories. We code a child as having a visit for a specific illness if she visited a doctor, ED, or hospital for that illness between September 1 and August 31 during the relevant influenza season.<br>Since the data are confidential to or owned by the HMO and HCAI, we cannot post them in this archive. We include all code required to reproduce our results, however, and detailed instructions on how we obtained the data.