Fig. 1.

Selection of SARI patients included in influenza vaccine effectiveness analyses, REVELAC-i multicenter case-control study in nine Latin American countries, 2013. ^aBased on the receipt of any dose of influenza vaccine during 2013. Among 734 (76%) children who provided information on the data source used for vaccination status ascertainment, 408 (56%) had vaccination cards reviewed, 317 (43%) had electronic vaccination registers reviewed and 9 (1%) had EPI paper records reviewed. Among older adults, electronic registers were also the main data source used: 948 of 1292 (73%) followed by vaccination cards (338 [26%]) and EPI paper records (6[0.5%]).