Seasonal influenza vaccine effectiveness study in older adults during three influenza seasons (2015-2018) in Lithuania
Background: Due to lack of knowledge about seasonal influenza vaccine effectiveness (SIVE) against laboratory-confirmed influenza in patients aged ≥65 years a study to measure SIVE in patients admitted to hospital due to severe acute respiratory infection (SARI) in Lithuania during the 2015-2018 was conducted.Materials/methods: A test-negative case-control study was performed between 2015-2016 and