Intensive care admissions and associated severity of influenza B versus A during influenza B-vaccine mismatched seasons

Patients admitted to hospital with influenza B and A in Jerusalem, Israel, 2015-2016/2017-2018, demonstrated similar rates of ICU admission and associated disease severity. Most (63%) influenza B-ICU patients received influenza B-mismatched trivalent vaccine. These findings call into question the equivalence of trivalent and quadrivalent vaccines in preventing severe influenza B.