There are 4 main datasets included 1. The NI titers measured for post-infection ferret anti-sera using Enzyme-Linked Lectin Assay (ELLA) to characterise the N1 NA antigenic drifts of A(H1N1) viruses between 1977-1991. 2. The HI and NI titers measured in individuals aged 5-70 years using HI assay and ELLA, respectively, to observe the immune imprinting patterns across a panel of antigenically distinct HA and NA proteins of A(H1N1) and A(H1N1)pdm09 viruses from 1977-2015. 3. The...