1. A solution comprising a purified population of human norovirus VLPs, wherein the norovirus VLPs comprise at least genogroup II VLPs, wherein said solution contains no more than about 80% residual contaminating protein relative to VLP, and wherein said solution is generated by a process comprising:generating or obtaining a cell lysate, culture supernatant, or filtrate containing the norovirus VLPs, wherein said norovirus VLPs comprise at least a first subpopulation with full length VP1 subunit and a second subpopulation with truncated VP1 subunit of the norovirus VLPs;
adjusting the pH of the lysate, supernatant or filtrate to a pH of less than about 5 to generate a pH-adjusted solution;
removing the second subpopulation with truncated VP1 subunit of norovirus VLPs from the pH-adjusted solution using a filtration process to generate a filtered solution, wherein the filtered solution substantially retains the first subpopulation with full length VP1 subunit of norovirus VLPs;
wherein the solution comprises full length VP1 subunit of norovirus VLPs and is substantially free of norovirus VLPs with the truncated VP1 subunit, wherein the solution contains less than about 10% truncated VP1 subunit.