Plant-based expression systems may represent a promising strategy for oral vaccines against ascariasis. While protection or expression in other systems or routes of immunization does not imply vaccine potential via lettuce, an exploratory Lettuce Vaccine Suitability Index (LVSI) was applied to a dataset on four Ascaris antigens and three biological comparators. For five different criteria (immunologic response, antigen accessibility, plant expression, biological importance, oral delivery compatibility), scores from 0 to 5 were assigned, resulting in a total potential score of 25. Scores were compared across six different weighting scenarios, and underlying publications were reviewed to distinguish facts and assumptions. Baseline LVSI scores were 25 for As16, 23 for As14, 17 for As37 and 15 for As24. The ranking of the Ascaris antigens remained stable across scenarios, in contrast to some comparators. During the literature research, incomplete support was found for several assumptions made in the scoring, particularly concerning proper folding, gastrointestinal stability and transferability between expression systems or routes of immunization. None of the reviewed studies established protection upon lettuce-based immunization with Ascaris antigens. While these first LVSI scores need validation and further refinement before vaccine performance can be predicted, the index offers a transparent tool to structure available information and identify knowledge gaps.