2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77902The approach of N. Gay for estimating the coverage of a multivalent vaccine from antibody prevalence data in certain age cohorts is improved by using computer aided elimination theory of variables. Hereby, Gay's usage of numerical approximation can be replaced by exact formulas which are surprisingly nice, too.8 pages, LaTeX 2eProbabilityCommutative AlgebraQuantitative Biology92C60 (Primary) 92B15, 13P10 (Secondary)text