Immunological memory and nasopharyngeal carriage in 4-year-old children previously primed and boosted with 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) with or without concomitant prophylactic paracetamo

► PHiD-CV immunisation with prophylactic paracetamol (PP) induced immune memory. ► Minor impact of previous PP on antibody persistence up to 3 years (y) post-booster. ► Nasopharyngeal carriage of vaccine serotypes reduced up to 3 y post-PHiD-CV booster. ► Previous PP seemed to have a limited impact on pneumococcal carriage rates. ► PP-altered lower PHiD-CV immunogenicity is probably of limited clinical relevance.