Mayen-Herrera E1, Buesch Katharina2, Cortina D3 OBJECTIVES: To determine the incremental cost-effectiveness ratio (ICER) of the use of palivizumab as prophylaxis for the reduction of complications associated with respiratory syncytial virus (RSV) in pre-term patients <29 weeks of gestational age (WGA) under the Mexican public health sector perspective. METHODS: A cost-utility model was developed based on a decision tree that evaluated both scenarios of prophylaxis and no-prophylaxis. Epidemiological and cost data were obtained from different Mexican sources such as the Mexican Institute of Social Security (IMSS) by analysing birth rates. Clinical effectiveness was obtained from the international literature (Cardiac Synagis Study Group, The IMpact-RSV Study Group MEDI-493 Study Group). Prophylaxis therapy consisted of 5 applications of palivizumab during the winter season in Mexico. The dose scheme considered was 15 mg/kg. The effectiveness outcomes were quality adjusted life years (QALYs). Since the study was conducted under the public health perspective, only direct medical costs associated with the RSV treatment were evaluated (hospitalization, emergency room, drugs, and prophylaxis). For resource utilisation purposes, an expert panel of paediatricians with experience in RSV infection was convened. Drug and medical attention costs were discounted by using a 3% discount rate and are reported in local currency. Acceptability curves of the probability of palivizumab to be cost effective were calculated. The threshold included in the study for cost-effectiveness comparisons, is the proposed by the World Health Organisation (3 times the gross domestic product per capita). RESULTS: The ICER per QALY for the study group was MXN $219,150. The acceptability curves showed a 75% probability of palivizumab to be cost effective when employing a 3 times GDP threshold. CONCLUSIONS: The use of palivizumab represents a cost-effective alternative for the prophylaxis of complications associated with RSV infection, under the public health perspective in Mexico for patients <29 WGA.