我國在2009年為防制H1N1疫情蔓延後，推動大規模疫苗接種。但劉小弟接種疫苗後死亡事件，爆發泛綠媒體對疫苗安全強力質疑。衛生部長楊志良隨即抨擊媒體報導將危害國人健康。由於學齡前幼兒接種需打兩劑疫苗，且中間間隔4週，才能提供足夠保護效果。本文因而使用健保資料建構1－6歲幼兒疫苗施打記錄, 著重媒體報導對第二記疫苗（劉小弟事件後）施打比例，來估計媒體報導對疫苗接種的效果。基於泛綠媒體在農業地區的收視率較高，我們採用採差異中差異法模型，透過農、公保家庭小孩估計媒體報導的擴散效果。結果發現媒體報導降低幼兒疫苗如期接種率約為12－22%。DD估計則說明媒體報導具擴散效果。但住院重症率有可能在媒體廣為宣傳下，反而獲得妥善控制。

To prevent the spread of the H1N1 pandemic in 2009, the Taiwanese government launched a large-scale H1N1 vaccination campaign. However, the death of ＂Liu Xiaodi＂ after vaccination triggered a pan-green media questioning of the safety of the vaccine. In response, Minister of Health, Dr. Yang, criticized irresponsible media reports that would endanger Taiwanese heath. Because vaccines for preschool children require two doses, with a four-week gap, to ensure sufficient protection, we thus employed the National Health Insurance dataset to obtain vaccination records for children aged between 1 and 6, and used the second dose vaccination rate (after the Liu Xiaodi incident) to investigate the impact of the media effect. Given that the pan-green media has a higher rating in agriculture counties, we also employ the DD method to compare the second dose rate of children covered by public employee insurance and farmer insurance. Our estimates indicate a large reduction in the second dose vaccination rate, ranging from 12% to 22%. Results of DD estimation also confirms the presence of spillover effects. Finally, the reduction of the vaccination rate significantly decreases, not increases, the hospital admission rate due to H1N1. We suspect that the media coverage unexpectedly lowered the H1N1 infection rate.