目標：比較新型流感大流行與後大流行期間，台灣民眾有類流感症狀時戴口罩之行為意圖與相關健康信念之差異，並探討不同流行期間民眾健康信念與其戴口罩行為意圖之關係。方法：於2009年及2010年10月，分別依縣市進行分層隨機抽樣，採用電腦輔助電話訪問進行全國調查，訪問年滿15歲之民眾以蒐集健康信念及戴口罩之行為意圖等資訊，分析樣本分別為1,079人及1,067人，電訪完成率分別為68.5%及66.0%。結果：民眾有戴口罩之行為意圖的盛行率，於大流行與後大流行期間分別為95.9%及93.7%。大流行期間，自覺戴口罩非常有效（AOR=4.88）、自覺戴口罩不太困難（AOR=9.23）或一點也不困難（AOR=25.29）及近期無類流感症狀者（AOR=3.55），較傾向戴口罩。反觀後大流行期間，認為疫情有點可能持續擴大（AOR=3.07）、自覺戴口罩有點有效（AOR=5.29）或非常有效（AOR=9.61）及自覺戴口罩不太困難（AOR=10.09）或一點也不困難者（AOR=14.55），較傾向戴口罩。結論：未來針對民眾採取疾病預防行為之衛教計畫，可強調採取該行為之效果，並降低採取該行為可能之障礙。於大流行期間，無需過度強調疫情嚴重度，然於後大流行期間，則需定期提供疫情資訊，使民眾持續採取預防行為。

Objectives: This study investigated and compared intention to wear a face mask during an influenza-like illness (ILI) and associated factors in the general Taiwanese population during the phase-6 influenza A/H1N1 pandemic (pH1N1) and the post-pandemic phase. Methods: Two national surveys using the computer-assisted telephone interview method were conducted in Taiwan during October in 2009 and 2010. Stratified random sampling by region was used to select these two national samples of participants aged 15 years or older. Participants were asked about their intention to wear a face mask during an ILI and their related health beliefs. The final samples consisted of 1,079 and 1,067 participants, resulting in response rates of 68.5% and 66.0%, respectively. Results: Nearly 96% of the participants intended to wear a face mask when having an ILI during the pandemic phase, whereas only 93.7% intended to do so during the post-pandemic phase. Multivariate logistic regression indicated that factors associated with intention to wear a face mask and the strengths of these associations were different during these two phases. During the pandemic phase, participants who considered wearing face masks to be very effective in preventing pH1N1 [adjusted odds ratio (AOR) =4.88], who considered wearing face masks to be not very difficult (AOR=9.23) or not at all difficult (AOR=25.29), and who did not have influenza-like symptoms during the previous month (AOR=3.55) were more inclined toward wearing face masks. By contrast, during the post-pandemic phase, participants who perceived that the pH1N1 outbreak would expand (AOR=3.07), who considered wearing face masks to be effective (AOR=5.29) or very effective (AOR=9.61), and who considered wearing face masks to be not very difficult (AOR=10.09) or not at all difficult (AOR=14.55) were more inclined to wear them. Conclusions: These findings suggest that future health education campaigns should emphasize evidence-based information regarding the effectiveness of the recommended preventive behavior, while perceived barriers should be better understood, addressed, and hence minimized. The seriousness of the disease should not be overplayed during the pandemic phase; however, communication campaigns in the post-pandemic phase should provide regular updates about the outbreak to keep the public alert in order to maintain good preventive health behavior practices.