question: BACKGROUND: The COVID-19 pandemic has powerfully shaped people's lives. The current work investigated the emotional and behavioral reactions people experience in response to COVID-19 through their internet searches. We hypothesised that when the prevalence rates of COVID-19 increase, people would experience more fear, which in turn would predict more searches for protective behaviors, health-related knowledge, and panic buying. METHODS: Prevalence rates of COVID-19 in the United States, the United Kingdom, Canada, and Australia were used as predictors. Fear-related emotions, protective behaviors, seeking health-related knowledge, and panic buying were measured using internet search volumes in Google Trends. RESULTS: We found that increased prevalence rates of COVID-19 were associated with more searches for protective behaviors, health knowledge, and panic buying. This pattern was consistent across four countries, the United States, the United Kingdom, Canada, and Australia. Fear-related emotions explained the associations between COVID-19 and the content of their internet searches. CONCLUSIONS: Findings suggest that exposure to COVID-19 prevalence and fear-related emotions may motivate people to search for relevant health-related information so as to protect themselves from the pandemic.