This study analyzed how lockdown strategies and testing capacity influenced COVID-19's Case Fatality Rate (CFR) and viral mutations in seven countries in Europe and North America. After normalizing CFR for each country's PCR testing capability, the study found that strict lockdown policies combined with widespread testing were correlated with a significant decline in the death rate. Genomically, a specific pattern of mutations stabilized by April 2020. A novel mutation in the spike protein was detected exclusively in Sweden, a country that enacted a soft lockdown strategy.