Is the Testing System No Longer Effective for Coronavirus Disease 2019? Elucidating the Policy Change in the United Kingdom.

Various studies have reported the vaccine's efficacy against coronavirus disease 2019; however, there has been little discussion regarding the test frequency since the emergence of the Omicron strain. In this context, the United Kingdom has abolished its free testing program. Our analysis revealed that the decrease in case fatality rate was heavily influenced by vaccination coverage rather than the testing frequency. However, the effectiveness of testing frequency should not be underestimated and therefore needs further validation.