2023 marks the fourth year that COVID-19 has upended societies. There have been a number of variants since the outbreak of the pandemic, including Alpha, Beta, Delta and Omicron. Nations have gone through different phases of opening, reopening and returning to normalcy. Meanwhile, China has optimized its pandemic policy. For more insights, we talked to Jeffrey Sachs, who served as chair of the COVID-19 Commission for the leading medical journal, The Lancet.