Unable to control the spread of covid-19 pneumonia, the United States had to adopt the strategy of "waiting for change by delaying": the economy did not collapse by releasing water through fiscal and monetary policies, and passively waited for the turnaround of the epidemic. Therefore, the key to judge when to adjust monetary policy is to judge whether the "change" of the epidemic is coming. Since 2021, on the one hand, the number of new cases in the United States has remained high, and the labor force participation rate has been steadily lower than the pre epidemic level; On the other hand, residents' attention to the epidemic has decreased significantly, and the unemployment rate has decreased significantly - this complex situation interferes with the judgment of the Federal Reserve, delays the time point of tightening monetary policy, and exacerbates inflation. From the perspective of vaccination volume and labor force participation rate, the US epidemic may enter a new stage around may 2021 and continue to this day, which prompted the Federal Reserve to finally make up its mind to reduce quantitative easing policy in November. In the future, observing the number of new cases, morbidity and mortality, vaccination and other indicators can help judge whether the United States still needs to "wait for change", so as to judge the direction of monetary policy.
