美媒：美国为何抗疫失败？无能、阶级暴力、欺骗和谎言(8)

The effectiveness of herd immunization remains to be seen. When Trump was the U.S. President, he supported White House senior medical advisor Scott Atlas who said that if enough people were vaccinated (or infected with COVID), the virus would have nowhere to spread and die out naturally.18 For the same reason, Biden also focuses on vaccination, arguing that if vaccination rates reach 70% or more, masks can be fully abandoned and social activities resumed.19 But historically, effective herd immunization (e.g., measles) has three necessary conditions: a stable, non-mutating virus, a very effective vaccine, and high vaccination rates. And none of these three conditions existed at the beginning of the COVID pandemic.
In more than two years, COVID-19 has mutated into at least six major variants; vaccines effective against the Delta variant have become limited against Omicron;20 and vaccine efficacy decreases by 20 to 30 percentage points after about six months.21 There is also no evidence that patients infected with COVID-19 are automatically immune (like smallpox or mumps), and the number of reinfections with coronavirus has been rising sharply since the Omicron variant was discovered.22 From the beginning, Chinese central health officials have maintained the right scientific attitude and insisted that no compromise be made until there is sufficient evidence.