Last modified on December 25, 2020, at 03:03

Herd immunity

Community immunity is having a large percentage of the population immune to a disease in order to prevent the spread of that disease. Even individuals not immune are offered some protection because the disease has little opportunity to spread within the community. This is also known as herd immunity.[1] The thresholds for herd immunity to protect against various diseases range from 85% to 94% vaccination rates.[2]

On Christmas Eve 2020, The New York Times reported that Dr. Fauci initially underestimated the level of vaccination needed to attain herd immunity from the coronavirus:[3]

In the pandemic’s early days, Dr. Fauci tended to cite the same 60 to 70 percent estimate [of immunity to attain herd immunity as] most experts did. About a month ago, he began saying “70, 75 percent” in television interviews. And last week, in an interview with CNBC News, he said “75, 80, 85 percent” and “75 to 80-plus percent.”

In a telephone interview the next day, Dr. Fauci acknowledged that he had slowly but deliberately been moving the goal posts. He is doing so, he said, partly based on new science, and partly on his gut feeling that the country is finally ready to hear what he really thinks.

Fauci then stated as follows:[3]

Hard as it may be to hear, he said, he believes that it may take close to 90 percent immunity to bring the virus to a halt — almost as much as is needed to stop a measles outbreak.

References

  1. https://www.cdc.gov/vaccines/about/terms/glossary.htm#c
  2. http://www.bt.cdc.gov/agent/smallpox/training/overview/pdf/eradicationhistory.pdf
  3. 3.0 3.1 https://www.nytimes.com/2020/12/24/health/herd-immunity-covid-coronavirus.html (emphasis added).