FDA commissioner Dr. Stephen Hahn, in a July 30, 2020 interview with the Journal of the American Medical Association (JAMA) said the FDA would allow a COVID-19 vaccine to pass emergency authorisation with an minimum 50% efficacy. The reason given the such low threshold was because they ” felt that that was a reasonable floor given the pandemic” and they wanted to “give vaccine manufacturers guidance on how to design their clinical trials”, as Phase 3 trials for Pfizer and Moderna began this week. [1, 2]
Hahn said “It’s possible that the U.S. could end up with a vaccine that, on average, reduces a person’s risk of a Covid-19 infection by just 50%”
In a statement the “FDA would expect that a COVID-19 vaccine would prevent disease or decrease its severity in at least 50% of people who are vaccinated.”
On July 27, 2020 “Dr. Anthony Fauci has said he hopes the vaccine will have an efficacy rate of at least 60%, meaning on average the vaccine reduces a person’s risk of a Covid-19 infection by 60%”…”60% is the standard that you do for the cutoff.” [4]
Experts were quick to point out that even though 50% effectiveness is low, “it could make a difference” just like “the flu vaccine effectiveness can vary widely from year to year, anywhere from 20 percent to 60 percent over the last decade” [3, 5]
Experts said a “vaccine that’s less than 100% effective will still lead to herd immunity”, which can only be achieved with neutralising antibodies!