Sept. 8 (UPI) — The Centers for Disease Control and Prevention said Friday that
CDC: Flu vaccine’s 52% efficacy in Southern Hemisphere could indicate potency in U.S. – UPI.comsaidthe 2023 Southern Hemisphere seasonal influenza vaccine reduced the risk for flu-related hospitalizations by 52% — a possible indicator of its efficacy in the United States this fall and winter.
A 52% efficacy might not meet the public’s perception of an effective vaccine. There may be a disconnect between the public’s expectation and what vaccines deliver. In June 2020, the FDA said the threshold for approving a vaccine was 50% or higher – which implies the flu vaccine is barely effective?
To ensure that a widely deployed COVID-19 vaccine is effective, the primary
Development and Licensure of Vaccines to Prevent COVID-19; Guidance for Industry (fda.gov)
efficacy endpoint point estimate for a placebo-controlled efficacy trial should be at
least 50%, and the statistical success criterion should be that the lower bound of
the appropriately alpha-adjusted confidence interval around the primary efficacy
endpoint point estimate is >30%
The Covid vaccination was initially said to be 95% effective with no safety concerns:
A final analysis of the Phase 3 trial of Pfizer’s coronavirus vaccine shows it was 95% effective in preventing infections, even in older adults, and caused no serious safety concerns, the company said Wednesday.
Pfizer and BioNTech say their coronavirus vaccine was 95% effective with no safety concerns | CNN
Published peer reviewed papers discussed “fully vaccinated against infection”.
Read this – efficacy does not measure what you probably think it measures.
The public’s perception was, if vaccinated, they would not get sick but the CDC estimated in the winter of 2022/23 that 77% of the U.S. population had Covid-19 anyway, which implies the perceived 95% benefit was not a useful statement to the public. (I was 3x vaccinated when I got Covid-19. Every person I know that had Covid-19 was vaccinated 3x to 5x at the time they had Covid-19. None had a serious case of Covid-19, perhaps due to the vaccine.)
After vaccines became available, and “break through infections” hit most everyone, the message was changed to say vaccines were effective at preventing hospitalization or death, which is very different than “preventing infections”.
The CDC has a page on Vaccine Effectiveness but does not say what the Covid vaccine effectiveness was, after the fact, in 2023. They talk about measuring Covid vaccine effectiveness but do not provide a number after years of data collection. A recent published study (post on that coming here in the future) says the Covid vaccine, in retrospect, was just 17% effective in preventing infection.)
The CDC says “flu vaccination reduces the risk of flu illness by between 40% and 60% among the overall population during seasons when most circulating flu viruses are well-matched to those used to make flu vaccines.”
That the public is confused is now blamed on the public – rather than the confusing, misleading or completely untrue statements from experts – and the loss of trust this has caused.
