7 ms·

This is not a surprise. It takes 2 weeks before the first dose is effective, and 3 weeks after the first dose, a second dose is required to boost the efficacy.

This is not a surprise. It takes 2 weeks before the first dose is effective, and 3 weeks after the first dose, a second dose is required to boost the efficacy. It’s 2 weeks after the second dose that the vaccine takes about 95% efficacy.

drKarl 6y ago
Also, it's 95% effective, so it's expected to have a 5% failure rate
- DanBC 6y ago
  What does "95% efficiency" actually mean?
  - _Microft 6y ago
    The third phase trial was double-blinded and when they unblinded it, it turned out that of all the people (170 persons) who got infected, only 5% (8 persons) were in the group of those who got the real vaccine. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine https://www.pfizer.com/news/press-release/press-release-deta...
    - bosie 6y ago
      that's not what your links says nor what pfizer tested/claims? pfizer didn't test for infections, they tested for symptoms. Pfizer doesn't know if the infection rate is changed (could be more, could be less, who knows)
      - _Microft 6y ago
        I phrased that incorrectly indeed.
  - rualca 6y ago
    It means that it's double blind study showed that only 5% of those who took the vaccine contracted and developed covid19 symptoms when compared with the placebo group. https://www.nytimes.com/2020/12/13/learning/what-does-95-effective-mean-teaching-the-math-of-vaccine-efficacy.html https://www.nytimes.com/2020/12/13/learning/what-does-95-eff...
    - deleted 6y ago
      [deleted]
    - layer8 6y ago
      “5% of those who took the vaccine developed covid19 symptoms” is somewhat misleading. Rather, for a vaccine and a placebo group of the same size, the number of people in the vaccine group who developed covid19 symptoms (only 0.037% of that group) was 5% the number of people in the placebo group who developed covid19 symptoms (0.74% of that group).
      - rualca 6y ago
        > “5% of those who took the vaccine developed covid19 symptoms” is somewhat misleading. You misquoted me for some reason. I explicitly stated that "only 5% of those who took the vaccine contracted and developed covid19 symptoms when compared with the placebo group." This is a direct quote of what I actually said, which bears no resemblance to your comment.
  - vinay_ys 6y ago
    Vaccines have "efficacy" (lab conditions) and "effectiveness" (real-world conditions) as two different metrics. Vaccine efficacy- % reduction in disease incidence in a vaccinated group compared to an unvaccinated group under optimal conditions (example: Randomized Control Trial). Vaccine effectiveness- ability of vaccine to prevent outcomes of interest in the “real world”. This short interview with a virologist is interesting for contrasting between different vaccines https://www.youtube.com/watch?v=d2KVKn0BvlM https://www.youtube.com/watch?v=d2KVKn0BvlM
    - blackrock 6y ago
      Geez, they need a more clear term. It’s no wonder, nobody understands what the hell they’re talking about. They should use: theoretical vs. real world, instead.
pmoriarty 6y ago
Not only that, but she could have been infected before she was vaccinated.

drKarl 6y ago

Also, it's 95% effective, so it's expected to have a 5% failure rate

DanBC 6y ago
What does "95% efficiency" actually mean?
- _Microft 6y ago
  The third phase trial was double-blinded and when they unblinded it, it turned out that of all the people (170 persons) who got infected, only 5% (8 persons) were in the group of those who got the real vaccine. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-conclude-phase-3-study-covid-19-vaccine https://www.pfizer.com/news/press-release/press-release-deta...
  - bosie 6y ago
    that's not what your links says nor what pfizer tested/claims? pfizer didn't test for infections, they tested for symptoms. Pfizer doesn't know if the infection rate is changed (could be more, could be less, who knows)
    - _Microft 6y ago
      I phrased that incorrectly indeed.
- rualca 6y ago
  It means that it's double blind study showed that only 5% of those who took the vaccine contracted and developed covid19 symptoms when compared with the placebo group. https://www.nytimes.com/2020/12/13/learning/what-does-95-effective-mean-teaching-the-math-of-vaccine-efficacy.html https://www.nytimes.com/2020/12/13/learning/what-does-95-eff...
  - deleted 6y ago
    [deleted]
  - layer8 6y ago
    “5% of those who took the vaccine developed covid19 symptoms” is somewhat misleading. Rather, for a vaccine and a placebo group of the same size, the number of people in the vaccine group who developed covid19 symptoms (only 0.037% of that group) was 5% the number of people in the placebo group who developed covid19 symptoms (0.74% of that group).
    - rualca 6y ago
      > “5% of those who took the vaccine developed covid19 symptoms” is somewhat misleading. You misquoted me for some reason. I explicitly stated that "only 5% of those who took the vaccine contracted and developed covid19 symptoms when compared with the placebo group." This is a direct quote of what I actually said, which bears no resemblance to your comment.
- vinay_ys 6y ago
  Vaccines have "efficacy" (lab conditions) and "effectiveness" (real-world conditions) as two different metrics. Vaccine efficacy- % reduction in disease incidence in a vaccinated group compared to an unvaccinated group under optimal conditions (example: Randomized Control Trial). Vaccine effectiveness- ability of vaccine to prevent outcomes of interest in the “real world”. This short interview with a virologist is interesting for contrasting between different vaccines https://www.youtube.com/watch?v=d2KVKn0BvlM https://www.youtube.com/watch?v=d2KVKn0BvlM
  - blackrock 6y ago
    Geez, they need a more clear term. It’s no wonder, nobody understands what the hell they’re talking about. They should use: theoretical vs. real world, instead.

pmoriarty 6y ago

Not only that, but she could have been infected before she was vaccinated.