[1] https://science.thewire.in/health/icmr-defines-interval-for-...
[2] https://www.msn.com/en-us/news/world/covid-reinfection-rare-...
The vaccines effectiveness is (mostly) a factor of how well they prevent the disease COVID-19. It's NOT a direct indication of how well they prevent infection with SARS-CoV-2, since not all infections cause COVID-19 (some are asymptomatic) but it seems to be a reasonably close bound.
Preventing "moderate symptoms", which is enough symptoms that the typical person would stay home from work.
"mild symptoms" means people notice they were more tired than usual, but otherwise didn't feel like it was bad enough to stay home.
"Severe" symptoms, which means people went to a hospital to get treated.
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The 74% and 95% numbers you quoted were against "moderate" symptoms in the Phase 3 trials. IIRC, all vaccines were 100% effective against "hospitalizations" and "death" (severe).
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With that being said, it seems like the asymptomatic effectiveness is something like 60% to 80% (depending on the vaccine). That is: if we constatly do COVID19 tests to check for ASYMPTOMATIC infection, we still see a major reduction in asymptomatic COVID19 in vaccinated individuals.
Very close to 100%, but not quite. In US state of Ohio, 2.8 million vaccinated, 14 hospitalizations from breakthrough cases, all folks with multiple co-morbidities that would have killed them. So, 14/2.8 million = about 99.9995 % over about two months.
Apologies if that was unclear. With only 30,000 people or 40,000 people in the phase 3 trial, its impossible to differentiate between 99.99% and 100%. We can only see how far above 99.99% we've gotten by deploying to the public.
In contrast, there have been anywhere from 1000 to 3000 deaths PER DAY due to COVID19. The only question remaining is: how far back do we go to count COVID19 deaths. Do you want to start in January, or do you want to start in February? Vaccination started in December, maybe we should include December deaths?
The month of February 2021 was well in excess of 50,000 COVID19 deaths. (2000 to 3000 COVID19 deaths per day every day through Feburary). Estimating that to a round number is ~70,000 or so.
74 breakout deaths vs 70,000-ish total deaths puts us in the 99% effective range already. And that's after I've "steelman" chosen lots of numbers not very favorable to my argument.
It seems like a verifiable fact that the vaccines are well in excess of 99% effective against death. How much so (99.9% or 99.99%???) is a mystery to be left for someone who is better at analyzing these statistics.
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The USA is currently experiencing 700 deaths/day due to COVID19. Its not over. As the death count of the unvaccinated population rises day-after-day, it will only make the safety results of the vaccine more and more certain.
>Efficacy is the degree to which a vaccine prevents disease, and possibly also transmission, under ideal and controlled circumstances – comparing a vaccinated group with a placebo group. Effectiveness meanwhile refers to how well it performs in the real world.
https://www.nationalgeographic.com/science/article/yes-vacci...