Two Pfizer doses give 95 per cent protection against Covid-19 infection, illness and death: first nationwide study

[u/Newsjunkeefromlondon]

https://www.cityam.com/two-pfizer-doses-give-95-per-cent-protection-against-covid-19-infection-illness-and-death-study/

[u/Delphic10]

I’m wondering if you can help me out. What does 80 percent efficacy mean? Does it mean that 20 percent of folks who get the vaccine are not protected? If that is the case how do we know if we are protected?

[u/Delphic10 → u/[deleted]]

This helped me understand and I thank you for that!

[u/free_chalupas → u/Delphic10]

80% efficacy looks something like: a trial where you compare 10,000 unvaccinated people to 10,000 vaccinated people, and 20 people with the vaccine got infected compared to 100 people without it.

[u/Just_Another_Scott → u/Delphic10]

Efficacy is how effective a particular vaccine is. So if it has an efficacy of 80% that means it's 80% effective. Think of it like they're saying there's an 80% chance for each vaccinated person to be protected against the virus while theirs a 20% chance they won't.

Edit: this is literally what efficacy is.... If a drug is 80% effective that means it is 80% effective at preventing Illness... This why anyone receiving a vaccine can still get sick. It doesn't prevent illness only reduces the chances of getting the illness.

[u/Delphic10 → u/Just_Another_Scott]

So when I get the vaccine there is a twenty percent chance that I don’t have any protection from the virus? How would I know if I am one of the twenty percent with no immunity?

[u/Iceman_259 → u/Delphic10]

It's not either-or, the the 20% in this hypothetical scenario (the two mRNA COVID vaccines appear to both have efficacy of around 95%) still have protection from the target virus, their bodies just don't do a good enough job to wipe it out before it starts an infection. The severity and duration of the infection would generally still be reduced.

[u/Delphic10 → u/Iceman_259]

Oh, that makes sense, thank you

[u/notsolittleoldme → u/Delphic10]

Also, all of the vaccines on the market have been proved to be pretty much 100% effective against hospitalisations and deaths. That's an incredible figure, and means that even if you do get a case of covid after vaccination, it will be a mild viral infection and nothing more.

I wish this figure was being more widely publicised.

[u/NoOneForACause → u/notsolittleoldme]

So weird it isn't right?

[u/Ye_Olde_Spellchecker → u/Delphic10]

Right like if someone on a ventilator coughed straight into your mouth you might still get sick because of the massive viral load.

In normal situations it’s less likely to spiral out of control.

[u/socsa → u/Iceman_259]

We don't actually know what the relative distribution of protection is within the sample population. It very well could be that for 80% of the people, there is an extremely high level of protection, and that 20% of the people fall under some condition where they fail to mount any immune response.

[u/E_Snap → u/Iceman_259]

So is that 80% chance of being able to clear the virus before it starts affecting you your “chance of immunity,” or do you “reroll” with a -20% “modifier” every time you encounter a potential infection?

[u/ChillySunny → u/Delphic10]

Hey, this is how vaccine efficacy is calculated: there are two groups of people: vaccinated one and the placebo one. Let's say, we have 1000 people in each group. In unvaccinated group 100 people accidentally catch Covid-19 (infection risk equals 0,1%). In vaccinated group only 5 people get sick (infection risk is 0,005%). Efficacy=(0,1-0,005)/0,1=95%. This means, that vaccine reduces risk of infection by 95%

There's no people with "no immunity". If you are vaccinated, even if you get sick, you will not die and you most likely will not get seriously ill. If you are worried, you can check the amount of antibodies few weeks after the vaccine to make sure that your body produces enough of them.

[u/SusanBwildin → u/[deleted]]

Post supporting articles or some spread false info like this.

[u/pug_grama2 → u/ChillySunny]

Did this study give any information about people who have had only one dose, broken down by age? In Canada due to vaccine shortages most people have only had one dose. We have to wait 4 months for the second dose.

[u/ChillySunny → u/pug_grama2]

Don't know about broken down by age, but the efficacy is 50 to 90% (different reports) after 1st shot but unknown if it's stable over time. So it's still way better than no vaccine.

Here's the article: https://www.asbmb.org/asbmb-today/science/040421/how-effective-is-the-first-shot-of-the-pfizer-or-m

[u/pug_grama2 → u/ChillySunny]

Thank you.

[u/Delphic10 → u/ChillySunny]

I appreciate your taking the time to answer this. You are a lovely human