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Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

ox.ac.uk

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Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#61

Post by mrtksn »

krzyk wrote: post #57

How that compares to the announcement from https://www.ema.europa.eu/en/news/ema-recommends-covid-19-va... where they state the the efficacy is 59.5%? Is it a different dose or different timeline?

“The initial data from Astra and Oxford last month appeared positive but raised concern over how much protection the shot would offer after the trials produced two different results from two dosing regimens. The partners said their vaccine was 90% effective when a half-dose was given before a full-dose booster, and that two full doses showed an efficacy of 62%.”

https://www.bloomberg.com/news/articles/2020-12-08/astra-vac...

Turks also find that the Sinovac vaccine is %91 effective when others reported less.

I guess it depends on the variant, on what do you understand by “protected” or on how much you want it to work.

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#62

Post by hutzlibu »

akiselev wrote: post #52
hutzlibu wrote: post #38

Earlier quoted context omitted.

It is so frustrating, trying to figure out at least a bit of whats going on and understanding some numbers, but apparently I cannot do this, without having to dive into papers, too? There is so much confusion and missinformation flying around, when even here on HN there is discussion about the meaning of basic numbers. (but please carry on discussing it)

To be clear, this isn't some settled math like basic algebra or science like Newtonian physics - this is cutting edge stuff at the intersection of medicine, public health, and biotechnology. Experts disagree about the nuances of measuring the efficacy of drugs, vaccines, and therapeutics so throw in the glaring ethical concerns into the mix and you have a recipe for a complex field. It's rare (unheard of?) to find a…

I get it, that I won't really get it, without studying it. But it would be nice, to know what important numbers roughly mean, without that amount of work.

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#63

Post by orra »

lbeltrame wrote: post #9
dhbradshaw wrote: post #4

What exactly does "percent protection" mean in these announcements? Can we use the definition to derive a percent protection associated with having been through the virus? Is there a percent protection associated with your age / gender / race profile? It feels like the number doesn't mean much without having a similar number for the null cases.

It is a reduction of the risk of symptomatic disease by 76% once vaccinated. But more importantly, there were no hospitalizations or deaths in the vaccinated people. This is a point the media often overlooks.

Indeed. These are some of the best vaccines ever invented[1].

Look at the two charts[2] in this paper from the UK's JCVI. They show the number of severe incidents (severe COVID or death). The linear or exponential growth curves are for people on the placebos. The almost flat lines are for people on the Pfizer-BioNTech and the Oxford-AstraZeneca vaccines, respectively.

Oh, after just the initial dose, not the booster!

[1] https://www.nytimes.com/2021/01/18/briefing/donald-trump-par...

[2] https://www.cas.mhra.gov.uk/ViewandAcknowledgment/ViewAttach...

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#64

Post by throwaway2245 »

renewiltord wrote: post #60
throwaway2245 wrote: post #47

Earlier quoted context omitted.

A randomly controlled challenge trial would involve deliberately infecting scores of unvaccinated people, putting them at risk, along with anyone involved in the procedure and anyone they come into contact. It would mean handling live virus, which requires a Biosafety Level 3 facilities. And, it's not going to get your vaccine approved any quicker.

See, this is a classic example. You need BSL3 facilities if you want to have a hundred people have it. But the alternative is 27 million people getting it in planes, boats, and buses - none of which are BSL3. That part is okay. Quite the example of the asymmetry. If you engage with the problem you have to operate absolutely perfectly. Way better not to engage with it and kill a few hundred thousand people. After all,…

> You need BSL3 facilities if you want to have a hundred people have it. But the alternative is 27 million people getting it in planes, boats, and buses - none of which are BSL3.

Those things are not true alternatives.

I said "it's not going to get your vaccine approved any quicker" in the hope that you would understand: vaccines have reached the point of global distribution without doing the additional deliberate harm of intentionally infecting people.

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#65

Post by thehappypm »

ummonk wrote: post #48

The case for a one-dose first strategy gets stronger and stronger, but due to slavish proceduralism, the FDA wouldn’t consider it.

There is 0 data that any of the vaccines approved by the FDA are efficacious with a single dose. There is 0 data to support that a delayed dose is efficacious. The FDA is making a very, very valid choice so far.

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#66

Post by iggldiggl »

Eric_WVGG wrote: post #53
StavrosK wrote: post #51

Earlier quoted context omitted.

> The author explains that the efficacy number is derived from the the number of the number of people in the control/placebo group infected divided by the total number of infections in the study. Wouldn't that make a vaccine that does nothing 50% effective, instead of 0% effective (which is what one would expect)?

Well, let's see… say you had 2000 participants in the trial, 1000 with a junk vaccine, and 1000 with placebos. Furthermore, let's say you had 200 infections, split equally between the junk and the placebo. So yeah, 100 / 200 = 50% effective. A coin toss, which is to say, no better or worse than not getting the vaccine. Again, this isn't measuring "what one would expect" (how many vaccinated people, exposed to the vir…

No, 50 % means the infection rate (or whatever you're actually measuring) in the vaccine group is half that of the control group. In your example the infection rate are exactly the same, giving an efficacy of 0 % (± whatever confidence interval the size of your trial and placebo groups gives you). See e.g. https://blogs.sciencemag.org/pipeline/archives/2020/09/21/th...

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#67

Post by [deleted] »

Eric_WVGG wrote: post #23
reportingsjr wrote: post #18

Earlier quoted context omitted.

That is not what any of the vaccine studies have said so far. I haven't read this one, but I bet it also doesn't say this. The stated efficacy/protection percentages that have been presented so far have been for the reduction of _symptoms_. There haven't been any studies on vaccines preventing infections, probably due to lack of resources for testing everyone in a trial multiple times.

IANAD but I'm nearly positive you're incorrect. I spent last night puzzling over what "efficacy" means vis a vis this video: https://www.technologynetworks.com/immunology/videos/covid-1... The author explains that the efficacy number is derived from the the number of the number of people in the control/placebo group infected divided by the total number of infections in the study. 76% efficacy means that, for a given…

[deleted]

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#68

Post by Veen »

password321 wrote: post #58

Strangely, this news went under the radar: https://www.bmj.com/content/372/bmj.n149 23 deaths in Norway, possibly from vaccine.

First, it was 33 people out of around 50,000 elderly and vulnerable people who were vaccinated. Your source is outdated.

Second, it went under the radar because it's probably not attributable to the vaccine. The people who died were over 80 and already extremely frail with pre-existing conditions. They either died from those conditions or from their inability to cope with the mild side-effects of the vaccine, which everyone already knows about. Death rates in Norway are well within the historical range, so it's fairly likely that there were no excess deaths caused by the vaccine at all.

Their dying after having the vaccine does not mean they died because of the vaccine.

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#69

Post by endgame »

thehappypm wrote: post #65
ummonk wrote: post #48

The case for a one-dose first strategy gets stronger and stronger, but due to slavish proceduralism, the FDA wouldn’t consider it.

There is 0 data that any of the vaccines approved by the FDA are efficacious with a single dose. There is 0 data to support that a delayed dose is efficacious. The FDA is making a very, very valid choice so far.

There is also minimal data that parachutes are better than placebo for people who jump out of planes. This situation needs wartime thinking, not peacetime proceduralism.

What you're saying is that we must assume the worst case, that the FDA-approved vaccines are like 2-pack epoxies: that first doses give 0% immunity, and all the efficacy comes from applying the second. That seems completely absurd.

Re: Oxford vaccine shows sustained protection of 76% in 3-month gap til second dose

#70

Post by lbeltrame »

nmca wrote: post #16
lbeltrame wrote: post #9

Earlier quoted context omitted.

It is a reduction of the risk of symptomatic disease by 76% once vaccinated. But more importantly, there were no hospitalizations or deaths in the vaccinated people. This is a point the media often overlooks.

Because the "no hospitalisations or deaths" claim from the first Oxford paper was comparing n=2 to n=0 and thus was miles from significance. If the new paper has updated data on this happy to be corrected.

It is a constant in any vaccine, including the "lowest" performers from Sinovac and Sinopharm. At this point, I'm inclined to believe that any resonably effective vaccine will have this effect.
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