[Toenex]

I suspect the bulk of the population will receive the 'Oxford' vaccine. It's still going through the approval process but the UK has ordered more of it. I believe the Pfizer vaccine is targeted to front line workers and the clinical vulnerable.

[SubiculumCode]

Why? The 'Oxford' vaccine has been pretty shaky. Edit: source: https://www.wired.com/story/the-astrazeneca-covid-vaccine-da...

[rjtavares]

Source? Latest news[1] seem to indicate it's effective.

[1] https://www.bbc.com/news/health-55040635

[marcosdumay]

Yeah, there was a ton of news on that vaccine last week.

After a bit of push-back the laboratory acknowledged that this 90% efficacy was comparing a much younger vaccinated population than the one that got placebo.

That has put some doubts on the entire procedure (with countries forcing them to publish details), but it doesn't look like a real problem right now. Anyway that one high efficacy result is very likely flawed.

Anyway, what I get is that the important part is this: "Nobody getting the actual vaccine developed severe-Covid or needed hospital treatment."

[SubiculumCode]

Potentially.

[1]https://www.wired.com/story/the-astrazeneca-covid-vaccine-da...

[lbeltrame]

There's another readout expected in the USA sooner or later, with a far larger cohort (30K people), but for the full/full dose regimen.

[rjtavares]

Thanks!

[sweezyjeezy]

We don't need the super-high efficacy numbers (>90%) that the other vaccines are reporting for this to stop the virus. Typical flu vaccines are ~ 50%, I think the Oxford vaccine's results show that they've achieved this.

[d_tr]

The efficacy does not need to be super-high, provided enough people decide to actually go get vaccinated, and the percentage of skeptical people seems to be quite high.

Plus, any given vaccinated individual would have to rely less on others being vaccinated as well.

But I am grateful that vaccines got developed and tested so quickly anyway.

[Toenex]

Yes I think they only need to hit 50% for approval. Conservatively they were getting 62% as I recall and the 'experimental endpoint' dose got them to 90%.

The Oxford vaccine is far cheaper (15x) and easier to store so long term it has a lot of competitive advantages.

[kokey]

There's certainly been issues with how parts of the trial was run. However, it's not insurmountable. It's possible to untangle some of the past data and the trials aren't over yet and these aren't the last trials so we will have better data soon and it could all check out. This vaccine is appealing in particular because it's a lot cheaper to make and a lot more straightforward to distribute and even with questions over how the trials were run it's still looking like the good results will probably hold up mostly.

[bealesd]

I don't think it has been shaky, it has > 90% success rate (1.) when administered as a half dose followed by a full dose.

1. https://www.theguardian.com/uk-news/2020/nov/23/oxford-covid...

[nmca]

My understanding is that that trial condition (half->full) was administered accidentally (thus not pre-registered) and nobody expected it to work better, and the sample size is small and on the wrong age groups.

[spuz]

This doesn't matter though. The results are still valid.

[KingOfCoders]

How could numbers in a "controlled" trial be valid if they are arrived at by accident?

[Toenex]

The half dose was an 'experimental endpoint'. Always planned but not seen as critical. FDA rules now stipulate you can only register on primary endpoints declared before the trial starts. I suspect AZ have argued that the accelerated nature of the process should take this into account.

[regularfry]

"Controlled" doesn't mean what you think.

[gns24]

No, the results are not valid, or at least not in a useful way. The group who have received the wrong dose isn't a random sample from the treatment group, so we don't know whether it's more effective or not. It could even be less so.

I don't know what the regulator will do about this situation; it's clear that the vaccine is effective in at least one of the dosing regimes administered, but being entirely certain as to which is better is probably impossible to determine from the data available.

[spuz]

My understanding is that the results are still useful and can be include in the statistical analysis. This is what I heard form the BBC's Newscast podcast

https://www.bbc.co.uk/sounds/play/p08ztv8h (starts around 7:30)

Professor Jennifer Rogers (clinical trial statistician):

> "There was some planned dosing differences anyway but this one happened by accident. Now that doesn't mean these results are completely invalid - doesn't mean that at all. You can make changes to your protocol and you can make changes to what you're gonna analyse all the way up until you actually see your data.... If you haven't seen what the data looks like, you are allowed to make changes to your protocols and it is quite common, it does happen that people make changes as to what they're going to analyse.

> "So this change was carried out with discussion with the regulators so it was all fine..."

Now I tried to find the same information reported online and I found this from the same Professor:

https://spectator.com.au/2020/11/what-we-know-so-far-about-t...

> It is perfectly acceptable to make changes to the protocol prior to database lock, so the protocol could have been updated to include this additional analysis (the point of closing a database is to ensure a trial can remain blind, meaning researchers can’t carry out ad-hoc analysis or potentially selectively report results before proper analysis takes place). However, according to version 14 of the protocol, dated 9 November 2020, the primary analysis was set to be the efficacy of two doses of vaccine (across both half and full dose), with secondary analyses being the efficacy of at least one full dose and efficacy of two full doses of vaccine. Efficacy of half dose with a full dose booster was not considered as a secondary analysis in the protocol and so could be an ad-hoc analysis post database lock.

So I'm not actually sure whether AstraZeneca announced the change to their analysis before or after they started looking at their results. If they announced they were going to include the half-doses before database lock then they can use them as valid results.

[oxfordmale]

Ignoring the 90% that is was based on a population below 55, a 70% efficacy is still a success for the Oxford vaccine, as it can be stored in a regular fridge. This makes distribution outside health settings much easier. I would happily take the Oxford vaccine if it was offered to me.