Oxford Vaccine Approved In Australia

[bhobba]

The Oxford vaccine was approved here in Aus - finally:
https://www.tga.gov.au/media-release/tga-provisionally-approves-astrazenecas-covid-19-vaccine

It recommends a second dosing 12 weeks apart. The article in the local paper announcing this said with a 12 week second dose it had 82% efficacy. This was the finding of the Lancet preprint:
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3777268

Associate Professor in infectious diseases, Dr Michelle Ananda-Rajah, from Monash University, has doubts about the paper (and after reading it the statistician in me does as well):
https://healthcareworkersaustralia.com/2021/02/11/backing-up-our-gains/

In the comments section of the story I posted this. There is all sorts of stuff that gets posted from the virus does not even exist, to it is just another flu, to antivaxer nonsense. They seem to be fine - but the article by a well qualified associate professor calling for caution on the findings of the preprint (which is exactly why you have preprint and peer review) was deemed not suitable - and my post removed. I had a chat to my sister about it and she said you are not a doctor - why are you commenting on it. She knows I have a degree in math including a significant amount of stats that I also used in my job on occasion. I said - I am concerned about the statistical validity of the study. She was not impressed and said - I do not want to talk about it and walked off.

It makes you wonder - it really does.

BTW I will be asking for the Oxford vaccine with the second dose 12 weeks apart since, while there is reasons to be cautious of the findings in the preprint, I see no harm in waiting 12 weeks.

Thanks
Bill

 

[PeroK]

Associate Professor in infectious diseases, Dr Michelle Ananda-Rajah, from Monash University, has doubts about about the paper (and after reading it the statistician in me does as well):
https://healthcareworkersaustralia.com/2021/02/11/backing-up-our-gains/

The problem with this piece is that it is as much politics and personal opinion as science. Take the last paragraph:

"Whatever the outcome of our strategy, there is no looking away from the inferno beyond our shores. Unless this is extinguished through global citizenship with rich helping poor, embers will seed outbreaks for years, threatening our national security and acting as a drag on our pandemic recovery. Australia is a jewel, an outlier, confirmed by its ranking of 8th in the world in pandemic response by the Lowy, well ahead of the UK at 66 and the US on 94. For a nation that has done so well and come so far, we ought to be ambitious by backing up our gains with the most adaptable and potent vaccines that will help us accelerate rather than limp out of this pandemic. The best vaccines will supercharge our recovery transitioning us from living to thriving, enabling a strong Australia to pay off its debts and help its neighbours in line with our core values as a people."

That's hardly a scientific analysis; let alone an analysis of the science!

The scientific points at issue are simply:

1) Whether to use the AZ vaccine.

2) If so, whether to restrict it to the under 65 age group.

 

[bhobba]

That's hardly a scientific analysis; let alone an analysis of the science!

Good point - it did intermingle personal views with scientific ones. Not a good look.

BTW there are some on the good doctor's twitter feed now pointing exactly that out.

Thanks
Bill

 

[Ygggdrasil]

It recommends a second dosing 12 weeks apart. The article in the local paper announcing this said with a 12 week second dose it had 82% efficacy. This was the finding of the Lancet preprint:
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3777268

I do agree with the criticisms that the statistics for the paper are not great (mainly because of small sample sizes). For example, the claim that the second dose had 82% efficacy was based on testing ~1300 individuals in the vaccine and control groups, a factor of ten smaller than the number of individuals tested in the Pfizer-BioNTech and Moderna phase 3 trials.

There are good scientific reasons to believe that a longer delay between doses would make the vaccine more effective, but more data is necessary to confirm. That said, I'm not opposed to the decision to approve the vaccine.

I will note that there are good reasons to be skeptical of "secondary" outcomes from clinical trials. The primary outcome of a trial is the one that the outcome that the trial set out to test (in the case of COVID-19 vaccine trials, this is usually the amount of symptomatic infections). Secondary outcomes are outcomes that were also measured. The problem of trusting results from secondary outcomes is one of multiple hypothesis testing. If you measure enough variables in a study, you're virtually guaranteed to find one outcome that is a statistically significant outlier by chance.

Physicists should be well aware of this phenomenon. For example, in the data collected from the LHC to find the Higgs Boson, researchers found a statistically significant 750 GeV diphoton excess in the data that many took to be a sign of a new particle. However, in subsequent tests to confirm the signal found that the "new particle" did not actually exist and was just a random statistical anomaly in the original dataset. The worry here is that some of the secondary findings of the Oxford-AstraZeneca trials that the researchers have been pointing at to distract from the relatively poor primary outcome of 62% vaccine efficacy are similar statistical anomalies in the trial data.

 

[bhobba]

The problem of trusting results from secondary outcomes is one of multiple hypothesis testing.

Exactly - each hypothesis should have its own experimental design. That is my 'statistical' objection. The results they obtain could be valid, but need to be backed up by a properly designed study before stating it in a story about the vaccine that the public will be using to make decisions on what vaccine to get - if they get the choice. They may not here in Aus because we have enough Pfizer to do half the adult population ie the at risk groups and those working with them. If my doctor gives me the choice I will take the Oxford vaccine with the second dose 12 weeks later because I am personally very carefull. But that is just me. I was just watching a discussion on the TV and the valid point was made by the time most people actually get the vaccine more information will be known and not to really worry about it till them. Probably, pragmatically, the best advice.

We will be starting vaccination using the Pfizer, from the 22nd. It will not go to the most vulnerable at first, but to those looking after the most vulnerable and front line workers. But only at major hospitals at least initially. I am not due until later - how much later I do not know. Vaccination with the Oxford vaccine will start in early March at first by GP's, then later by government set up clinics, and possibly later even pharmacy's. I will see my doctor beginning March to find out the full 'go'.

Thanks
Bill