This whole thing is crazy. On one of our expert panel shows, the best known one in fact, called Q&A, last Thursday they had a discussion with immunologists etc on the vaccine. At the moment here in Aus we are churning out over 50 million doses of the Oxford Vaccine. After that we will churn out over 50 million doses of the Novavax vaccine - or buy it in - our manufacturer CSL has not decided yet - it is likely however we will make it to prevent supply problems like with the Pfizer Vaccine. We have 20 million doses (enough for 10 million people - 1/5 of our population) of the Pfizer vaccine to be rolled out at the end of the month, the Oxford in March sometime. One of these 'experts', Dr Michelle Ananda-Rajah, made the claim forget about the Oxford vaccine, and go straight to the Novavax vaccine because the Oxford vaccine only has 63% efficiency while the Novavax vaccine has 95% efficiency (from early phase 3 results). None of other 'experts' challenged her on that. I was sitting there thinking what's going on here - haven't they seen the latest data on the Oxford vaccine?
https://www.astrazeneca.com/media-c...the-primary-analysis-of-phase-iii-trials.html
One dose - 76% effective. After 12 weeks you get the second dose - 82% effective.
She has interesting views:
https://twitter.com/rajah_mich?ref_src=twsrc^google|twcamp^serp|twgr^author
Below she acknowledges the new data about efficacy, but still took it at 63% because she has some doubts about it (which seems to be the reason she didn't mention it):
https://healthcareworkersaustralia.com/2021/02/11/backing-up-our-gains/
To me the road ahead here in Aus is obvious - high priority groups get the Pfizer, we give one dose of the Oxford as fast as possible to the rest of Aus. Then the second dose 12 weeks later. It will probably take longer than 12 weeks to give the first dose to everyone - it is estimated October, so 3 months after that for everyone to get the second dose. Once the Novavax vaccine is manufactured it can then be rolled out - exactly when depending on how it interacts when already vaccinated with the Oxford or Pfizer and how long the immunity lasts - but I suspect next year sometime. Australia, being in a very good position, deliberately has decided to wait a while and get the data from other counties vaccine use before proceeding. And I think it was wise - we now know the most effective dosing for the Oxford vaccine. I am in the priority one group of 16 million so I may or may not get the Pfizer - personally though I would prefer the Oxford because I take strong precautions - leave the moderately more effective vaccine for those that may not be as carefull as I am.
But as the good doctor/immunologist correctly points out it will not get us out of trouble - many restrictions will still remain here in Aus. It will be less when the Novavax vaccine is rolled out, but I personally doubt even that will do it. I fear we are in for, an admittedly lessening, level of restrictions for a few years yet, until things get back to normal.
Added later
Actually had a reply from the good doctor to my twitter post. Her blog I posted made some valid points:
'Announcement on Feb 1 of increased efficacy by spacing two doses of the AZ vaccine at least 12 weeks apart generated some interest. This post hoc analysis of the primary clinical trial data should be interpreted with caution. Post hoc analyses aim to ask a question rather than answer one. Why? Because they rely on analysing a slice of the main trial data; have greater uncertainty around estimates because numbers analysed are usually smaller and are prone to bias which may translate to inadvertently finding patterns where there are none. This sub-study provided the rationale for the UK vaccine authority’s decision to delay the interval between vaccine doses to at least 12 weeks in order to vaccinate more people. However, a quarter of a year is a long time to wait in the middle of a pandemic. This sub-study actually raised more questions than answers (as post hoc analyses often do!). Why was the efficacy of a single dose of the AZ vaccine at preventing symptomatic infection higher than two standard doses at 76% versus 63% respectively? In other words, vaccine efficacy seemed to decline with a second dose. This trial update contained an additional 5,541 people from SA, UK and Brazil but overall vaccine efficacy with two standard doses remained unchanged from the first interim study published on Dec 8 which led to approvals in several countries (i.e. 63% among 14,379 people in this update vs 62% in the first analysis). Reassuringly, there were no hospitalisations after the second vaccine dose (n=0 with vaccination vs 15 with control). These results will reassure Britons that delaying the second dose by 12 weeks has some supportive evidence. However, for the rest of us, we keenly await the release of the AZ trial predominantly from the US with >32K people where close to one quarter will be over 65 years, due to report in the next month or so. In this large trial, people are receiving 2 standard doses 28 days apart- potentially the dosing schedule we will receive if approved, hence discussions on single dosing and delayed interval dosing of 12 weeks are largely academic for Australia.'
The statistician in me (sigh) unfortuneately agrees. There goes another 'good' idea. We can alter the timeframe of our second dose, but for some reason she seems to think the dosing schedule here is going to be 28 days. We have, lies, damned lies, and statistics or as my stats prof used to say - stats is like a bikini, it's the bits you don't see you want to know about. However trials, as detailed in my first link, are proceeding with different dosings and times between the second shot.
Thanks
Bill
