This simplified risk assessment makes the point that when Covid-19 is epidemic there is more danger from the virus than from the AstraZeneca vaccine. However, is that the right metric? While the risk of death from AZ and similar vaccines is around one in a million, the risk from Pfizer and other mRNA vaccines is nil. And on the other side of the equation, the risk of contracting C-19, the risk of death, the risk of serious and long term side effects, and the risk of passing C-19 on to vulnerable family members are all much higher when vaccinated with AZ and similar vaccines than when vaccinated with mRNA vaccines. 

The reasonable conclusion would be that AZ is probably better than nothing, but no-one in their right mind would choose AZ over Pfizer, and no responsible health professional would encourage anyone to have an AZ vaccine rather than an mRNA vaccine. 

Hi Peter,

Until we know the overall facts (which could take some time) we will not know if your view is correct or not.

Pfizer has its own 'reaction' issues but these have not been broadly researched or publicised. Pfizer is showing a significantly lower efficacy against the Delta variant in early data from Israel - we do not know if AZ will be better or worse!

It could be that having both the AZ and the mRNA vaccines gives better immunity to multiple variants of this COVID virus...who knows?? I certainly don't. I've had the 2 AZ shots and would be happy to 'top up' with Pfizer as well, subject to everyone else having been offered the opportunity to get vaccinated.

Glenn,

Now you argue that there should be no comment on the failings of AZ "until we know the facts". However, that wasn't an inhibition to your previous advocacy of the AZ vaccine. 

In a number of countries which have access to mRNA vaccines AZ is being dropped, based on the very clear data that AZ is a second rate vaccine. In Australia, they recommended that AZ not be administered to anyone under 60 because of the risk of death from blood clots. It was argued that because the risk of C-19 death was higher in older people, and due to a lack of mRNA vaccines due to a Government bungle, it was worth the risk in using AZ for the aged until better vaccines were available. In South Korea, they dropped AZ and even stopped giving second doses to people who had had a first dose. In the US, they have relied almost entirely on mRNA vaccines. AZ and similar vaccines continue to be used where better alternatives are not available, but no responsible health professional would recommend AZ over Pfizer except in the most extremely unlikely circumstances.

The reality is that AZ had a significantly lower efficacy compared to Pfizer in relation to the original C-19, and that gap has widened significantly in relation to the Delta variant. The only upside in AZ, and it is an important upside, is that it is reasonably effective in stopping short term severe symptoms. Given that you weren't one of the few unlucky ones suffering blood clots causing death or permanent brain damage, its good that you had your AZ vaccine because it has made you safer than if you had no vaccine. 

Peter,

Your comments and views are appreciated.

I certainly was not arguing or suggesting as to "no comment on the failings of AZ "until we know the facts"." 

Thanks Glenn and Peter for an interesting discussion that highlights the headline. My concern is that, when numbers are quoted as comparisons, the assumptions behind them are often not stated. The assumption in the  UK data in the post is clear ie it's with getting COVID there in the next 90 days. 
If that is the same assumption used in the ATAGI advice a few weeks ago it would seem that their advice needs to be quickly revised due to the delta variant and the non availability of Pfizer. Unless of course we can stay in lockdown until much more Pfizer arrives in September. 

@ Lynn, 

Yes. Risk assessment requires consideration of both the risk and the proposed mitigation. There is no doubt that in much of the developing world AZ looks pretty good. It is cheap, it is relatively easy to distribute, and it reduces harm from C-19. Even balanced against the harms caused by the vaccination itself, and the reality that its low efficacy means that transmissions continue, AZ would be advisable if superior vaccines are unavailable.

However, even with C-19 numbers increasing from a very low base, the case for AZ use in Australia is still weak. AZ takes 13 weeks to reach its (limited) maximum effectiveness while the mRNA vaccines take 3 weeks. Pfizer or Moderna could be procured and distributed in Australia to gain effective cover within the time frame in which AZ could provide some protection. And if the Government doesn’t want to supply an effective, high quality vaccine to all Australians then the country should stay in lock down. Individuals should not have to risk their lives by taking AZ for the sake of getting others out of lock down.

The selection, procurement, distribution and administration of C-19 vaccines in Australia has been bungled by the Australian Government and its public servants and advisors. Much of the continued advocacy for AZ is essentially just attempting to paper over that bungling. And now Scott Morrison is pushing for wider use of AZ because his approval ratings have fallen. I suspect he wants to create an image where he is in opposition to the past vaccine rollout, and that he is the “action man” speeding up the rollout so we can all get out of lockdown. Tragically, that could lead to more AZ deaths compared to achieving the same number of vaccinated citizens using mRNA vaccines.

Times have changed

https://www.smh.com.au/national/doing-the-maths-on-astrazeneca-20210727-p58d81.html

Lynn,

... and the situation - including the risk factors - will keep changing.

Thank you for the additional input.

Glenn