Vaccine nostalgia?

Goodbye Astra-Zeneca COVID vaccine. 

It seems a long time ago now that I chose to protect myself against Sars Cov-2 with the vaccine developed in Oxford and manufactured by Astra Zeneca. Now it’s time to say goodbye and thanks.

RCT evidence was clear about the effectiveness of the vaccine, and I hoped it would provide a low mortality way out of the pandemic, mean the end of lockdowns, as well as reductions in hospitalisations and deaths. 2 billion doses in 170 countries later falling demand means it has now been withdrawn to become history. Of the 37 million people in the UK who received boosters, only 48,000 were from the AZ vaccine.

A brief history

The vaccine was developed by Oxford University, its arm length vaccine development company Vaccitech, and manufactured by Astra Zeneca who, initially at least, decided not to profit from the vaccine. It was a vector vaccine, using a modified chimp virus to carry DNA coding for the spike protein. 

The cells so affected (transfected) would create mRNA from the vaccine DNA, manufacture the protein which would then be recognised by the immune system creating immunity to real viruses containing the spike protein.

Chimp adenovirus was used to reduce the chance that human immunity to common adenoviruses would destroy the vector before it could deliver its DNA. An added advantage was not being subject to the need of the mRNA vaccines to be kept at low temperatures, and way cheaper too. 

Problems

It was rolled out at the same time as Britain’s idiotic separation from the EU, and promoted by UK’s jingoistic politicians, (who at one point wanted to put union jack flags on each vial!). Politics at that time, as well as making crucial errors in managing the pandemic, got in the way of wider distribution with unseemly spats between European nations and the UK which should not have happened. 

It has now been withdrawn for several reasons. Rare but significant side effects were an early problem, it has not been upgraded to the new variants, there are better vaccines around and sales have plummeted. Is this an admission of failure like I’m sure some will claim? I don’t think so.

Early in the pandemic it worked well and has been estimated to have saved 6 million lives in addition to the economic benefits from avoiding the need for lockdowns. The rare side effect of TTS (Thrombosis with thrombocytopaenia Syndrome) – blood clots in association with the consumption of platelets (tiny cells responsible for blood clotting) became evident in April 2001 and this meant its use was modified in younger people and those at risk of thrombosis. Later that year, potential mechanisms for this problem were uncovered

It was due to interactions between the adenoviral vector binding electrostatically to key proteins responsible for blood clotting.  The risk of death is about 1 in a million, which, given the huge roll out, resulted in hundreds of deaths globally. In the UK, the compensation scheme for those significantly affected has been, to say the least, slow in arriving and inadequate in its scope (why is the UK always like this?) resulting in families resorting to take Astra Zeneca to court.

As with all vaccines the benefits must be calculated according to data. Not having an illness is not a real individual experience, and relies on data to define, while side effects are felt and real.

Dodging the antivaxxers

It seems curious to me that much of the effort of anti vaxxers has been directed again the mRNA vaccines, endlessly manufacturing bogus anxieties regarding ‘experimental gene-therapy’ which largely seems to have escaped the DNA based AZ vaccine, whose genetic material is transferred to the cell nucleus to create mRNA and then back out into the cytoplasm to create the spike protein, just as do DNA viruses such as herpes, hepatitis B, smallpox and wart viruses do in the fluffy and cuddly ‘natural’ world that is one of antivaxxers driving fantasies.

Of course, the world’s leading antivaxxer, Joe Mercola couldn’t resist an early dig. This was based on affiliations of a co-founder of Vaccitech a sponsor, Wellcome’s foundation for Human Genetics, who Mercola bizarrely claims to be Eugenicists because they think overpopulation is causing problems. He then got busy on his many other profitable ways of scaring and misinforming his readers and had little more to say about this DNA based vaccine.  

That it was not subject to the scaremongering of the mRNA vaccines is perhaps a testament to how much of the antivaccine industries output is based in the USA and targeted to their own vaccines.

Looking back, the AZ vaccine filled a gap and provided immunity for millions of people, was readily available, cheap, and easy to transport and store. Despite its failure to endure as an option, I see it as a success for science.

What next?

It is now part of history. A history which would, ideally, be useful in preparing for the next global pandemic. Prior to the emergence of Sars-Cov-2, it was anticipated this would be caused by flu. 

That process could be slowly under way with the increasing list of mammals affected by the bird flu pandemic caused by the H5N1 strain which originated in China in 1996. The H5 clade 2.3.4.4b emerged in 2020 and has sadly decimated bird populations, infected increasing number of mammals, and now has been infecting humans in close contact with 36 dairy herds across nine states affected in the USA. 

While often a mild disease, it has killed 50% of those few hundred people know to have been infected. Vaccines are on their way, including a mRNA vaccine which would be available more rapidly than ‘traditional’ vaccines. As yet, as there is no evidence of human-to-human spread. H5N2, another bird flu strain, has infected and killed a man in Mexico with no contact with birds which is of concern. Reassuringly, no close contacts tested positive.

If human to human spread does place, more history of vaccine development will be rapidly written , but that’s another story.