As if its name hadn't been drawn through the mud enough already, the AstraZeneca vaccine now finds itself at the centre of a potential safety issue.

On top of earlier controversies over supply, its suitability for older people and its efficacy, administration of the vaccine has been paused in Ireland and several other countries after a small number of serious blood clotting events in Norway.

The irony is that the criticism and doubts around AstraZeneca's vaccine are mostly unjustified. But this won't lessen the consumer resistance it was already facing, which will be magnified following the decision to suspend its use pending investigation by the European Medicines Agency (EMA).

Hospital Report

The first charge made against the vaccine last year was that it was less efficacious than others. It didn’t help that, due to an error made during the AstraZeneca trial when volunteers were given a half-dose, an early set of results was confusing.

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Different trials for different vaccines are performed in different ways and it is not fair to compare them directly. In any case, AstraZeneca has gone on to show impressively high effectiveness in real-world trials.

Then Ireland and other countries got cold feet over using it in older people – correctly – because of the lack of data from trials. Again, real-world evidence – which is what matters – later showed its effectiveness in this age cohort. Consequently, our regulators reversed their stance on this last week.

Correlation, not causation

The latest controversy arose after patients in Norway suffered serious blood clotting events after being administered the AstraZeneca vaccine. Correlation is not causation; just because one event happened after another does not mean the second was caused by the first.

What alarmed Irish regulators was the fact that the affected patients in Norway suffered serious clotting, some in the brain, and were aged under 65.

The Norwegian example has divided countries and scientists. The fact that the Netherlands, Germany, France and Italy have followed Ireland in suspending vaccinations would seem to vindicate our regulators' decision; but the UK and Canada continue to administer the vaccine.

Some Irish scientists have disagreed with the decision of the National Immunisation Advisory Committee; prominent scientist Prof Luke O'Neill has described it as disturbing and unnecessary.

Has he a point? Just two, non-serious reports of clotting have been made in Ireland. AstraZeneca says there have been 15 instances of deep vein thrombosis and 22 events of pulmonary embolism reported among more than 17 million people vaccinated, with no evidence of a causative link. Might it have been better to wait for a collective response from the EMA, rather than to take a cue from a single national regulator?

Litigation culture

Could Ireland’s litigation culture have played a role in the “abundance of caution” shown by the regulators here? They may have been mindful of claims made in recent court cases around the swine flu vaccine that insufficient regard was paid to international reports of adverse reactions in that campaign in 2009.

Developed in Oxford, the AstraZeneca vaccine has been branded as a British vaccine by Boris Johnson’s government, eager to score successes in the post-Brexit world. As a result, there is a political tinge to much of the narrative around authorisation and supplies.

The company’s about-turns on deliveries to Ireland have understandably frustrated the HSE and the Government. But with its price one-tenth of some rivals, it is as close to a “people’s vaccine” as we have in this pandemic.

The EMA will adjudicate on the clotting issue this week, but whatever its decision, the damage to the reputation of the AstraZeneca vaccine is massive and possibly lasting. Health unions had already expressed a preference for other vaccines arising from the controversies mentioned above. Telling people to be on watch for blue spots on their skin after getting the vaccine won’t help.

And yet for many groups, the danger of falling ill from Covid-19 appears to be far greater than the threat of blood clotting from this vaccine, based on what we know so far. A fraction of the 30,000 people who were supposed to get it this week will contract the disease, and some may even suffer serious illness. Where is the precautionary principle being applied here?