Pearls and Irritations

The Morrison government has provided Indemnity for vaccine manufacturers but not Australians at risk of the exceedingly rare, but sometimes fatal, blood clots linked to the AstraZeneca COVID-19 vaccine.

 On April 13, 2021, US health authorities recommended a pause in the rollout of the one-shot Johnson & Johnson/Janssen COVID-19 (adenovirus vector) vaccine. The delay is because six women have suffered rare but severe blood clots out of nearly seven million doses administered. As of April 13, 2021, there are no similar cases among more than 180 million people in the US who received the Pfizer BioNTech or Moderna (mRNA) vaccines.

Meanwhile, health authorities in other countries have taken varied responses to similar concerns about the AstraZeneca (adenovirus vector) vaccine:

• Denmark has become the first country in the European Union to drop AstraZeneca’s vaccine from its Covid-19 immunisation program.
• Finland and Sweden use it for those aged 65 and over.
• Germany, South Korea, Italy, the Netherlands, the Philippines, Portugal, Slovenia, and South Korea vaccinate those aged 60 and over.
• Canada, Belgium, and France vaccinate people over 55 years of age.
• Australia vaccinates those over 50 years of age.
• Greece and the UK vaccinate those over 30 years of age.
• Austria, Estonia, Ireland, Malaysia, and Thailand vaccinate those aged 18 and over.
• In New Zealand and Switzerland, the AstraZeneca vaccine has yet to receive marketing approval, while in the US, an application has yet to be submitted.

These different decisions reflect the difficulties of regulators, such as the European Medicines Agency (EMA) and the Australian Technical Advisory Group on Immunisation (ATAGI), on applying AstraZeneca’s adverse effect data on country vaccination strategy. The regulators agree that:

• There is evidence of a severe but rare side-effect Involving thrombosis (clotting) with thrombocytopenia (low blood platelet count) following administration. This reaction has a high mortality of up to 40%.
• Such clotting reactions have been one case per 25,000 Norwegians, 1 per 80,000 Netherlanders, 1 per 87,000 Germans, 1 per 150,000 in the European Union as a whole,1 per 250,000 Britons and 1 per 295,000 Australians; overall, around 1 case per 100,000 vaccinations.
• There is an increasing risk of severe outcomes from COVID-19 infection in older adults (and hence a higher benefit from vaccination) and a potentially increased risk of thrombosis with thrombocytopenia following AstraZeneca vaccine use in younger age groups.

The decision to continue to use the AstraZeneca vaccine depends on a risk-benefit analysis that includes the risk of contracting COVID-19 (short-term and long-term effects) in particular populations compared with the risk of these groups experiencing severe side-effects from the vaccine and the availability of alternatives.

These factors make decisions difficult; the risk-benefit ratio varies between people of different ages and the virus’s prevalence. The latter can also change. Decision-making data is graphically represented by the Winton Centre Cambridge.

In Australia, ATAGI recommends the Pfizer vaccine is now preferred over AstraZeneca’s in adults aged under 50 years. However, the latter can be used in adults where the benefits outweigh the risks, and the recipient has given informed consent. Given current limitations on the Pfizer vaccine supply in Australia, this situation might apply to people with underlying health conditions that increase their risk of a poor outcome from COVID-19 infection or aged care workers concerned about possible COVID-19 breakouts in nursing homes.

There are three ongoing issues. First, is AstraZeneca and Johnson & Johnson’s adenovirus vector vaccine technology causing the blood clots? The jury is still out. Second, how to diagnose and treat the specific “Vaccine-induced prothrombotic immune thrombocytopenia” (VIPIT). Guidelines are available. Finally, why hasn’t Australia introduced a no-fault vaccine injury compensation scheme to assist people who experience rare but severe vaccine side-effects? A no-fault vaccine injury compensation scheme recognises that if the government promotes community vaccination for the collective good, then it should also accept the ethical and financial burden for the few people who will sustain a severe injury. Many other countries have such schemes, including the UK, US, New Zealand, and Canada. Why not Australia?