AstraZeneca jab benefits outweigh risks of side effects

16 April 2021

What remains clear is that the AZ vaccine is effective and performs much better than early expectations for first-generation vaccines

Australia remains in a fortunate position with COVID-19 , compared with nearly all other countries . We have no known community transmission. We also now have vaccine production of about one million doses a week. So why all the partisan pointscoring , anger, hysteria, panic and fear? Especially over the effective AstraZeneca vaccine?

The AZ vaccine has recently been associated with a rare side effect where there is unusual clotting around the brain and in the abdomen, but it remains unclear how often this occurs. In Britain, where the largest numbers of AZ vaccines have been given, there has not been the same number of events as seen in Germany and in Scandinavia, and that occurs more often in those younger. But these events are rare, associated with about one in 200,000 doses and deaths at about one in a million . This needs to be compared with the risk of death from COVID-19 itself. If you are over the age of 80 your risk of dying from the disease is more than one in 10; if over the age of 70, more than one in 100.

What remains clear is that the AZ vaccine is effective and performs much better than early expectations for first-generation vaccines. The main purpose of the vaccines was to stop deaths and the serious complications from COVID-19 . The AZ vaccine (along with many others) does this successfully, including against common variants such as the British strain.

Every drug and vaccine we use has side effects. Most are minor but can be common; for example, nausea, fever, aches and so on. But some also can be serious. The contraceptive pill is associated with a clotting risk of about one in 1000 women a year. A commonly used anti-clotting drug, heparin, also can rarely but paradoxically cause bleeding with increased clotting and by a mechanism similar to what is happening with the AZ vaccine. The Pfizer COVID-19 vaccine has increased numbers of allergic/anaphylaxis events.

With winter coming, and an increased risk for transmission, it is essential that we get those who are most at risk of dying or having serious complications from COVID-19 , especially those 70-plus years, vaccinated within the next couple of months. This should now be much less problematic . CSL in Melbourne is producing close to one million doses of vaccine a week.

Perversely, because Australia has been so successful at stopping the spread of COVID-19 , in the younger age groups where the risk of death from the virus is much lower, then balancing the comparative risks of rare side effects is more important.

But we also need to remember that those in the 50-plus age group in otherwise good health were not due to be vaccinated here until many months from now. By then we will have a lot more data to make much better informed risk versus benefits assessments . We will also have more supplies of other imported vaccines available by then, as global production increases.

From my perspective, for those 50-plus with risk factors, the benefits of the AZ vaccine still appear to outweigh the risks of rare side effects. We also have supplies of another vaccine (Pfizer) available that could be used instead.

When comparing ourselves with other countries, yes we do have lower vaccination rates than Europe and North America. But we also do not have uncontrolled transmission of COVID-19 .

There are few countries with minimal COVID transmission. New Zealand and Taiwan are examples , but both have lower per capita vaccination rates so far than here. Japan and South Korea, which had good control, but now have community transmission , also have lower vaccination rates than Australia.

COVID-19 is a global problem. Vaccines are in short supply and will be for some time to come. It is not reasonable or ethical for Australia to believe it should be at the front of the queue for everyone here to access these global vaccine supplies - just because we are richer and so can pay more for vaccines compared with countries that are much poorer than us and/or have uncontrolled spread of COVID-19 .

Yes, we need vaccines here and we need vaccine rollouts to be efficient . But we do not need to panic about a rare side effect or be part of pointscoring and blaming when the main problem so far has been a global shortage of vaccines. That needlessly contributes to making many people more hesitant about what are effective and safe vaccines.

Peter Collignon is an infectious diseases physician and microbiologist and a professor in the ANU Medical School.

This article was first published in The Australian