News Coronavirus The Stats Guy: Weighing up the AstraZeneca vaccine? It’s a matter of data and emotion

The Stats Guy: Weighing up the AstraZeneca vaccine? It’s a matter of data and emotion

Simon Kuestenmacher
TND's stats whiz explains why he chose to get the AstraZeneca vaccine. Photo: TND
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Coronavirus variants, vaccines, risks, the costs of lockdowns? It’s hard to make sense of all these numbers. As a demographer I am very much not qualified to give medical advice, but I can give statistical advice and walk you through my decision-making process.

All the COVID talk these days is about the Delta variant. This new version of the virus is about 50 per cent more transmissible than the Alpha variant (which itself was about 50 per cent more transmissible than the original Wuhan virus, according to the World Health Organisation).

Last year it took minutes of contact to catch the coronavirus, today you can catch Delta through ‘fleeting contact’. That’s why masks are mandatory outside.

The public health goal is to have as few people as possible catch the virus. Look at the excess death figures for India and Brazil to see why we locked Australian cities down at first sight of an outbreak.

Lockdowns, the necessary evil

Lockdowns unfortunately have endless negative side effects. Our mental health suffers, we get fatter, we delay routine healthcare, incidents of depression and domestic violence rise, more of us suffer financially, reports of people feeling lonely and hopeless are on the up.

I don’t need to tell you that lockdowns suck, right? However, for most of 2020 lockdowns were the only tool we had to combat the virus. A necessary evil.

We can’t just willy-nilly open up the country and pretend there wasn’t a Delta wave ripping through the nation, as the short-sighted protesters call for. Ignoring the reality of a pandemic isn’t an option, no matter how many horses you punch.

The health advice from all credible sources couldn’t be clearer. The best way to protect yourself against Delta is to have a fully vaccinated population. Different institutes come up with slightly different targets. On Friday, National Cabinet reached an in-principle agreement to stop city-wide lockdowns and reinstate most pre-COVID freedoms once 80 per cent of the eligible population is fully vaccinated.

The deal is simple, once almost everyone is vaccinated, lockdowns are history. Cool. So, let’s get vaccinated. But how and when?

Waiting for Pfizer? Consider this first

If you have a vial of Pfizer and one of AstraZeneca in front of you and both are available in unlimited quantity in the country, pick Pfizer. Compared to AstraZeneca, Pfizer puts you at a slightly lower risk of experiencing soft side effects. Pfizer avoids blood clots altogether and offers a slightly higher rate of protection against hospitalisation or death.Spoiler alert: In Australia we have plenty of AstraZeneca but little Pfizer available for now, so the unlimited supply scenario doesn’t play out. You won’t find yourself in a position where you get to choose your vaccine anytime soon.

Should you just wait until Pfizer (or later Moderna) will be available to you? This depends on your own propensity to take risks, how much you care for the health of others, how much you want to stop lockdowns, how much you want your right to travel back, how much you want to help the economy.

Your hesitation most likely stems from the blood clot deaths linked to AstraZeneca. Articles on the topic always say stuff like “extremely rare blood clots” but fail to really put risks into perspective. We expect one death for every one to two million AstraZeneca jabs. To vaccinate 80 per cent of the population, we must vaccinate 16 million Australians with 32 million jabs. So far 12 million of these jabs have already been administrated. If all remaining 20 million doses were AstraZeneca (which won’t be the case) we would expect 10 to 20 deaths.

An insufficiently vaccinated population either means that the virus will circulate for longer in our community and kill people, or more likely that millions of Australians will continue to go in and out of lockdowns. A population below the vaccination target will be treated as an unvaccinated population by public health teams. No amount of complaining, protesting, or swearing at politicians will change that.

The virus and the vaccine have very different types of risks associated with them. The virus has multiplicative risks and vaccines don’t.

The side effects of the AstraZeneca vaccine are real, but they are small and not contagious. This means they follow a linear growth pattern. One million AstraZeneca jabs will kill a maximum of one person, ten million doses will lead to no more than ten deaths. Linear growth at a tiny scale.

Meeting a population that is neither locked down nor vaccinated (like in India), the virus spreads exponentially. This results in extremely high case and fatality numbers in very little time. No wonder we want to avoid this at all costs.

You must personally weigh the insanely small linear risk of potentially harming yourself by getting vaccinated (literally a one in a million chance) against the exponential risk of catching the virus if it continues to circulate in Australia or continuing to live in a world of closed borders and locked down cities.

When making your decision you will want to make sure to correctly estimate the order of magnitude of risks and rewards. Are you only thinking about your own health or are you taking collective needs into consideration? Are you willing to take on a small personal risk for the collective good as well as your own freedom?

Further you will need to be clear about your predictions about the future. I, for one, expect cross-border travel, attendance at events, employment opportunities, and other personal freedoms to be linked to your vaccination status through a vaccine passport before the end of the year. Your view of future policies should inform your decisions today.

Why I chose AstraZeneca

In case you are interested in my decision, I’m 38-years-old and I booked my AstraZeneca jab as soon as they were made available to those aged under 40.

I happily took the one-in-a-million risk to my own health to increase the likelihood that my family doesn’t see Melbourne lockdown 6.0.

I got the jab to help make it more likely that my family can travel overseas so my one-and-a-half-year-old son can finally meet his grandparents in Germany. To make sure the little fella can have playdates and partake in activities whenever we want. To ensure that borders across Australia are open so I can do my job as a public speaker, help my gym stay open, and to avoid anyone in our house going bonkers.

Your decision is up to you, I’ve made up my mind.

Demographer Simon Kuestenmacher is a co-founder of The Demographics Group. His columns, media commentary and public speaking focus on current socio-demographic trends and how these impact Australia. Follow Simon on Twitter or LinkedIn for daily data insights.

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