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In Our Words: The basics of the AstraZeneca vaccine, what it is - and isn't

Let’s talk vaccines - again.

Let’s talk vaccines - again.

As I’ve done before with the Pfizer and Moderna vaccines, I’m going to use this space this week to give a quick and dirty review of the AstraZeneca (AZ) coronavirus/COVID-19 vaccine, one of two vaccines available in town lately. The eligibility requirements for it have dropped in both Manitoba and Saskatchewan to include much younger people and I know plenty of people here who have either got their AZ dose, who have made their appointment for it or who are considering it.

I know there are a lot of people who are hesitant about the AZ vaccine (and others) and if we're going to be making decisions like this that end up having an effect on public health, we should all be working off the same information.

I’ve scoured credible health sources - emphasis on credible - and spoken with health professionals about this. Here’s what I’ve found out.

I’m going to try to boil this down as well as I can, using no big words - at least, wherever I can help it - and nothing too complicated. I’m not trying to baffle you with bull. I want to relay information, especially for people who aren’t sure about the AZ shot or its side effects.

So, is the AZ vaccine safe? Short answer: yes. The long answer? Well...

Let’s start with the ingredients. The AZ shot is different from the other two vaccines currently available in Manitoba, Pfizer and Moderna - those two shots are mRNA vaccines, meaning that the key ingredients in those vaccines are a special piece of messenger RNA that sends a signal to the recipient’s cells to not take on anything that looks like the coronavirus. Think of it like a wanted poster in the wild west - the mRNA puts up a wanted poster with the coronavirus on it, telling the locals to not let that bad guy come ‘round ‘ere no more.

The AZ vaccine is different. It is what’s called an adenovirus vaccine. Adenoviruses are common viruses that typically can cause all sorts of ailments - diarrhea, fever, sore throat, pink eye, those sorts of things. The AZ one won’t do that - the virus is not active.

Both the AZ vaccine and the Johnson and Johnson vaccine are adenovirus vaccines.

This adenovirus isn’t used to give you a raspy voice or bad dumps. In this case, it’s used to deliver a DNA payload, like the Pfizer and Moderna mRNA, which cuts off the coronavirus’ ability to bond with cells. The DNA payload is that kind of wild west wanted poster here, warning the cells that they better not let that bad guy in.

The AZ adenovirus is a kind that humans haven’t encountered before - specifically, it’s an inert virus from chimpanzees. Like the coronavirus, it is novel to humans and the body hasn’t yet built defences or antibodies to it. It’s sneaky.

Once it delivers the payload, the adenovirus gets scooped up by the recipient’s white blood cells and is disposed of. It’s a suicide mission for the virus, but it pays off.

The rest of the ingredients of the AZ shot, much like other coronavirus vaccines, are meant to either keep the payload stable or to make it easier to bond once in the body. Aside from the adenovirus, the vaccine includes an amino acid called histidine and an amino acid salt, along with ethanol absolute, to make sure the good stuff isn’t contaminated. There are three different types of salt to keep the vaccine’s pH level safe for the body, as well as sucrose - yup, sugar. Another ingredient is polysorbate 80, an additive for several types of vaccines as well as foods like ice cream and whipped cream, which is used to make sure the vaccine doesn’t stick to the inside of the bottle. The last ingredient is water, meaning the AZ vaccine doesn’t need to be diluted - like an ice cold beer, it’s pretty much good to go right out the bottle.

This vaccine also doesn’t need those super-cold freezers we’ve heard about, like with the Pfizer vaccine - the AZ vaccine can be safely stored from 2-8 degrees Celsius.

It’s worth mentioning that none of the vaccines actually feature active coronavirus. These aren’t your standard flu shot, which contains a mild form of flu. These are cooler than that.

The AZ vaccine has been slightly less effective than the other two vaccines in clinical trials. While the other two vaccines have shown around 90 per cent effectiveness after two doses and a waiting period, AZ can be as low as 62 per cent with the same schedule.

Thing is, that’s at its worst. Other dosing schedules and trials have made it up to 90 per cent effective. In Australia, the vaccine is being administered as two separate shots about 12 weeks apart, which the country’s Therapeutic Goods Administration has at about 82 per cent.

The AZ vaccine has also got some bad press lately - namely, that it has been linked to rare blood clots. How high is the risk? Out of just under a million doses of AZ across Canada, clots have been reported in four people. They’re all alive and recovering now.

That’s somewhere around a one in 250,000 chance and nobody in Canada has died from the shot. Meanwhile in Manitoba, one in every 38 people has tested positive for COVID and out of that group, about one in 38 people has died from it. One of these things is not like the other.

What’s my opinion? Get it. Get it as soon as you can. Don’t pass up a chance because you want to get a Moderna shot - that’s like saving up to buy a flashy new car you might not be able to afford, when a used but decent car will do everything you need right now.

Some provinces are lowering their age requirements for the AZ vaccine faster than other vaccines. If it’s the first one my 26-year-old, Manitoba dwelling self can get, I’m going to get it. I’ll even swab my arm myself if that helps. My own mom got the AZ shot last month and she’s been fine.

This vaccine and others like it are our best bet to get back to something resembling a normal life - while “normal” wasn’t always great, it was certainly better than this.

Let’s do it. Get the shot.

Information contained in this column was sourced from the Centres for Disease Control (CDC), Health Canada, the Australian Therapeutic Goods Administration, the Australian Broadcasting Corporation, the World Health Organization, the European Medicines Agency and the Ontario and Manitoba provincial health ministries.

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