A leading Australian infectious diseases and vaccine expert has answered some of the growing questions about the country’s vaccine rollout, including the topic of choosing between AstraZeneca and Pfizer.
9News talked with Associate Professor Paul Griffin, who has worked on COVID’s frontline at the Mater Hospital in Brisbane. He has overseen more than 100 clinical trials of vaccine as a part of the Nucleus Network.
With the number of blood clotting cases in Australia due to the COVID vaccine now in the double figures, how concerned should we be?
Dr Griffin: Well, obviously, it would be better if we had a vaccine with no significant side effects, but unfortunately, such a vaccine doesn’t exist. It’s been really good; we’ve identified this early, we’ve changed the vaccine to address this risk, and we’re constantly assessing the benefits versus the risks – and it’s very clear at the moment the benefits far outweigh the risks.
Is it natural for the community to be worried, though?
At this stage, the vaccine is still very effective, especially when you compare it to the small risk, and this risk, while significant, remains very rare, and we’re still talking about less than once per 100,000 people vaccinated.
Talk to me in simple terms, if you can, about what’s happening with this immune response we’re getting in these cases
We’re still looking into what’s driving this – it does appear to be an immune response that’s causing that, potentially one against a clotting cell … so there are some antiplatelet antibodies involved. Still, there’s lots of good work to work out exactly what’s causing this.
What we’d like to see is a way of knowing who’s at risk and not subjecting them to this vaccine, and maybe using an alternate in those people if we can identify it.
Now, the occurrence (of clotting) at the moment is being assessed at one in 150,000 -170,000 people?
That’s exactly right, and what that means is it’s extremely rare – so the vast majority of people won’t get this very rare side effect and of the people who do and we’re now talking of around 11 cases.
While in our country right now, the risk of getting COVID-19 is very low, that might not be the case forever. But also, the risk of not getting vaccinated includes our need to rely on things like border restrictions and lockdowns to keep the virus at bay – so if we get enough people vaccinated, we won’t need to use those measures as much.
Could we talk a bit about underlying health problems and the extent to which that could make you more at risk of clotting, such as if you’re overweight, a smoker or if you’re on the pill?
While they all might be risk factors from traditional clots, which you might get while you are flying or after an operation, they don’t seem to be risk factors for this rare, unusual clotting syndrome.”
What about the family history – we’re hearing people say, “Oh, my mum had a blood clot problem”, does that put that person at greater risk?
No, again, that’s a risk factor for traditional clotting, not for this rare clotting syndrome that’s likely associated with the vaccine.
What about the comparison with Deep Vein Thrombosis? We know people are saying this has happened to me after a long-haul flight. Are those people right to be concerned?
I think they’re right to ask the question, but again … this is a really rare, unusual clotting syndrome, so those kinds of deep vein thrombosis are very common, but it’s a very different process to this one that we’re concerned about.
And is there anything we can do to reduce the risk of (the clotting) from happening?
Not at the moment, a lot of good work is happening to see if we can predict who might be of higher risk, but at the moment, we don’t know of any way to change that.
And what are the symptoms (of blood clotting) that we should be aware of?
The main symptom occurs not in the first day or (second day) where we do expect things like a headache or some aches and pains. It typically occurs between (the fourth and 20th day) and involves more significant pain or discomfort.
Can you ask your GP, for example, if ‘I don’t want to have the AstraZeneca, can I wait for the Pfizer?’
That’s a bit tricky at the moment because we still have issues with that Pfizer vaccine and we’re still using that in a prioritised manner, so if people are genuinely concerned, I’d encourage them to discuss with their GP or vaccine provider.
So what do you say to people who say “I’m going to wait”?
I understand that there’s some concerns … at the moment we’ve heard so much about these events, but what we know is that the vaccine remains very effective and while there are some risks, the benefits of this vaccine still far outweigh those risks.
Is there an urgency about getting the vaccine as soon as possible?
While we know the risk of severe complications from COVID is very low, that’s unlikely to be the case forever, and in the age group who are recommending this vaccine, the complications from COVID infection are very significant.