Dr Norman Swan, Physician and Journalist

So here’s the latest on vaccines. And I’m recording this towards the end of July 2020, just in case we haven’t updated, so you knew at what time I’ve actually said this. So at the time of talking to you, there’s probably 200 vaccines being developed.

Safety of vaccines

There are a few that have gone through what are called Phase I trials, which are safety trials of the vaccine itself. And I don’t think any vaccine has fallen over yet at the Phase I level. So they’ve all shown to be safe in their own right. But that’s a very different question from safety in the long term in the real world.

Side effects of vaccines

And those vaccines that have come through that period have actually now gotta go into what’s called Phase III trials, where they now think they know what the dose of the vaccine is, and they’re giving it to tens of thousands of people because there could be serious side effects just in 1 in 10,000 people. So if you’ve done a small safety trial with a couple of hundred people, Phase I, you will not pick up the 1 in 10,000. And some of those safety issues may arise when somebody’s confronted with the virus itself. That’s what happened with SARS one. There’s a long way to go. And there are a couple of very promising candidates. There’s one called an MRNA vaccine from a company called Moderna in the United States. That’s going on quite well, but they’ve still got to report on their Phase III study as we speak. There’s a very good vaccine from Oxford University. When I say there’s a very good vaccine, it’s showing good immune responses, which are the sort of immune responses that you need to see to get longer-lasting immunity. So it’s too early to say at the moment. It’s still a 50/50 chance that there’s gonna be a vaccine by 2021.

Access to coronavirus vaccines

And the other issue for Australia is countries are buying up vaccines, even before they’ve been developed, by the bucket load, by hundreds of millions of doses. And we in Australia gotta make sure that we have access to these vaccines. ‘Cause there could be a vaccine and we can’t get it. So that’s a serious issue that we’re going to have to confront.

How good will immunity be from a vaccine?

The other question people ask me about vaccines is that they’ve heard stories of how immunity wanes quite quickly in people who’ve had COVID-19. Well, that’s not necessarily a worry, because if you’ve had a viral infection of any kind, the antibodies do wane with time. They don’t stay up because you’ve not got the virus anymore for it to fight. The key question is whether your body has the memory of that viral infection, so the next time it comes around, it can produce the antibodies almost on demand. And the Oxford University vaccine in particular has the signs that the immune memory may well have been formed. That’s the key thing. Can you kickstart the antibodies when it’s needed to? The other question is how long does that immune memory last? And it could be that it’s only about a year, and therefore we’re gonna need annual injections. It could be that these new vaccines, the first generation of these vaccines are only about 50% effective, just like the flu vaccine. That’s better than we’ve got now, no vaccine at all. And it may be that you need two or three booster shots to actually get effective immunity. So don’t have high expectations that the first round of vaccines are going to be super effective, but they’ll be better than nothing.

Last Reviewed: 29/07/2020

myDr

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