Boosters: Yay, nay, when?

If you want the TLDR – head to the bottom of the post.

Firstly, should we call them boosters or the 3rd dose? To me it doesn’t really matter, but I can see why people might get frustrated.

We were told that two doses are fully immunised. And it was at the time. It reduced the chance of contracting COVID-19, but more importantly it significantly reduced the chance of becoming really ill with acute COVID-19.

But time goes on, and we learn more, and life gets more complicated. And so, we find that like with almost every other vaccine ever given – effectiveness wanes over time. The difference is those diseases aren’t in your face every day or evolving with vaccine evading mutations as quickly as this one. So, we don’t really think about it. Out of sight, out of mind.

ATAGI is deliberating if we should change the definition of fully immunised to be 3 doses instead of 2. Cool. Doesn’t matter. Because fewer places have full vaccination as a requirement of entry (or if it is, it’s not as enforced) – though healthcare facilities like hospitals would likely still enforce it for some time.

So why get a 3rd dose? And if you are keen, when should you get it?

Why get a 3rd dose?

Well, as mentioned above immunity seems to wane after the full course of all the COVID vaccines currently available in Australia. Not unexpected, just probably not emphasised at the time. So, a 3rd dose significantly boosts people’s immune response, kind of like a nudge to say, “hey don’t forget about this condition”.

We do it for Hep B in adults, heck kids get 3-4 doses of Hep B, Hib, Pneumococcus, Diphtheria, Tetanus and Polio just to let their immune systems know not to forget these important but infrequent infections.

So, it’s not a new thing.

Even if it isn’t AS protective against Omicron as it was against Delta, Delta still is in the population AND it still improves protection against Omicron. So as long as there’s COVID-19 out there, a 3rd dose is a great way to protect yourself.

When should I get a 3rd dose?

There’s “when can I?” and “when should I?”.

During December and January everyone argued to allow 3rd doses at a shorter interval. If you recall it was 5 months post dose 2, then 4 months and now 3 months.

But now there’s plenty of 3rd dose appointment slots and vaccines available, yet only 48.5% of NSW residents have had their 3rd dose.

Part of the reason is that not everyone is eligible yet – for some people they didn’t get their 2nd dose until recently. Other people have had their 3rd dose delayed by actually being infected with Omicron (or just COVID-19 – they don’t really tell you which one you had). But there are a lot of people out there who are eligible and haven’t had their 3rd dose yet.

But if you are keen to have your 3rd dose, and you are eligible, getting it now is a good idea. You are more likely to contract COVID-19 when case numbers are higher (and compared to pre-omicron, they’re high), and the reported numbers are likely to only be a fraction of the true case load.

There is some talk that winter might be worse – but so far COVID hasn’t really shown a propensity to transmit less in summer and more in winter like other respiratory viruses. It really has stayed fairly strong with waves occurring due to other factors like waning immunity, new variants, dropping nonpharmacological measures like mask wearing.

Or if you are pretty fastidious about wearing a high-quality mask, and staying away from crowds and indoor spaces, and your 2nd dose was less than 5 months ago, you could wait a little if you really wanted – but I’m not sure it gives us much advantage.

Though vaccines are in stock, clinics are pulling out of the immunisation program as it is a LOT of hard work. And state hubs are winding down also. So should there be a spike in demand for vaccines – it might be hard to get one the day you want it. And since it takes up to 2 weeks to build up that immunity again, you want it before a wave, not during.

What if I have had COVID?

If you’ve recently had COVID and you’ve had doses 1 and 2, then you can get dose 3 as soon as you’ve recovered, but you can probably delay it up to 3 months post recovery. There’s some evidence that getting COVID with Omicron doesn’t actually afford you much protection anymore, though Delta did (against Delta).

If you’ve had COVID between doses 1 and 2, get dose 2 as soon as you’re well.

If you’ve had COVID and have NOT had any doses, heck you can definitely get immunised because you really don’t want to catch it again. Each infection carries a risk of severe disease, leaving behind some long-term medical issue, or triggering long COVID (which can occur even in mild cases of acute COVID).

Which vaccine for the 3rd dose?

Right now, the advice is either Pfizer or Moderna for your booster, regardless of which vaccine you had for your first course. The only exception being you could use AstraZeneca if you had that for your first two vaccines, and you are allergic to mRNA vaccines or you insist on AZ. But it seems that getting an mRNA as a booster seems to improve the immune response.

Novavax isn’t currently approved as a booster, but is being researched as part of the PREVENT-19 Phase 3 vaccine trial, where it will be given 6 months after a primary course of Novavax, and also given to people who received a different vaccine for their primary course. So, keep an eye out if this is the vaccine you prefer.

Does this mean we just keep getting boosters?

No. Not in the long run.

A study in Israel where they gave a 4th dose showed that while antibody levels rose, even a little higher than the 3rd dose, but probably still not high enough to stop people getting Omicron.

But it did reduce hospitalisation and severe disease by a factor of 4 times for people aged over 60.

Pfizer itself has said it would prefer that people didn’t have to get boosters every 4-5 months as this would be difficult both in terms of global supply, and as we’ve seen just with a 3rd dose – people are kind of tired of getting vaccines all the time.

The development of newer vaccines that cover a bigger range of variants and may produce a more lasting immune response would be good, such as the influenza vaccine. But given that variants and waves are not seasonal, there will need to be more work done to develop this vaccine.

A pan-coronavirus vaccine is in the works, though the name might be misleading. It doesn’t cover every type of coronavirus (and before COVID-19 there were a lot), but it would try to cover a common thread of all current COVID type illnesses and hopefully SARS and MERS.

So, while there will be an increasing number of vaccines available for COVID-19, it’s not likely we’ll be getting a shot every 3-4 months.

Dr Daniel’s recommendations:

For the TLDR (Too Long, Didn’t Read) people, yes you should get a 3rd dose.

You should get it because it reduces the chance a bit of catching COVID-19, but greatly reduces the chance of being really sick – for an extended period of time compared to not having a 3rd dose.

You should get it now if you’re eligible.

If you’ve recently had COVID and you’ve had doses 1 and 2, then you can get dose 3 as soon as you’ve recovered, but you can probably delay it up to 3 months post recovery. There’s some evidence that getting COVID with Omicron doesn’t actually afford you much protection anymore, though Delta did (against Delta).

But other than vaccines the other stuff really works. Wear a good mask properly when other people are around you, or where they’ve recently been. This means indoors, in lifts, in rooms where someone just was. Wear the best mask you can get your hands on – N95 or KN95. Wear it outside if you’re walking past a lot of people – think of COVID spreading like cigarette smoke – you can often smell it quite far away from the smoker, and you can smell it for a while.

Make sure fresh air is getting to places as best it can. Windows open when you can. Air purifiers with HEPA filters if you can get them.

It’s been 2 years since COVID became a worldwide problem. Yet no one at Green Square Health has contracted it. We’ve vaccinated over 12,000 people. And we did it by doing all the above as much as possible.

We don’t need to be fatalistic – we’re not all going to get COVID. You can take control and reduce your risk as much as you can. When the wave dies down – the risk goes down with it.

As the narrator on Monkey Magic says.


If the world often seems unfair to people who believe in fate, this is because fatalists can come to believe they cannot change or improve. But if there is fate, it is fated that we make our own lives.

Narrator, Monkey Magic