What’s the deal with Omicron?


First detected in South Africa in November 2021, it’s quickly becoming the dominant strain of SARS-CoV-2 (aka coronavirus)  in the world. Here‘s a primer.

What’s different about Omicron?


Compared to the original strain of the virus, Omicron has around 50 mutations. Of these, 30 are on the spike protein. Ten are on a key protein called the ACE2 receptor which makes Omicron more likely to infect people. It also replicates itself in the body faster than previous versions, so we become infectious to others sooner after infection ourselves, so within 1-2 days after exposure. It is spreading very quickly in Australia and likely to take over as the dominant (most common) strain here, although that doesn’t mean Delta will automatically disappear.

Is Omicron milder than previous variants?

The experts have their fingers crossed, but are saying it’s too soon to tell. Early signs from South Africa are that a smaller percentage of infected people needed hospital care with Omicron, and those who did stayed for a shorter time and were less likely to progress to ICU.

There are a couple of factors that might complicate the issue though. Prior to Omicron, around 70% of the South African population had experience with defending itself against either COVID-19 through prior infection or vaccination, so those stats may reflect better immunity against severe disease rather than less dangerous virus itself. (Australia has about 81% of it’s total population with some degree of immunity through infection or vaccination).

We also don’t know how an ageing population might affect these stats. The average age in South Africa is 27.6 years, whereas in Australia it’s 37 years.

Will being double vaccinated or having a previous COVID-19 infection stop you getting it?

Maybe, maybe not.

Because Omicron has so many mutations, it’s better at avoiding our antibodies, which are the first lines of defence against infection. Both reinfections and breakthrough infections (where you’re infected after being  vaccinated) are more common with Omicron.

For example, two doses of Pfizer protects against around 33% of infections from Omicron compared to 70% of the older strains. Protection from two doses of AstraZeneca is potentially even lower. The further you get past the second dose, the lower your protection from infection.

So was getting double vaxxed a total waste of time?

No. Because the immune system is complex, the other parts that kick in once it detects an infection has occurred kick into gear. These deeper immune responses are likely to protect you against severe disease from both Delta and Omicron for around 5-6 months after your second dose. The purpose of vaccination remains the same with - reduce likelihood of you being infected, getting sick and ending up in a hospital bed a more vulnerable person needs.

Ok, so 5-6 months before the protection against severe disease wanes. Is this why they’re talking about boosters?

Spot on. If you look at your kids’ immunisation records, you’d see most diseases are a three dose course to get that deep immune response optimally primed. What we’re thinking of as “boosters” are more like third doses, and they bring that waning antibody immunity right back up as well as more deeply rooting in your complex immune response strategies.

Current advice in Australia is for a third dose 5 months after your second dose. If you’re immunocompromised that time frame is 2 months after your second dose.

Does it matter which vax I get as the third dose?

The mRNA vaccines are the better ones for third doses (so Pfizer or Moderna), but if there’s a contraindication (medical reason) you can’t have those you can get a third Astra Zeneca.

Moderna’s third dose faired slightly better in its clinical trial than Pfizer, but only by a couple of percentage points. The current recommendation is to go with whichever is available to you and/or recommended by your health team as soon as you’re eligible for it.

All 3 are considered safe for people who are pregnant (at any stage of pregnancy), lactating and trying to conceive.

What about Omicron in kids under 5?

Given they can’t get vaccinated yet, it’s a question on a lot of parents’ minds. There was an early concern that more 0-4 year olds with Omicron were ending up in hospital in South Africa than previous waves. With further investigation it was found that more children already in hospital for other reasons were testing positive, and their Omicron symptoms were mostly mild. Hopefully this trend continues as vaccines for this age group are unlikely to be available until mid-2022.

The Health Minister in NSW, Brad Hazzard, said we could see 25 000 cases a day in January. If we don’t know how serious Omicron is yet, why are we letting it rip?

I believe what you are seeing in action is what happens when economists decide public health policy, rather than public health experts. To do away with social distancing/lockdowns, density limits, masks at most indoor venues and QR codes while many vulnerable Australians have not had their third doses, at peak travel time of year, and while Omicron is taking off is unlikely to go well.

Even if a  tiny proportion of adults (say 1-2% of these) need hospital care that is still a LOT of people needing care at 25 000 cases a day. When you consider positive cases and need for sick leave/close contact isolation amongst the hospital staff population, we’re in real strife.

Translate this to day care and school settings, disability and aged care environments, food supply/transport chains, face to face services in post offices, banks etc. it’s not going to be pretty, particularly with hardly any disaster support payment options for people meant to be isolating and businesses.

A capitalist, individualist culture means “care work” is devalued in favour of “productive” industries, forgetting they are reliant on that care. It also puts the impetus for “taking care of yourself” on the individuals while providing an environment where it’s near impossible to do so, then scolding them for being irresponsible.

It’s dangerous and lazy on the part of our politicians. I realise we can’t live locked down forever, but I do think this could be done more sustainably with more care for human life. Look after each other as best you can, because in my opinion, the state and federal political leaders are definitely not doing it.


This piece was put together after listening to a month straight of ABC CoronaCast with Dr Norman Swan, reading up on ATAGI and RANZCOG recommendations, and learning from various actual doctors and actual science educators on Instagram, namely @thewholesomedoctor @deplatformdisease @dr.risahoshino and @pandemicpregnancyguide

It is general in nature and not intended to replace medical advice or conversations with your own medical practitioners.