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This episode was filmed on January 19th, 2022.

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[♪ INTRO]

Throughout the COVID-19 pandemic we’ve 
seen new variants of concern of SARS-CoV-2,

the virus that causes COVID-19.

The World Health Organization gives 
names to new versions of the virus

that it determines might have more of an 
impact on people, say by spreading more easily,

causing more severe disease, or being better 
at getting around our body’s defenses.

The latest variant making headlines is Omicron.

It was first identified in late November of 2021.

But as is always the case with this pandemic, 
we’re still trying to learn about its effects,

and what this new variant means for 
the overall course of the pandemic.

Here’s what we know right now.

Omicron is spreading quickly, and many experts 
predict it will overtake the Delta variant

as the dominant variant of SARS-CoV-2 worldwide.

You or your loved ones might have already 
been affected by it, given its rapid spread.

Part of the reason for the rapid spread is 
that this version of the virus appears to be

more infectious, meaning more likely to spread 
from person to person, than previous ones.

For example, data from the UK and Denmark 
suggest that Omicron is more likely than Delta

to spread within a household, even in 
cases where all members of that household

had been vaccinated and received booster shots.

The Danish study is a preprint, meaning 
it has not been published or peer reviewed

but has been uploaded to a pre-publication server.

There’s no guarantee these preprints are correct,

as they haven’t been through the 
usual process of scientific scrutiny,

but they are a way to share potentially 
important information quickly.

We’ll be talking about a few 
other such studies today.

With that out of the way, the reason for 
the heightened infectiousness might be

because Omicron is more adept at dodging the 
antibody defenses that vaccines give us.

Take one lab study, published in the journal 
Cell, which looked at people who had been fully,

recently vaccinated with either the 
Moderna or Pfizer/BioNTech mRNA vaccines,

or the Janssen viral vector vaccine.

Half the people who had been 
fully vaccinated, but not boosted,

couldn’t mount an immune defense against Omicron.

On top of that, preprint data out of 
South Africa suggests previous infection

with a different variant of the virus also 
provides little immunity against Omicron.

It also showed that people can 
become infected more than once.

However, other preprint data 
suggest that the Janssen vaccine

does provide protection against hospitalization, 
so this one might need more time to untangle.

Why? Well, most of these papers focused on 
the neutralizing antibodies our immune system

produces in response to a vaccine or the virus, 
but that’s not all our immune system does.

So the vaccines may be helping our immune 
systems protect us from Omicron in other ways.

Like the variants that came before 
it, Omicron has a number of mutations

compared to earlier versions, including 
many that affect its spike protein.

These may make it better at both infecting cells, 
and avoiding antibodies that target the spike.

It also seems to affect different parts 
of the body compared to previous variants.

Preprints from Hong Kong and the UK have 
found that it’s up to 70 times better

at replicating in the nose or upper airway than 
Delta, which hangs out more in the lungs.

More virus particles in the nose and throat 
could mean it’s easier to sneeze or cough it out

and help the virus spread.

Hanging out in the upper airway could also be why

this variant seems to cause less severe disease.

This also may be why the reported symptoms 
of Omicron are slightly different:

more runny noses and sore 
throats, and more ear aches,

because everything is congested up here.

Now, there seem to be fewer hospitalizations 
around the world for Omicron than Delta,

especially for vaccinated individuals.

And when those hospitalizations do happen, 
people tend to stay in the hospital for around

70% less time regardless of vaccination status,

according to one preprint 
study out of California.

Plus, a British report from December 2021 
found that the risk of being hospitalized

because of an Omicron infection was 
around a third of the risk for Delta.

This was a pretty small study, though, so take 
the numbers with a statistical grain of salt.

But – and this is a big but – the number of 
hospitalizations is going up. And quickly.

There’s still going to be a subset 
of people who become seriously ill,

even if the variant is milder.

So if case numbers are high, that still represents 
a large overall number of people who will need

hospital care, and who may develop the group 
of long-term symptoms known as long COVID.

The question on a lot of people’s 
minds now is what Omicron means

for the future of the pandemic.

One of the big questions is 
how the virus will evolve.

As in, whether we’ll keep seeing not just new 
variants, but new variants that are dangerous.

Researchers have warned that as the virus 
continues to spread around the world unchecked,

that creates opportunities for new mutations 
that might turn into a variant of concern.

So slowing transmission is as 
important as it’s ever been.

Fortunately, we’re not back to square 1.

We know far more about this 
virus than we did in early 2020.

We know that non-pharmaceutical public 
health interventions like social distancing,

limiting the number of people in enclosed spaces,

and testing and tracing policies will 
continue to play a role in our response.

Some people have predicted that 
COVID-19 will become an endemic disease.

That is, one where the disease is 
always present in the community

and causing infections on some level.

However, many other experts point out that that’s 
not a good outcome, whether or not it’s likely.

Seasonal flu is an example of an endemic disease

that still comes with a 
significant death toll every year.

Endemism is also slightly different from herd 
immunity, which you may have heard discussed.

That’s where most people have immunity 
and the disease can only spread

within particular sub-populations 
who aren’t immune.

And that’s something that experts 
were never really banking on,

despite public figures talking it up.

Because this virus is just too good at 
shifting into new forms for the defenses

we get from vaccines, or prior 
infection, to completely wall it off.

It’s different from, say, measles, 
where vaccination is effective

at preventing disease in most people.

But vaccination will still be a valuable tool.

Expanding vaccination to as many people 
as possible worldwide will give the virus

fewer opportunities to mutate into new 
variants, as overall infections decline.

Plus, some scientists are using data 
from all of the known previous variants

to try to build predictive models 
of what might be around the corner.

A recent study in Science Translational 
Medicine looked at what mutations have helped

a particular virus variant spread in the past.

The researchers analyzed what features 
of that mutation helped it spread,

and developed a computer model that they used to

retroactively predict which mutations 
have spread up to four months in advance.

Now they hope to use the model as a starting point

to help us prepare or screen for new variants.

So when it comes to Omicron, 
we’re not reliving March 2020.

But there are also still lots of unknowns, 
and this is still a dangerous virus.

So stay safe, everybody.

And if that’s enough news for you for one day, 
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Brilliant’s math courses include their 
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It presents an intuitive, 
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If you check them out, you’ll see how much work 
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Even better, if you check them 
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premium subscription to Brilliant. So thanks!

[♪ OUTRO]