The emergence of new COVID variants out of the UK and South Africa have raised alarm bells across the globe.
It doesn’t come as a surprise that a virus that’s spread to tens of millions of people would change over time.
These variations occur on a spectrum. While a new variant can mean nothing important changes at all, a new variant can also mean that our vaccines don’t work and that treatment for infection is completely different.
Let’s take a look at what these new variants mean.
Why do new variants form?
Changes in a virus are the result of mutations in its genetic sequence. Every time the virus replicates, there is the possibility of a random genetic change if the RNA strand is not perfectly copied.
The reason that I suggested it’s not a surprise that we have new variants developing is that SARS-CoV-2 is everywhere.
When so many people are infected, we should essentially expect that genetic variation is going to happen.
Although coronaviruses in general (and SARS-CoV-2 in particular) have excellent replication fidelity, it’s more likely than not that the trillions of replication cycles across tens of millions of people are going to have a couple of variations occur.
So the emergence of new variants isn’t odd, it’s just what happens when a virus is this successful in spreading.
This is literally evolution in action
This process - random chance leading to genetic variants - is how evolution happens. Whether a new variant sticks around is going to be determined by whether the variant has success in reproducing (i.e. infecting us). If a new variant is more effective in reproducing over time, it’s going to outcompete other variants and take over.
This is what the term “survival of the fittest” means in the most purely evolutionary sense.
Is the new UK variant bad?
The short answer is yes. It’s very bad.
Here’s the longer answer.
With any new variant, we need to think about 3 major factors:
Virulence or pathogenicity - is a new variant more likely to make you really sick or kill you?
Transmissibility - how easily is the virus spread from one person to another?
Response to acquired immunity from prior infection and vaccines - does previous COVID infection protected against the new strain? And will our vaccines work against this new B117 variant?
A new variant doesn’t necessarily mean that anything changes with any of these factors, but when a new variant is produced that spreads more easily, it can very quickly overtake any other variants.
In fact, we already saw this phenomenon happen early in the pandemic when the “more highly fit” D614 variant overtook the G614 variant (responsible for the origins of the COVID-19 pandemic) worldwide. The D614 variant was more easily transmissible than the G614 variant - likely related to higher viral loads present in the upper respiratory tract of infected people - but there was no difference in virulence.
The new B117 variant that emerged from the UK appears to have increased transmissibility without any change in virulence.
So this new COVID strain spreads more easily but doesn’t cause more severe disease.
Increased transmissibility is much worse than increased virulence
My first instinct when I heard about the new UK strain of SARS-CoV-2 was to wonder about how sick you would get if infected with the new strain. Intuitively, the virulence of a new strain seems like it should be the most important factor in determining the impact. It feels like a virus that makes you sicker should be a bigger deal than a virus that spreads more easily.
Unfortunately, this isn’t the case.
A more contagious virus promises to pour gasoline on the spreading fire of our current pandemic of unchecked COVID spread. Even small changes in the transmissibility can make a much bigger difference in deaths than changes in virulence:
“Take a virus reproduction rate of about 1.1 and an infection fatality risk of 0.8 percent and imagine 10,000 active infections—a plausible scenario for many European cities, as Kucharski notes. As things stand, with those numbers, we’d expect 129 deaths in a month. If the fatality rate increased by 50 percent, that would lead to 193 deaths. In contrast, a 50 percent increase in transmissibility would lead to a whopping 978 deaths in just one month—assuming, in both scenarios, a six-day infection-generation time.”
A variant that leads to increased spread means the potential for exponential growth in the number of cases, hospitalizations, and deaths.
This is bad
On a societal level, exponential growth of a new COVID variant means many more cases and many more deaths. This variant is already in the US and spreading here. That means our case numbers, which have already been awful, are probably going to get even worse soon.
This is obviously terrible.
We haven’t yet fully unpacked why the virus is so much more contagious, so we don’t know yet how it’s able to spread more easily.
This difference is probably due to a change of infectivity. It may require fewer virus particles to cause an active infection. Or it may be better able to invade our initial immune response and make us sick. Or some other mechanism entirely.
It’s important to note, however, that this remains a respiratory virus, so the mechanism of transmission is likely to be the same. That means the same precautions that we’ve been taking - masks, physical distancing, hand washing, ventilation - should continue to be applicable.
Is there any silver lining?
Yes, there certainly is.
First, if you get the new variant, you probably aren’t more likely to get very sick or die. This is (sort of) good news (for any one individual)!
Second, and probably more importantly, it seems likely that our vaccines will protect against this new variant.
What’s the bottom line?
We should be alarmed.
This is the time to take extra precautions against contracting COVID.
When you combine the uneven (to put it mildly) vaccine roll out, nationally uncontrolled community spread, and a new strain that appears significantly more infectious, it’s much more likely that things get worse before they get better. Possibly much worse.
From a personal perspective, this news makes me more cautious in terms of taking non-medical precautions and that’s the advice I’m giving my patients - be more vigilant about the usual stuff you should be doing already.
When it comes to dealing with viral spread during a pandemic, an appropriate public health response feels like overkill (and creates societal backlash against restrictions) in hindsight, and a “proportional” response in the moment quickly demonstrates its inadequacy as time unfolds.
I think that we’re all dealing with COVID fatigue to a certain extent. And so I get the the reluctance of public health officials - and the mistrust that many of our leaders have earned from their communication thus far - to communicate clearly about the potential risks posed by this new variant. That doesn’t change my level of worry.
I anticipate many of you will read this post and conclude that I’m becoming overly alarmist. You might be right! And it would be great if you are.
I hope that I can look back on this writing in a month or two and wonder how I was so wildly wrong in my predictions about the dangers of the new UK COVID strain.
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