healthHealth and Medicine

Is Calling Omicron “Mild” Misleading?


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer


A word to describe Omicron is starting to take hold in the global psyche: “mild.” But is this really a good way to think about the newest variant of concern? Image credit: Jarun Ontakrai/Shutterstock

After the initial scare, the overall reaction to the emergence of the Omicron variant of COVID-19 has been one of, well, relief. And for apparently good reason: compared to previous variants, Omicron has a lower incidence of hospitalization and death; it doesn’t seem to be able to infect the lungs like its predecessors, and, anecdotally at least, patients with the infection seemed to be getting less sick, recovering faster and easier, and, in many cases, not experiencing symptoms at all.

One word started to take hold in the global psyche: Omicron, people started to announce, is “mild.”


But is this really a good way to think about the newest variant of concern? For many reasons, quite a few people think not – and they are pushing back against the idea that Omicron is a “mild” disease.

Let’s take a look at why.

Omicron is still potentially deadly

Let’s be clear: Omicron may have a lower death rate than previous variants, but it’s still killing people.


According to one report from a South African hospital, the incidence of death for patients admitted with Omicron was less than one in 20 – much lower than the more than one in five who died from previous variants. That sounds good, but to put it into perspective, there are certain types of heart attack that have a better survival rate than one in 20, and it would be a bit weird if we started seeing op-eds calling for the whole country to start having heart attacks all of a sudden.

What’s more, we have to remember we’re looking at this from more than two years into the pandemic. Omicron may be better able to evade our bodies’ defenses than other variants, but vaccines still provide some level of protection – and getting booster shots improves the situation even further. Even in people who can’t or won’t get vaccinated, it looks like surviving a previous COVID-19 infection can boost your immunity for a time (though they are, of course, less likely to survive at all).

That, according to a Harvard Center for Population and Development Studies working paper published last month, makes it “premature to consider Omicron infections to be intrinsically milder than those caused by preceding variants.” Omicron has been unleashed on a population that has significantly higher immunity levels than the one that faced the Delta wave a year earlier, making it impossible to tease out whether Omicron really is less severe, or if our bodies were just more prepared when it arrived.

“The … Omicron variant [came] at a very different stage of the pandemic,” vaccine expert Shabir Madhi of the University of the Witwatersrand told The Guardian back in December. “[The] immunity that currently exists … is different to what existed in the past, and that immunity is going to bring about some change in the clinical course of the infection, including the likelihood of infection progressing to severe disease.”


“That is important to keep at the back of our minds when we see what is unfolding in South Africa and what we might see in other settings, which might have a very different epidemiology.”

And that leads us to something else …

Hospitalizations are actually increasing

We know, it doesn’t sound logical: Omicron has a much lower rate of hospitalization, and yet hospitalizations are up. But it’s true – in fact, this Monday the US saw its highest number ever of hospital admissions for COVID-19 infections: a record 132,646 people.


What’s going on? It’s quite simple: Omicron is really, really, really contagious. To put it bluntly, you may be less likely to be hospitalized if you catch Omicron instead of Delta – but if you have neither, you’re way more likely to catch Omicron.

Omicron and delta
For illustrative purposes only, not based on specific data. Image credit: (C) IFLScience

“The volume of people presenting to our emergency rooms is unlike anything I’ve ever seen before,” Kit Delgado, an emergency physician in Pennsylvania, told The Atlantic.

And some populations are particularly vulnerable. We’re used to thinking of COVID-19 as a disease that largely spares the young, but Omicron is changing that: children, many of whom are still too young to be vaccinated, are being admitted with COVID-19 to hospitals across the US in record numbers.

“This crush of omicron cases in children is causing hospitalizations to surge statewide," Sara Willa Ernst of Houston Public Media told NPR this week. “Here in Houston at Texas Children's Hospital, pediatric COVID hospitalizations have been doubling every week over the past month or so.”


And those children who do contract Omicron can expect a worse time of it than their adult compatriots.

“For kids younger than 12, there aren't a ton of treatment options,” explained Ernst. “They're not eligible for the COVID antiviral pills, which are in really short supply right now, or for monoclonal antibodies that are effective against omicron.”

So thinking of Omicron as a “mild” version of COVID is, at best, slightly misleading: even though Omicron has a much lower rate of hospitalization or death than previous variants, its bananas infection rate more than cancels that out in terms of raw numbers. Population-wise – counting COVID-19 positive and negative people – your chances of getting a severe or fatal case may not actually have gone down.

“A virus that spreads more rapidly, even if milder, could cause much more deaths,” tweeted independent developmental biologist Malgorzata Gasperowicz. Modeling the spread of four hypothetical viruses using a simple mathematical formula, she showed that even a variant 10 times less deadly than the original virus would be more lethal to the population at large if it was also twice as transmissible.


“In 20+ days "Mild & Fast" outpaces Severe & Slow variants in the number of new people it kills,” she wrote.


And how do those hypotheticals stack up against real life? Well, “10 times less deadly” is actually fairly accurate to Omicron’s mortality rate compared to Delta, according to recent data cited by the Centers for Disease Control and Prevention (CDC), but “twice as transmissible” – well, that’s an underestimate.

And that’s a big problem. Because …

Hospitals are in trouble


It’s no secret that healthcare systems across the world have been feeling the strain throughout the pandemic. But with Omicron, the situation is threatening to grow out of control.

“Before, the sickest ICU patient would get two nurses, and now there’s four patients for every nurse,” Megan Brunson, an ICU nurse in Texas, told The Atlantic. “It makes it impossible to do everything you need to do.”

“Our reserves aren’t there,” she added. “We feel like we’re tapped out, and that person who is going to come in to help you isn’t going to, because they’re also tapped out … or they’ve tested positive.”

Statistics bear this out: data from the US Department of Health and Human Services shows that nearly one in four hospitals across the country are currently reporting a “critical staffing shortage.” It’s not just the US: in Britain, hospitals have been calling for military support to help ease the demand on healthcare workers, and Canada has seen entire provinces forced to suspend all non-urgent surgeries to free up space for COVID-19 patients.


This is ironic for two reasons: first, because an overwhelmed healthcare system may itself mask the severity of the Omicron variant – after all, you can’t count as a hospital admission if the hospitals can’t admit you. But even more than that, it gives Omicron a second, less direct weapon: all those other things we’d normally be at the hospital for, but now can’t be.

“At some point ... we're too overwhelmed to do any of our normal daily work,” University of Kansas Health System Chief Medical Officer Dr Steven Stites told CNN. “At that point we have to turn on a switch that says we got to triage the people we can help the most … [we] have to let some people die who we might have been able to help but we weren't sure about — they were too far gone or had too much of an injury, or maybe we can't get to that trauma that just came in.”

What about Long Covid?

Omicron has only been around for a couple of months, but already it seems to have a faster recovery time on average than other variants. But for some unlucky people, a case of COVID-19 can linger for weeks – or even months.


Depending on how you measure it, up to around one in eight people who contract a COVID-19 infection will go on to develop long COVID. We don’t know yet whether the case is the same for the Omicron variant, but according to Dr Anthony Fauci, Chief Medical Advisor to the US President, we should “not expect it’s going to be any different.”

The thing is, when you consider just how many people are getting infected with Omicron, that percentage translates to a mind-boggling number of people set to live (or die) with a long-term debilitating condition.

“I have no idea what’s in store for us as far as long Covid is concerned,” admitted epidemiologist Dr Salim Abdool Karim in a December 2021 webinar on the new variant. “It’s a really important question, and it’s particularly so because Omicron is spreading so fast and so widely so quickly – the number of people getting infected is so big that … if it’s a common consequence of even mild infection, you can imagine, even if in 10% of people, there’s going to be a lot of people with long Covid.”

The Omicron Variant: a “milder” disease?


So is it fair to call Omicron a “milder” disease? It depends. In the absolute strictest sense, yes: “mild,” in its original medical sense, means “less likely to result in hospitalization,” and statistically speaking, Omicron is that.

But does that mean Omicron is not worrying? Definitely not. When we consider just how infectious it is, those lower hospitalization and mortality rates become less significant on the population-wide scale: simply put, so many people are getting infected that even a massively reduced severity is still overwhelming hospitals. And overwhelmed hospitals can’t provide treatment to those who need it – whether they are admitted with COVID, cancer, or something else entirely.

The lesson: don’t underestimate Omicron. It may be less severe, but it’s certainly not, as Republican senator Rand Paul told Fox News, “nature’s vaccine.” What is a vaccine, though, is, well, vaccines – and doctors are urging people to continue taking sensible, medically sound precautions in order to protect themselves against the strain.

“The next few weeks is also about, you know, better getting the message out that the measures that we're familiar with, you know, vaccinating more people, masking and social distancing,” Ernst told NPR. “[That] can really help slow the spread.”


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