Let’s talk about coronavirus herd immunity, which is something that is being tossed about by everyone, including the British Prime Minister. I guess until the point that Boris Johnson contracted COVID-19.
Herd immunity is one of those terms in public health that is misunderstood and misused by people who are on all sides of science from vaccine deniers to vaccine advocates.
But there’s one thing we should remind ourselves – coronavirus herd immunity is no panacea, and it probably won’t happen without a COVID-19 vaccine, which is probably years away. Furthermore, pandemics like COVID-19 are almost impossible to predict – that makes it even more difficult to determine if we can even have herd immunity for this disease.
What is coronavirus herd immunity?
In epidemiology, herd immunity is the concept that describes the state where a population is sufficiently immune to an infectious disease, like coronavirus, so that the infection will not spread within that population. In other words, enough people can’t get the disease – either through vaccination or natural immunity – that the people who are vulnerable are protected.
Depending on the virus’s basic reproduction rate (the infamous R0), the predicted herd immunity rate varies between viruses.
The herd immunity threshold is lower as the R0 is lower. Thus, the coronavirus herd immunity threshold may vary from 29-74%, which is a large range. Right now, predicting the R0 for COVID-19 has been difficult, especially since testing for the disease has been lackluster in many countries like the USA. To be safe, and to protect the vulnerable from the disease, we will probably have to be at the upper range of that
When I first heard of herd immunity being applied to COVID-19, I thought that it was just one of those random ideas that have been run up the flagpole and quickly dismissed. I kind of chuckled when I read it, because anti-vaxxers, who in the Venn diagram of science deniers overlap COVID-19 deniers, have long claimed that herd immunity is fake.
One thing I’ve long known about all anti-science wingnuts, whether creationists, climate change deniers, or anti-vaxxers, they have moving goalposts. Anti-vaxxers hate herd immunity when we need it for vaccines, but love it when they want to get rid of public health efforts in response to the current pandemic.
And now, we’ve got people, both on the left and right, who think that we should consider achieving coronavirus herd immunity by just letting people contract the disease. They consider it our best preventative strategy to stall the flood of COVID-19 cases.
Let’s consider this dangerous response.
What’s wrong with coronavirus herd immunity?
We really should not consider herd immunity as a preventative measure, unless it’s in context with a widespread coronavirus vaccination effort. And, as I’ve discussed a lot, that’s not going to happen in the next few months. It’s going to take years.
So what are the reasons we should not consider “natural coronavirus herd immunity” by allowing 70% of the population to contract the disease – most of these claims center around reaching that 70% goal by allowing young people to contract the disease?
That’s absurd, and here’s why:
- Young people can die of the disease. Despite these tropes that young people are somehow resistant to the disease, in New York City, around 3.9% of the deaths attributed to COVID-19 were in ages 19-44. And 2-4% of those aged 20-44 in the USA required treatment in the intensive care unit (ICU).
- Unless we build a wall around every person in the USA with comorbidities like age, chronic diseases, or tobacco smoking, it would be impossible to prevent the disease from killing those people. A coronavirus herd immunity attempt would be, in fact, genocide for a large group of people across the world.
- There are still known and unknown long-term effects of coronavirus on people of all ages who have ostensibly recovered from the disease. It might cause long-term and dangerous harm to the lungs, brain-stem, and other systems.
- Around 10% of people across all age groups need to be hospitalized because of COVID-19. That can overwhelm the healthcare system, causing much more economic harm than mitigation efforts.
- If we assume that 70% is the coronavirus herd immunity level, that means around 200 million people in the USA would need to be infected. If 1% of them die, do the simple math – that means a catastrophic 2 million people would be dead.
- We have no clue if the immunity to the disease is short- or long-term. What if it lasts only a few months, and some evidence supports that some people are susceptible to COVID-19 re-infection. This is a big worry to vaccine experts with regards to the rush for a new vaccine.
- We have no clue if the virus will mutate. There is some disputed evidence that the virus has already mutated. And many coronaviruses do mutate regularly. If it mutates to a more virulent form, then we’d have to restart herd immunity with potentially greater than 2 million deaths in the USA alone.
Unless we’re going to be emotionally cold about this, the only way to have coronavirus herd immunity is to sacrifice huge swaths of people across all age groups. Now some people might think that getting rid of “boomers” is a good idea, many are a powerful part of the economy. And it’s just disgusting to want to kill off people for any reason!
The only way to have coronavirus herd immunity is with a vaccine. And that’s not going to happen for years, despite the wild claims of people like Donald Trump who thinks that watching a movie about an Army physician who creates a vaccine against a deadly virus within a week is a documentary about how to get a vaccine really fast.
This herd immunity delusion is probably impossible to achieve without genocide. We need a safe and effective vaccine (which we aren’t close to having) to build real and lasting coronavirus herd immunity. What we need is to listen to leaders who make science-based decisions about how to carefully move forward with the world economy without sacrifice our fellow humans.
For right now, many leaders are ignoring the advice from scientists, putting all of us at risk of this deadly disease. It makes me sad.
Update 29 May 2020
New evidence has been published that shows that we’re a long way from coronavirus herd immunity. An article published in the New York Times provided a visually striking view of the low number of people who are actually “immune” from the disease.
Based on their research, we probably need around 60% of the population immune to the disease before we reach herd immunity. But even in cities like New York, which has been devastated by the disease, only about 20% of the population is immune. That means that COVID-19 can still spread quickly.
And the New York Times states that:
Some countries — notably Sweden, and briefly Britain — have experimented with limited lockdowns in an effort to build up immunity in their populations. But even in these places, recent studies indicate that no more than 7 to 17 percent of people have been infected so far.
COVID-19 deniers frequently use Sweden as their example of how the rest of us can keep our economies going and get herd immunity to protect everyone. That isn’t supported by any evidence whatsoever.
And to reiterate the points I’ve made before, creating coronavirus herd immunity without a vaccine is genocide:
If you assume that herd protection could be achieved when 60 percent of the population becomes resistant to the virus, that means New York City is only one-third of the way there. And, so far, nearly 250 of every 100,000 city residents has died. New York City still has millions of residents vulnerable to catching and spreading this disease, and tens of thousands more who are at risk of dying.
That means tens of thousands of more deaths just in one city. The worldwide mortality rate from this disease just to get “herd immunity” would be catastrophic. Furthermore, there is more and more evidence that the disease kills poor people and certain ethnic groups more than whites with good healthcare coverage. (This is another point about Sweden – despite the fact that they have a higher mortality rate from COVID-19 than most other countries, they actually have an excellent healthcare system which actually can save lives.)
For anyone who believes that we are nearing herd immunity, and we don’t need a vaccine, you’re just plain wrong. Without a vaccine, this pandemic will kill a lot more people over the next few months or years.
- Riou J, Althaus CL. Pattern of early human-to-human transmission of Wuhan 2019 novel coronavirus (2019-nCoV), December 2019 to January 2020. Euro Surveill. 2020 Jan;25(4). doi: 10.2807/1560-7917.ES.2020.25.4.2000058. PubMed PMID: 32019669; PubMed Central PMCID: PMC7001239.