In spring 1918 a new virus started to sweep the word. Called the “Spanish influence” because, at the height of the war, Spain was the only country not cooking their books and thus it looked like it started there, it killed more people than the war. (It’s more likely that it started at a U.S. army base).
The Spanish flu had one unusual and hideous property. It killed an unusual number of the young and healthy. Generally, those vulnerable to flu are the young (who’s immune systems haven’t developed fully) and the old (who have immune systems that have weakened over time).
The Spanish flu killed a lot of young adults. At the time, this was mysterious. Was it caused by all the soldiers still moving around? One theory is that the Spanish flu was particularly prone to causing something called a “cytokine storm.”
Which is also a feature of COVID-19. So, perhaps we should explore what a cytokine storm actually is.
What is a Cytokine Storm?
Cytokine storms are a known complication of influenza and other respiratory diseases.
Our immune system produces a number of proteins that coordinate the body’s response. These proteins, called cytokines, help tell the killer cells in our immune system where to go and what to do. They’re kind of the traffic lights.
A cytokine storm happens when the body’s cytokine production goes out of control. Way too many cytokines are released. They then activate too many immune cells, which start attacking healthy tissue.
All of your traffic lights go to red.
Fever spikes, blood pressure drops (not a good thing when you have a virus that, in at least some cases, increases clotting. Organ damage ensues.
Sometimes, people die.
The cytokine storm caused by COVID-19 appears to be concentrated in the lungs, and often happens as the person appears to be getting better.
Stopping the cytokine storm is a key piece of reducing overall mortality from COVID-19, especially in younger patients. It may also explain some of the weird patterns with this disease — genetics determine your risk of a cytokine storm.
How do you Stop a Cytokine Storm?
So, how do you stop a cytokine storm? Paradoxically, this may mean suppressing the patient’s immune system.
Unfortunately, one of the normal ways of detecting a cytokine storm, elevated levels of serum ferritin, may not be as good for COVID patients. The elevated levels are caused by how the storm affects the liver, and the cytokine storm triggered by COVID does not appear to affect the liver as much.
The ultimate answer is drugs, but we need to identify drugs that are specifically good to stop the cytokine storm caused by COVID-19. A number are being tested. If you’ve been wondering why drugs used to treat rheumatoid arthritis are being investigated, this is why.
Steroids can also help with this situation, and it’s possible that the steroid dexamethasone, which is being shown to reduce mortality in the most seriously ill patients, works in part by reducing cytokine production.
Steroids, however, also suppress other parts of the immune system, which might not be helpful when fighting off a virus.
Stopping cytokine storms is part of the complicated COVID-19 puzzle. (Don’t expect one sudden breakthrough treatment to solve everything. It’s not going to work that way). We have a lot of work to do here; and a lot of smart people doing it.