Doctors Say A 'Cytokine Storm' Might Be Why Some COVID-19 Patients Crash : Shots - Health News An overblown immune response could be killing a portion of the sick, and some doctors think that new treatments being tested could help at least some of those patients.

Why Some COVID-19 Patients Crash: The Body's Immune System Might Be To Blame

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Some people who get COVID-19 will experience something that's really frightening. They fight through the first week of the disease and maybe they even start to feel a little bit better. But then suddenly, they crash. They end up in intensive care. And sometimes, they even end up dead. NPR's Geoff Brumfiel explains what's going on here.

GEOFF BRUMFIEL, BYLINE: Right now, the best weapon you have to fight against COVID-19 is your own immune system. The majority of people who get the disease just need to rest while their immune cells seek and destroy the virus. But that army of cells can do collateral damage.

JESSICA HAMERMAN: And when they deal with infection, they make a lot of toxic molecules. And so those toxic molecules can cause a lot of tissue damage.

BRUMFIEL: Jessica Hamerman is an immunologist at the Benaroya Research Institute in Seattle. She says the fevers, aches and pains you feel when you're sick, that's often a side effect of the immune system's work. And sometimes, when the fight is particularly tough, the side effects can get really out of hand. What happens is this - immune cells have a way of calling in reinforcements using molecules called cytokines. And sometimes, cells just keep producing more and more cytokines. Hamerman imagines it this way - the virus is like a fire breaking out in a large building. The cytokines are like the alarm.

HAMERMAN: It's like the smoke alarm never turns off. And you keep having firefighters, like, coming, coming, coming.

BRUMFIEL: Spraying water on the walls, chopping through doors, doing all kinds of damage to the building even if the fire is out. The name for this is a cytokine storm, and it can be deadly. In fact, it's believed that cytokine storms killed a lot of young and healthy people during the flu pandemic in 1918. Now, Hamerman and other scientists and doctors say they're seeing signs storms are killing people infected with coronavirus.

Tests are showing elevated levels of cytokine molecules in the blood of some of the sickest patients, often in the second week, when the immune system is ramped up to fight. Some doctors are trying to treat these storms. One is Daniel Griffin, the chief of infectious disease for ProHEALTH Care Associates, a group of physicians that serves the New York City area. When I spoke to him last week, he had just started using steroids and powerful anti-inflammatory drugs on a handful of patients. The goal was to try and turn down the immune system's alarm. And he said he was seeing results.

DANIEL GRIFFIN: Everyone did really well. It was actually - I have to admit, yesterday was a good day.

BRUMFIEL: Some patients recovered in a matter of hours.

GRIFFIN: The impact was dramatic.

BRUMFIEL: Since then, he's treated dozens of COVID patients. Not all have responded well, but he says, overall, he thinks it's definitely helping. However, Tobias Hohl of Memorial Sloan Kettering in New York City warns that these therapies carry risks.

TOBIAS HOHL: One risk is that the infection could get worse.

BRUMFIEL: Remember, the immune system is the best weapon people have to fight COVID-19. Turning off even part of its communications network just when it's in the fight of its life against coronavirus could cause the virus to surge back. Hohl says the treatment could also lead to secondary infections that could be worse than COVID-19 itself.

HOHL: You know, I don't want to be a Debbie Downer. But I think we have to be humble and just not assume that things are going to work.

BRUMFIEL: Given the dangers, Hohl says, rigorous studies need to be conducted to see who will benefit from the drugs to block cytokine storms. Those studies are already underway.

Geoff Brumfiel, NPR News.

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