We still don’t know how Covid-19 kills us, and that raises a big red flag for doctors trying to treat critically-ill patients.

Online science publication Nature says that scientists are not sure “whether the virus itself” is what kills us, or whether our immune system’s response is so strong that it “ultimately overwhelms the patient’s organs”.

This puts doctors in a frustrating dilemma in an emergency situation.

If they reach for drugs that “dampen the immune response”, these drugs could also “undermine the body’s own fight against the coronavirus”.

Such drugs would include steroids which “act broadly to suppress the immune system” in general.

“My greatest fear is that this gets taken to an extreme, where people are using whatever they can get their hands on to turn off the immune response,” Daniel Chen, an American immunologist told Nature. “You can’t knock down the immune system at a time when it’s battling an infection.”

Researchers say clinical data suggests that the immune system “is playing its part in the decline and death of people” infected with the virus, but this doesn’t make steroids the silver bullet for managing it.

Also, this plays into the virus’s strongest weapon at the moment: we just don’t know enough about it to battle it properly.

According to Nature, “As coronavirus patients flood hospitals worldwide, physicians are wading through streams of incomplete data ... that have not been peer-reviewed.”

This means they’re “struggling to find ways to help their patients” and are “sharing experiences on social media”. 

Some doctors are even “trying cocktails of unproven therapies in a desperate bid to save lives”.

“People are watching patients deteriorate before their eyes, and there’s a very strong motivation to reach for any therapy that you think could be effective,” Kenneth Baillie, an intensive-care anaesthetist at the University of Edinburgh told Nature. “When I feel powerless at the end of a bed, I feel the same.”

Rafi Ahmen, an immunologist in Georgia in the US, explains that some viruses affect you immediately and in that case, it is “likely the virus itself” that has made you sick in a type of “hit and run” way.

But, with viruses in which symptoms only appear a few days later, like Covid-19, it is likely that the body has been fighting the disease but adding to its damaging effects at the same time.

Simply put, “collateral damage from the immune response often contributes to the illness,” says Ahmen.

In the absence of an answer, Ahmed and other specialists are, according to Nature, “hopeful that researchers will arrive at a combination therapy that does not completely suppress the immune system, combined with an antiviral drug that directly targets the virus”.

In the meantime, according to Baillie, it is crucial to collect data wherever steroids are being used.

“There’s no other way to know if a treatment is working,” he says.