Don’t pin all our hopes on a vaccine
This opinion piece was published by The Age on 23 August.
By Professor Eric Morand, from Monash University's School of Clinical Sciences at Monash Health and Dr Samar Ojaimi, Infectious Diseases expert from Monash Health.
Research is crucial when we are rapidly learning the virus can turn the immune system into an enemy.
Most experts think a vaccine against COVID-19 is likely to become widely available by mid-2021. The federal government has made an in-principle deal with at least one potential vaccine manufacturer, of the so-called Oxford vaccine, to ensure delivery to Australians if candidates being developed here don’t pan out.
However, even with the most optimistic expectations, it will probably be years before universal vaccination and a return to what we hope will be a new normal more like the old. Even with universal vaccination, the disease itself is not likely to be beaten, at least not yet.
SARS-CoV-2, the virus that causes COVID-19, has proven an indefatigable foe, and the reality is that the new normal will be accompanied by a spectrum of associated symptoms in thousands, even millions. We are rapidly learning this virus doesn’t just cause pneumonia or blood clots; it can cause a person’s immune system to overreact in such a way that it becomes an enemy within.
For many of us in some fields of medicine, the battle with this enemy is strangely familiar. When a virus or other micro-organism infects a person, their immune system is activated. In some people, however, the immune system is revved up without the trigger of a viral invader. The resulting ‘‘autoinflammation’’ is the cause of diseases such as rheumatoid arthritis, multiple sclerosis and juvenile diabetes.
One of the consequences we are increasingly hearing about is the cytokine storm. As rheumatologists and immunologists, specialists in systemic immune-inflammatory diseases, we have known about the harmful effects of cytokines for decades. Cytokines are molecules that immune cells use to communicate with other cells, passing on messages such as ‘‘I found a virus’’.
The severe inflammation in the lungs known as acute respiratory disease syndrome, which has become a hallmark of COVID-19, has long been associated with a cytokine storm, or hyperstimulation of the immune system that results in a tsunami of inflammation.
Rheumatologists and immunologists have long used drugs that block cytokines to treat autoimmune and autoinflammatory diseases. Now we are trialling them against COVID-19, including against the severe lung problems but also other symptoms of COVID-19 that may also be due to cytokine excess. The New York Times recently cited a preliminary report of the anti-viral drug remdesivir, which appeared to modestly accelerate recovery in COVID-19 patients. But the really sick patients did not respond to the drug, and Dr Chaz Langelier, from the University of California, suggested in the article that it might be the immune system, not the virus, driving the disease in these instances.
Almost all severe COVID-19 symptoms could be explained by raging inflammation: the damage in the lungs, the thickening of blood vessel walls causing heart attacks and strokes, the neurological damage causing fatigue and sensory/cognitive issues.
This is why much of the treatment focus on COVID-19 complications has been on immune-modulating drugs such as the steroid dexamethasone, ensuring that the patient’s immune system overactivation doesn’t cause destruction of healthy tissue and cells.
One reason why finding cures or treatments for autoimmune diseases has been so difficult is because finding ways to stop the immune system from hurting its own host – the patient – is a balancing act. You can’t dampen down the immune system without making the patient vulnerable to further viral and bacterial infections.
However, experience in immune disease with modern cytokine-blocking drugs, which are developed to have a laser focus on individual cytokine molecules, has been far less risky than once feared, suggesting a way forward for treating the cytokine storm of COVID-19.
So while clinicians globally are trying different immune modulators in the ICU to save patients’ lives, and larger clinical trials are testing these drugs in a more controlled setting, we need to keep working to understand what is happening at the immune cell level.
Today, HIV has been effectively beaten 40 years after it first appeared – not with a vaccine but through development of targeted cocktails of drugs, all of which required a deep understanding of how and why that virus was so successful in infecting the immune system.
Gloves, vaccines, safe distancing and lockdowns may be what we are focusing on now but we shouldn’t lose sight that knowing the enemy, through basic research, is ultimately what will help us conquer this.
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For more information on Professor Eric Morand, view his research profile.