Covid side effects spark a warning over a hike in Parkinson’s disease

The Florey institute fears a wave of neurological consequences from COVID-19, including a big escalation in Parkinson’s disease.

Artwork - generic image of head and brain. Silhouette of a man's head with electrical activity.

The nation’s leading institute of neuroscience and mental health, the Florey, is warning of a wave of neurological consequences from COVID-19, including a big escalation in the incidence of Parkinson’s disease.

The neural inflammation that is experienced in many sufferers of COVID-19 is a key risk factor for developing Parkinson’s, it warns.

After the Spanish flu pandemic, there was a tripling in the incidence of Parkinson’s, and The Florey warns the same thing is likely to happen with the COVID-19 pandemic. It’s calling for widespread screening and early treatment to address the feared wave of neurological disease.

Researchers at the Florey have published a paper in the Journal of Parkinson’s Disease warning that the degenerative illness is likely to represent the “third wave of the COVID-19 pandemic”.

They argue that the neurological symptoms of COVID-19, which range from encephalitis to loss of sense of smell, are likely to be under-reported.

The paper’s co-author Leah Beauchamp said it was estimated that three out of four people with COVID-19 experienced neurological symptoms from the virus.

“There’s this concept in Parkinson’s disease called the dual hit hypo­thesis,” said Ms Beauchamp. “Essentially, a person is exposed to a pathogen much like COVID, or a virus. And if it gets into the brain, it triggers a neuro-inflammatory response. And this response essentially primes the brain so that later in life or in over the coming years, if a person then encounters another hit to the brain, whether that be from ageing or from exposure to another virus or another toxin, the brain is primed, and ready to overreact. And that over-reaction leads to cell death.”

Loss of sense of smell is reported in up to three-quarters of COVID-19 cases, and in up to 90 per cent of cases of Parkinson’s disease, 10 years ahead of the development of motor symptoms.

“We believe that loss of smell presents a new way forward in detecting someone’s risk of developing Parkinson’s disease early,” Ms Beauchamp said.

“While on the surface this symptom can appear as little cause for concern, it actually tells us a lot about what’s happening on the inside and that is that there’s acute inflammation in the olfactory ­system responsible for smell.”

Parkinson’s disease affects about 80,000 people in Australia, and its incidence has doubled in the past 20 years. It is forecast to double again by 2040, a situation that could be accelerated by the COVID-19 pandemic, just as with the Spanish flu pandemic.

“We know people born between 1888 and 1924 had a two to threefold increase in the incidence of Parkinson’s disease,” Ms Beauchamp said. “Much like with COVID-19, there were several neurological symptoms involved in the Spanish flu. And within five years, we saw a huge increase in the incidence of Parkinson’s disease. We’re seeing a common trend that we’re concerned is repeating in COVID-19.”

The Florey researchers are calling for the development of a mass screening protocol aimed at identifying people at risk of developing Parkinson’s or who are in the early stages of the disease.

Drug therapies are in development which, if administered early enough, may be able to slow or halt the development of the illness.

Florey researcher Kevin Barnham said the screening protocol might include tests on the sense of smell and vision tests for motor symptoms and brain scans. “We would like to … take the lesson from the Spanish flu and monitor these people over the next few years,” Professor Barnham said.

“The key thing we want to drive home is that we need to change the way we think about Parkinson’s disease, the way we approach diagnosis and treatment.”