Grim effects of long Covid amplify need for vaccine

New evidence from the Covid-19 pandemic paints a grim picture of the long-term neurological effects of the disease and further emphasises the importance of protecting our population through vaccination.

In The Lancet Psychiatry, researchers from Oxford and Cambridge analysed data from an extensive electronic health records network of more than 81 million patients. The researchers identified 236,379 recovered Covid-19 patients and compared their rates of 14 neurological and mental health disorders with those diagnosed with influenza or a respiratory tract infection that wasn't Covid-19-related.

The study revealed that at least 33 percent of survivors experienced some degree of neuropsychiatric conditions such as anxiety, depression and even brain haemorrhage in the six-month timeframe after contracting the virus. The researchers also indicated that 13 percent of patients received these diagnoses for the first time. Interestingly, even young people with mild symptoms or asymptomatic can suffer from "long Covid". Compared to patients with influenza, Covid-19 patients were 44 percent more likely to experience neuropsychiatric illness in the six months after contracting the virus.

The most common neuropsychiatric illnesses in recovered patients were on the ''milder'' side -17.4 percent experienced an anxiety disorder; 13.7 percent a mood disorder; substance abuse disorders were evident in 7 percent and insomnia in 5 percent. On the other hand, 2.1 percent experienced an ischemic stroke, and 0.7 percent were diagnosed with dementia. This rate increased among patients who had to be admitted to an intensive care unit, where 7 percent experienced an ischemic stroke, and 1.7 percent experienced dementia.

The current cause of long Covid is still unknown, but initial results indicate the virus causes an inflammatory cascade reaction that damages the blood vessels in the brain (see research by University of Auckland neuroscientist Dr Helen Murray). In people suffering from long Covid, the immune response is activated but unable to turn itself off. This chronic, aberrant response is likely the cause of fatigue and viral-type symptoms, but the other symptoms are harder to explain.

The researchers also investigated initial alarming reports of the autoimmune disorder Guillain-Barré syndrome and Parkinson's disease in Covid-19 survivors. It became apparent that the number of survivors with these conditions was not increased when compared to the influenza group (Parkinson's disease 0.11 percent, Guillain-Barré 0.08 percent).

However, given these disorders can take years to manifest, the six-month time period survivors were studied was not long enough to see the full impact of Covid-19 on these disorders.

What is unsettling though is the almost twofold increase in dementia in patients with Covid-19 compared to patients with influenza in this short timeframe. The increase is worse for people over 65 years (2.7 percent). Some of this increase is explained by people with Covid receiving better follow-up. Secondly, patients admitted to ICU have generally worse outcomes, and as more people with Covid end up in ICU, this increase is not that surprising.

However, additional analysis solely on Covid-19 survivors that were not hospitalised also revealed an increase in dementia. This is a disturbing finding when we take the total number of Covid-19 cases globally into account (more than 150 million).

Two smaller UK-based studies, unpublished and not yet peer-reviewed but available as preprints, confirm ongoing symptoms in Covid-19 survivors. Both studies demonstrate that most patients (71-93 percent) did not feel recovered five to seven months after the initial infection. These studies indicate that middle-aged women hospitalised with the disease have a higher risk of ongoing long Covid symptoms. Sex-based differences in the immune response could be responsible for the higher occurrence of long Covid in women.

What is becoming clear is the long-term effects of this disease are concerning, and the neurological impacts could be long-lasting. In New Zealand, we have an opportunity to avoid these effects on our nation's health by implementing a successful vaccination campaign. Vaccination will protect against the acute effects of Covid-19 and ensure our population won't have an increased risk of long-term, life-changing neuropsychiatric disorders.