Bad flu is nearly twice as likely to leave you with long-term brain damage than severe Covid, suggests new study

The long-lasting symptoms of flu are more likely to be debilitating and severe than that of long Covid, a new study suggests.

Researchers at the University of Michigan found patients who’d be hospitalized for flu were far more likely to seek medical care for certain conditions than those who’d had hospital treatment for a Covid-19 infection.

Scientists looked specifically at treatment for problems that have been linked to both infections, such as migraine, movement disorders and nerve problems.  

They found those who were hospitalized for flu were nearly twice as likely to receive treatment for a neurological disorder in the following year, compared to their Covid patient counterparts.

For instance, the flu group were 44 percent more likely to seek treatment for nerve pain, and 35 percent more likely to need help for persistent migraines.

They were also up to ten percent more likely to receive treatment for a stroke or dementia.

The scientists said that their analysis, which involved 77,000 patients, said their findings were ‘reassuring’ because it showed Covid was not more likely to cause complications than other diseases.

Dr Adam de Havenon, a neurologist at Yale University, Connecticut, who was involved in the research, said: ‘Since Covid has now infected the majority of adults in the US, it’s good news that it behaves similarly to other respiratory viruses with respect to common neurological conditions.

‘There was concern that the already limited access to neurological care would further shrink if we had a dramatic increase in neurologic care after Covid infection.’ 

Both Covid and influenza infections raise inflammation in the blood, which can damage blood vessels thoughout the body, including the brain — leading to a range of complications.

The two respiratory viruses are also known to cause complications like encephalitis — swelling of the brain — and Guillain-Barre syndrome, an autoimmune disorder affecting peripheral nerves.

The results may cause contention among some doctors who are skeptical about the severity of the condition, after $45million was awarded in grants to treat long Covid patients.

Long Covid is a poorly defined illness which is notoriously difficult to diagnose as the symptoms can easily be mistaken for signs of other conditions. 

Patients who have the syndrome complain of a wide variety of symptoms including persistent fatigue, muscle pain and brain fog which drag on for months after their Covid infection.

Studies have found it is far less likely to occur in those who’ve been vaccinated against the infection, even if they contract it. 

Long flu is a similar poorly-defined condition, also encompassing people suffering from a wide range of complications for weeks after their infection.

The study, published in the journal Neurology, scientists reviewed the medical records of 77,200 people who were hospitalized with Covid between March 2020 and November 2021, as well as a group of patients hospitalized with flu before 2020.

Patients were 51 years old on average, six in ten were female and four in ten were from white ethnic backgrounds.

Scientists checked the medical records of patients for up to a year after their hospitalization to see if they’d received medical treatment for six common neurological disorders.

These were migraines, epilepsy, stroke, neuropathy, movement disorders and dementia.

After adjusting for factors including age and sex, results showed that long flu patients were more likely to suffer from all six of the conditions in the year after their hospitalization.

Nearly five percent of long flu patients received care for the conditions, compared to 2.79 percent for those with long Covid. 

Patients with long flu were also 36 percent more likely to receive treatment for a movement disorder, 22 percent more likely to receive treatment for epilepsy, 10 percent more likely to receive treatment for a stroke and seven percent more likely to receive treatment for dementia.

Dr Brian Callaghan, the neurologist who led the research, said: ‘It’s important to note that our study did not look at long Covid outcomes, and our results do not necessarily conflict with the findings in other research showing an increase in neurologic symptoms in people with long Covid.

‘While the results were not what we expected to find, they are reassuring in that we found being hospitalized with Covid did not lead to more care for common neurological conditions when compared to being hospitalized with influenza.’