The effect of monkeypox on the skin – the disfiguring rashes – and flu-like symptoms have been well described, but few have studied the neurological and psychiatric problems the virus could cause.
There are historical reports of neurological complications in people infected with the related smallpox virus and in people vaccinated against smallpox, which contains the related vaccinia virus. So my colleagues and I wanted to know if monkeypox causes similar problems.
We looked at all the evidence prior to the current monkeypox pandemic of neurological or psychiatric problems in people with a monkeypox infection. The results are published in the journal eClinicalMedicine.
A small but substantial percentage of people (2% to 3%) with monkeypox have become seriously ill and have developed severe neurological problems, including seizures and encephalitis (inflammation of the brain that can cause long-term disability). We also found that the confusion occurred in a similar number of people. It is important to note, however, that these figures are based on some studies with few participants.
In addition to severe and rare brain problems, we found evidence of a larger group of people with monkeypox who had more common neurological symptoms including headaches, body aches, and fatigue. From examining the studies, it was not clear how severe these symptoms were and how long they lasted. It was also unclear how many people with monkeypox had psychiatric problems – such as anxiety and depression – as few studies have looked at it. Of those who did, low moods were frequently reported.
We don’t know what factors are driving these neuropsychiatric problems in people with monkeypox. We would like to know if the monkeypox virus strain and the severity of the infection affect these issues. However, we were unable to properly examine it because it has not been consistently reported in studies.
Although we have found that people with monkeypox infection can have neuropsychiatric symptoms, the studies in our article cannot say for sure that the virus is causing these problems. Future research exploring this will need to follow people without neuropsychiatric conditions before they become infected with monkeypox.
If the virus is causing these problems, the underlying biological processes are unclear and could involve the virus entering the nervous system directly, a reaction from the immune system, or something else. It is also possible that the stigma that people experience due to monkeypox infection and the effect of disfiguring rashes can contribute to psychological distress such as low mood.
Our research focused on evidence prior to the current monkeypox pandemic. Most of the data came from West Africa and from people hospitalized for an infection, while the current pandemic has predominantly affected North America and Western Europe. It is unclear to what extent the symptoms of the previous outbreaks will mirror what we are seeing now.
Supported by other recent studies
Important research has emerged since we finished our article. A study in the New England Journal of Medicine included more than 500 people with monkeypox from 16 countries in the current outbreak. Although no cases of encephalitis or seizures have been reported, headaches and fatigue have been found in more than a quarter of people infected with monkeypox and depressed mood in up to one in ten people.
However, there have been two recently reported cases of monkeypox confirmed encephalitis in Spain. Further surveillance is needed to determine the true extent of more serious problems such as encephalitis and seizures.
The monkeypox outbreak remains a global concern and ongoing public health measures are needed, including improving access to vaccination.
Although monkeypox primarily causes flu-like symptoms and skin problems, our latest study – and subsequent studies – show that neuropsychiatric symptoms are not uncommon. We don’t expect a flood of serious brain problems, but complications like encephalitis and seizures can occur in a small percentage of people. We need more research to find out if these symptoms persist over time and if they are caused by monkeypox.
This article was republished by The Conversation under a Creative Commons license. Read the original article.
James Brunton Badenoch does not work, consult, own stock or receive funding from any company or organization that would benefit from this article and has not disclosed any relevant affiliations beyond their academic appointment.