The global outbreak of monkeypox and linked vaccination campaign could lead to a spate of neurological issues like nerve pain, seizures, brain inflammation and mood disorders like anxiety and depression, a group of scientists warned in a review of research published Tuesday in JAMA Neurology, urging further research into the poorly understood disease as the number of new cases in the U.S. falls.
Issues like nerve pain, seizures, encephalitis—brain inflammation—and mood disturbances, including anxiety and depression, are well-documented complications of infections with viruses like smallpox that are closely related to monkeypox, researchers said in the peer reviewed paper.
While few major neurological issues have been reported during the global monkeypox outbreak, the researchers warned that similar “complications are to be expected” in monkeypox patients and urged clinicians to be vigilant.
Those with compromised immune systems, such as some people living with HIV or AIDS, are particularly at risk as the monkeypox virus may be able to persist in the body for longer or more able to invade the nervous system, the researchers said.
Given the large number of people now receiving monkeypox vaccines to curb the outbreak, clinicians should also be on the lookout for neurological complications from the shots, the researchers added.
Older vaccines used against smallpox, which could also be used against monkeypox, utilize another related virus, vaccinia, to provoke immunity and are associated with a suite of well-documented, potentially serious side effects.
Though newer and safer than previous vaccines—as well as using an inactivated, rather than live, virus—the researchers said clinicians should remain vigilant of any adverse reactions to the Jynneos vaccine being used in monkeypox campaigns.
Though scientists have known about monkeypox for decades, the disease has largely been ignored by the world and caused limited, sporadic outbreaks in parts of Africa. Past outbreaks suggested the virus does not transmit easily between people but experts have long feared it had the potential to one day spread and fill the void left behind after smallpox was eradicated. It appeared nearly simultaneously in several countries where it does not normally spread earlier this year and cases were not linked to travel in affected regions. The discovery suggested monkeypox had been spreading undetected for some time, probably years, and the scope, scale, geographic range, speed and demography of the outbreak set it apart from previous flare ups, which have usually been relatively confined and burned themselves out. Growing data from the outbreak, which has predominantly affected men who have sex with men, indicates the virus is almost exclusively spreading through sex between men and has a different set of symptoms than in previous outbreaks.
62,406. That’s how many confirmed cases of monkeypox there have been around the world this year as of September 14, according to the CDC. More than a third of these, nearly 24,000, have been recorded in the U.S., which has the most confirmed cases by far. Monkeypox cases in the U.S. and Europe have been trending down in recent weeks, though it is unclear whether the drop is due to vaccination or changing behaviors in response to the outbreak.
By Robert Hart, Forbes Staff