(CNN) – Of tens of thousands of monkeypox cases worldwide this year, there have been a dozen virus-related deaths, and for the first time, some of them have occurred outside of Africa, in countries where the virus is not generally spread.
More than 31,000 cases of monkeypox have been reported worldwide since January 1, including more than 10,000 in the United States. Most people have recovered at home with no lasting problems. But doctors are struggling to understand why monkeypox can be serious and, rarely, fatal.
According to the latest figures from the World Health Organization, there have been two deaths from monkeypox in Spain, one in Brazil, one in Ecuador and one in India – all of which are said to be non-endemic countries. So far, none of these deaths have occurred in the United States.
In a recent social media Q&A, Dr Rosamund Lewis, Technical Lead Monkeypox Response for WHO, said the lack of a clear understanding of disease severity is one of the reasons infectious diseases are so difficult.
“When people are exposed to infectious agents, they react in different ways,” she said. Some will develop no symptoms or only mild problems like a mild fever. They get better and go on with their lives. Others, however, develop very serious complications. “We see it now,” she said.
Lewis says the WHO has asked each country for more information about the circumstances surrounding any monkeypox deaths.
Two previously healthy men die in Spain
Two recent cases in particular have sounded the alarm.
A report by Dr Isabel Jado, director of Spain’s National Institute of Microbiology, says the two deaths in that country involved men aged 44 and 31. Their cases do not appear to be linked. The men did not know each other and were not from the same region. Before contracting monkeypox, they were healthy, with no underlying risk factors for serious illness such as a weakened immune system.
Both men developed encephalitis, or brain swelling, which can be triggered by viral infections. They eventually fell into a coma and died.
Andrea McCollum, epidemiologist and smallpox virus expert at the US Centers for Disease Control and Prevention, says encephalitis is a very rare disease known to be associated with monkeypox. It was reported in people with monkeypox in West Africa and in a patient in the United States in 2003 during a small outbreak linked to imported prairie dogs.
“We don’t know why some of these patients have encephalitis,” McCollum told CNN.
The severity of monkeypox likely depends on a person’s underlying health condition, the health care resources they have access to, and the strain of virus that infects them.
In the Congo Basin in central Africa, says McCollum, about 11% of monkeypox cases are fatal, largely because the population has not been vaccinated even against the related smallpox virus, which is believed to protect against monkeypox.
In West Africa, monkeypox becomes fatal about 1% of the time, according to data mainly from Nigeria. It also shows that people who die from monkeypox often have risk factors that reduce their immune function, such as poorly controlled HIV.
Babies are at higher risk for serious consequences because they don’t have a fully functioning immune system, McCollum said. Pregnant women also have reduced immunity and may be at higher risk of monkeypox infection.
The strain of the virus circulating in West Africa – the same strain currently circulating in the United States and other non-endemic countries – is thought to cause milder disease than the Congo Basin strain.
Outside of these endemic settings, not much is known about how and why cases can become severe. Public health officials say they are trying to learn on the fly.
Serious illness, but no deaths, in the United States
A report on the first cases in the United States indicates that of 954 patients for whom information is available, about 1 in 12, or 8%, were hospitalized.
“We are aware that a fair number of patients here have been hospitalized,” McCollum said. Doctors report that some of the complications they treat are urogenital complications or infections that spread to the eyes, “so it’s still a very serious condition,” she said.
McCollum says officials also hear some patients need to be hospitalized for pain management. In other cases, people with risk factors such as reduced immunity are admitted so doctors can monitor them closely.
In one case she recently consulted on, confluent lesions covered an area of the person’s body – “It’s when you have so many lesions, they all merge together.”
This can make the skin so disturbed that it causes problems with fluid loss, and the person must be treated almost like a burn patient until their skin heals.
People most at risk of serious monkeypox infections include: people with advanced HIV, as their immune function may be compromised; pregnant women ; young children and infants; people with eczema or atopic dermatitis because they have many skin lesions that can make the monkeypox rash worse; those with at least one other complication, such as severe nausea and vomiting, diarrhea and dehydration, pneumonia, secondary skin infection; or another disease at the same time
The CDC recommends that people who fall into these groups be considered for antiviral therapies, including an experimental treatment called Tpoxx, which is being given to patients with monkeypox as part of a clinical trial.
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For the latest news on monkeypox, visit the CDC’s website here.
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