How deadly is monkeypox?what scientists know

A global monkeypox outbreak has caused some deaths, but the death rate is lower than expected from historical data, and scientists breathe a cautious sigh of relief. Of the more than 57,000 confirmed cases, at least 22 have died, a mortality rate of approximately 0.04%. This is significantly less than the 1-3% reported during outbreaks caused by similar strains in West Africa over the past few decades.

All of this has led researchers to reevaluate what they thought they knew about severe monkeypox.

In reality, the true mortality rate will almost certainly be higher than current estimates. Some countries around the world, including Africa, may not have accounted for all deaths during this outbreak due to limited testing and surveillance resources. And it could rise further, especially if the virus spreads more widely among people at high risk of severe illness, such as children, the elderly and those with severely compromised immune systems, he said. epidemiologist Andrea McCallum, who leads the poxvirus team at Centers for Disease Control and Prevention in Atlanta, Georgia.

Still, for the communities most affected so far — young and middle-aged men who have sex with men — the disease is “extremely painful” and “causes a lot of suffering,” he said. disease expert Jason Zucker. -A sick physician at Columbia University in New York City who has treated people with monkeypox. Pain arises from the characteristic fluid-filled lesions that the disease causes. While some have been hospitalized for life-threatening complications, such as breathing difficulties or brain swelling, Zucker says people are more commonly hospitalized for pain management.

Clinicians overall have fewer lesions in the current outbreak than in previous outbreaks in Africa. However, a higher percentage of lesions appear in mucosal tissues of the body. Previously, lesions appeared mainly on the skin: on the hands, feet and face of a person. Although mucosal lesions are less serious in nature, they can aggravate sensitive tissues and cause so much pain that they can interfere with swallowing, eating and drinking in the throat and preventing urination and bowel movements in the genitals and rectum, Zucker said. increase.

These lesions are more difficult to identify and characterize than cutaneous lesions. This means that the World Health Organization (WHO) recommended monkeypox severity scale, which uses the number of lesions as a proxy for disease severity, may need fine-tuning. , he says McCollum.

serious consequences

So far, monkeypox deaths have occurred in at least 10 countries, including Brazil, India, Nigeria and Spain. Efforts are underway to understand how the virus contributed to these deaths.

Some of those who died, including one in the United States and Mexico, were severely immunocompromised and had serious illnesses other than monkeypox. (These deaths have not yet been recognized as monkeypox-related by WHO.)

The two who died in Spain developed encephalitis or brain swelling and had no other known risk factors. Based on previous monkeypox data, these deaths are “certainly alarming, but not entirely surprising,” McCollum said. Encephalitis is a rare but serious complication of many viral diseases, including those caused by herpes simplex and West Nile virus, and is known to occur in infected otherwise healthy people. It is not yet known whether monkeypox encephalitis occurs as a result of the virus infecting brain tissue or because of an overactive immune response that causes swelling of the brain.

Researchers have also seen seizures and encephalitis in monkeypox patients during previous outbreaks: A review of past monkeypox literature published Sept. 8 found that 3% of the 1,512 people analyzed Severe neurological symptoms were found in less than¹.

“It’s not enough to think of monkeypox as a skin or respiratory disease,” says Jonathan Rogers, a neuropsychiatrist at University College London, who co-authored the analysis. The monkeypox virus may have evolved from past outbreaks, but scientists are also learning new things about it because the population currently affected is more broad and geographically diverse.

Who is most at risk?

More research is needed to understand who is most at risk of developing severe monkeypox and which routes of transmission are most dangerous, McCollum said. After an outbreak in the United States in 2003, when rodents shipped from Ghana spread the virus to pet prairie dogs in Illinois, infecting more than 70 people, researchers found that routes of exposure contributed to the severity of the disease. I noticed that the degrees are different.²People who were scratched or bitten by an infected animal tended to have more severe symptoms than those who were exposed to droplets or particles from the animal.

While most transmission in the current outbreak is through close sexual contact, McCollum says the body site the virus first infects (whether skin tissue or mucosal tissue) may determine the severity of the disease. said.

More data are needed to understand whether the effects of severe cases of monkeypox can persist after the infection clears, Zucker said.in their analysis¹Rogers and his colleagues noted that it was common to see scarring at sites of previous lesions. It can also cause inflammation by constricting body tubes such as

“It’s a reminder that this is not a mild illness,” says McCallum. “It can get pretty serious.”