Health Experts Are Watching a More Dangerous Version of Mpox

WInfections with a new group of mpox viruses are rising, potentially posing a risk to people around the world, according to health officials at the U.S. Centers for Disease Control and Prevention (CDC).

So far, cases have been concentrated in the Democratic Republic of Congo (DRC) and have not spread beyond Central African countries, where the virus remains endemic, the CDC wrote in a statement. report on May 16th. But health officials are concerned because this group of viruses — known as clade I mpox viruses — is known to cause more severe illness than the clade II viruses responsible for previous 2021 mpox outbreaks, which originated in Nigeria. Clade I mpox viruses have a higher mortality rate – killing between 1.4% and more than 10% of infected people – than clade II, which has a mortality rate of 0.1% to 3.6%. %.

The 2022 outbreaks spread primarily through sexual contact between men who have sex with men. An effective two-dose vaccine helped protect these highest-risk groups and prevented infections from turning into an epidemic. (The current vaccine also works against newer subtype I viruses.)

But with the recent increase in global travel, health authorities are keeping an eye on the spread of the latest subtype I viruses outside the regions where they are endemic. According to the CDC report, health authorities in the DRC reported that subtype I infections were reported in 25 of the country’s 26 provinces and that young people were hit hardest: 67% of cases and 78% of deaths occurred in people aged 15 or over. younger. The virus can cause more serious illness in people with weakened or compromised immune systems.

Researchers believe the infections were caused by exposure to infected animals, which then spread quickly from person to person through close contact within households.

see more information: What it really feels like to have Mpox

In the US, the CDC recommends that doctors test anyone suspected of having mpox, whether due to recent travel to affected areas in Africa, contact with someone who has recently been to Africa, or exposure to someone with mpox. Symptoms include fever, headache, rash and painful sores. Existing tests for mpox are designed to detect orthopoxviruses, the group of viruses to which mpox (and smallpox) belong, but these tests cannot detect whether an infection belongs to clade I or II.. Some tests available at specific labs can detect clade II viruses and therefore rule out clade I mpox, but to be sure, the CDC is conducting additional genetic analysis on positive orthopox samples sent from U.S. labs to the agency to determine that type of virus it is. .

No clade I cases have yet been found in the US According to the CDC, 343 samples tested positive for orthopox from December 2023 to mid-April 2024, and additional testing showed no clade I virus. To better capture any potential infections among people who may not be tested, the agency also began looking for mpox last December in wastewater and, so far, the positive signals correspond to areas where clade II viruses have been found. Samples collected at four airports through the CDC’s Traveler-Based Genomic Surveillance program from passengers who volunteered to provide samples have not detected any orthopox viruses since last December.

For now, the CDC is working with health authorities in the DRC to monitor and respond to the current outbreak in that country. The effective vaccines that most of the world turned to in response to the 2022 outbreaks are not authorized in the DRC, which increases the risk that cases will continue to rise and potentially spread beyond that region of the world.

In the US, the agency urges doctors to educate their at-risk patients, who include gay and bisexual men and men who have sex with men, to get the vaccine. Since the 2022 outbreaks, only 23% of people at risk for mpox infection in the US have received two doses. “Collaboration among global health partners is now urgently needed to assist the DRC in acquiring and distributing sufficient vaccines where they are needed most,” CDC scientists write in the report.