A potentially more dangerous variant of the mpox virus is rapidly spreading in several countries, with the first case reported outside Africa this week in Sweden.
As anxiety grows over this strain linked to more severe illness, infectious disease specialists remain cautiously optimistic that it might not proliferate widely in the U.S. or have a serious impact.
Factors such as immunization from vaccines and past infections from earlier outbreaks, the lack of viral presence in wildlife, and better healthcare access might help limit the risk of this mpox subtype in the U.S.
The World Health Organization recently reinstated mpox (formerly known as monkeypox) as a public health emergency due to a significant outbreak in the Democratic Republic of Congo that is also affecting other nations.
Dr. Boghuma Titanji from Emory University noted that it was inevitable for the virus to spread beyond Africa, as Sweden reported its first case outside the continent.
In a statement, Dr. Pamela Rendi-Wagner, head of the European Centre for Disease Prevention and Control, raised the risk level of the mpox variant to “low” for the general European population, citing strong connections between Africa and Europe.
To date, the CDC has confirmed no cases of this variant in the U.S.
This new strain is generally seen as more transmissible and severe compared to another variant that drove a global outbreak peaking in August 2022, which had a death rate of 0.2%. Those most at risk from the previous variant, particularly individuals with advanced, untreated HIV, faced a higher likelihood of severe outcomes. Currently, clade II remains low-level in the U.S.
Dr. Anne Rimoin from UCLA emphasized the importance of context, stating that claims about increased danger must be carefully assessed, as data on severity and mortality is still limited.
Research by the National Institutes of Health indicated that a treatment did not significantly reduce symptom duration for the new strain, but the mortality rate was better than expected, suggesting improved medical care for patients.
Dr. Jennifer McQuiston from the CDC sees this data as encouraging, believing that high-quality healthcare in the U.S. would reduce fatalities related to the disease.
While Dr. Dan Barouch of Harvard anticipates the U.S. will see some cases, he noted that the immediate risk remains low.
The CDC has been alerting healthcare providers since December to watch for this new variant and has updated its guidelines. Testing for mpox now includes checks for specific clade types.
McQuiston added that the agency is especially concerned about this strain compared to the previous one. The Jynneos vaccine seems effective against both types, although only a quarter of those at risk in the U.S. are fully vaccinated.
Most cases in the Democratic Republic of Congo primarily involve sexual transmission but have also affected children significantly.
Recent mutations in the virus may enhance transmissibility, yet extensive close contact usually remains necessary for the spread, which is less common in the U.S. due to living conditions.
In the DRC, inadequate access to vaccines and cramped living conditions pose significant risks that limit the spread in the U.S.
Differences in sexual behavior patterns could also curtail broader outbreaks, with studies suggesting many people have developed natural immunity from past infections.
However, questions remain about how protection from earlier variants holds up against new strains, highlighting the need for vigilance as the situation evolves.
Dr. Chloe Orkin from Queen Mary University noted that it’s unclear how immunity from previous strains will affect susceptibility to this new one.
In conclusion, while experts are cautiously optimistic, there is a need for ongoing monitoring and a proactive approach to prevent potential outbreaks.