New research on the epidemiologic and genomic evolution of the clade 1b mpox outbreak in the Democratic Republic of the Congo (DRC) suggests 83% of cases were linked to sex work, three healthcare workers contracted the disease, and infected pregnant women frequently miscarried.
Marion Koopmans, DVM, PhD, of Erasmus University in the Netherlands, and her colleagues published these findings yesterday in Nature Medicine.
In related news, New York state officials have confirmed clade 1b in a resident, the first such case in New York state and the fourth clade 1b case confirmed in the United States.
The observations from the Koopmans group involved patients at the Kamituga hospital in South Kivu, DRC, which saw its first clade 1b mpox case in September 2023. From September 2023 to June 2024, 670 mpox case-patients were admitted to the hospital from 17 surrounding health areas. Of the cases, 52.4% were in females, and 47.6% in males.
The researchers collected samples from the patients and data on where patients lived and possible exposures.
During the study period, seven deaths from mpox were noted among hospitalized patients, and three healthcare workers contracted the disease. Four of the seven deaths occurred in young adults, ages 20 to 30 years. Also of note, 14 patients were pregnant women, among whom 8 reported miscarriages after contracting mpox.
Unlike other clusters in the DRC, only 15.5% of case-patients seen at Kamituga hospital were under the age of 15 years. Of those 104 patients, only 45 were less than 5 years of age.
Overall, 83.4% of cases were linked to sex work, often linked to bars, with case-patients reporting transactional sex with both men and women. Genetic analysis showed three distinct clusters of viruses, all clade 1b, but no links between bars or health areas were observed.
These data suggest rapid spread mostly through sexual contact within densely populated areas.
"These data suggest rapid spread mostly through sexual contact within densely populated areas," the authors said. "Spread to neighboring countries highlights the need for extended cross-border collaboration, health education strategies focusing on sex workers, contact tracing, clinical care and surveillance."
Since 2023, the DRC has reported more than 50,000 suspected mpox cases in an outbreak that has spilled over to neighboring countries. Most cases are clade 1b, which is highly transmissible and more virulent than the clade 2 virus, that caused a global outbreak primarily among men who have sex with men in 2022.
Today Reuters reported that New York state has its first case of clade 1b mpox. According to the news agency, the patient is in isolation and was diagnosed after a recent trip to East Africa.
The Centers for Disease Control and Prevention (CDC) has confirmed the case, the fourth clade 1b in the United States. All US cases have been travel related and are not linked, the CDC said.