A detailed analysis of monkeypox files released Friday by the U.S. Centers for Disease Control and Prevention offers new insight into the outbreak, which is disproportionately affecting men who have sex with men, especially those who are black and Hispanic.
There were 2,891 cases of monkeypox reported in the United States as of July 22, about two months after the country’s first case was reported. In 41% of those cases, case forms with additional epidemiological and clinical information were submitted to the CDC, although not all details in all of those forms were complete.
Of the cases with available data, 94% were in men who reported recent sexual or close intimate contact with another man. More than half (54%) of the cases were among black and Hispanic people, a group that represents about a third (34%) of the general US population. And the proportion of cases among black people has grown in recent weeks, according to the CDC analysis.
“Public health efforts should prioritize gay, bisexual and other men who have sex with men, who are currently disproportionately affected, for prevention and testing, while addressing equality, minimizing stigma and maintaining vigilance for transmission in other populations,” the report authors say.
Additional analysis shows that all patients had rash. However, a genital rash was reported more frequently in the current outbreak than in “typical” monkeypox. It was the most common site for a rash (46%), followed by arms (40%), face (38%) and legs (37%). More than a third of cases with available data reported rashes in four or more regions.
However, early warning signs of disease are less common in the current outbreak compared to “typical” monkeypox. In about 2 in 5 cases, the disease started with the rash – but no prodromal symptoms such as chills, headache or malaise were reported. About 2 in 5 cases also reported no fever.
The report’s authors emphasize that anyone with a rash consistent with monkey pox should be tested for the virus, regardless of their sexual or gender identity or the presence of other symptoms.
Of the cases for which data were available, less than 1 in 10 (8%) required hospitalization for monkeypox. No deaths were reported.
Of those for whom vaccination status was available, 14% had received a smallpox vaccine, including 3% who had received one dose of Jynneos during this outbreak. At least one person with monkeypox had symptoms more than three weeks after their first dose of the Jynneos vaccine.
A “significant proportion” of monkeypox cases have been reported in people with HIV, who may be at higher risk for serious illness. More analysis of this group is underway, according to the CDC.
The agency says it is “constantly evaluating new evidence and adjusting response strategies as information on changing demographics, clinical features, transmission and vaccine effectiveness becomes available.”