A detailed analysis of monkeypox case records released Friday by the US Centers for Disease Control and Prevention offers new insight into the outbreak, which disproportionately affects men who have sex with men, especially blacks and Hispanics.
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. Case report forms with additional epidemiologic and clinical information were submitted to CDC for 41% of those cases, although not all details were complete on all of those forms.
Among 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 occurred among blacks and Hispanics, a group that represents about a third (34%) of the general US population, and the proportion of cases among blacks has increased in the weeks, according to the CDC analysis.
“Public health efforts must prioritize gay, bisexual, and other men who have sex with men, who are currently disproportionately affected, for prevention and testing, while addressing equity, minimizing stigma, and maintaining surveillance of transmission in other populations,” the authors of the report say.
Further analysis shows that all patients had a rash. However, a genital rash was reported more frequently in the current outbreak than in “typical” monkeypox. It was the most frequent location of the rash (46%), followed by the arms (40%), the face (38%) and the legs (37%). More than a third of cases with available data reported rash in four or more regions.
However, early warning signs of illness are less common in the current outbreak compared to “typical” monkeypox. In about 2 out of 5 cases, the illness began with the rash, but no prodromal symptoms such as chills, headache, or malaise were reported. About 2 out of 5 cases also reported no fever.
The report’s authors emphasize that anyone with a rash consistent with monkeypox should be tested for the virus, regardless of sexual or gender identity or the presence of other symptoms.
Among the cases for which data were available, fewer than 1 in 10 (8%) required hospitalization for monkeypox. No deaths were reported.
Of those whose vaccination status was available, 14% had been vaccinated against smallpox, including 3% who had received a dose of Jynneos during this outbreak. At least one person with monkeypox had symptoms more than three weeks after receiving the first dose of the Jynneos vaccine.
A “substantial proportion” of monkeypox cases have been reported among people with HIV, who may be at increased risk of severe disease. Further testing of this group is underway, according to the CDC.
The agency says it is “continually evaluating new evidence and adapting response strategies as information on changing case demographics, clinical characteristics, transmission, and vaccine effectiveness becomes available.”