Possible Undetected Mpox Infection Among Persons Accessing Homeless Services and Staying in Encampments — San Francisco, California, October–November 2022

Self Cite

Since May 2022, mpox has been identified in 108 countries without endemic disease; most cases have been in gay, bisexual, or other men who have sex with men. To determine number of missed cases, we conducted 2 studies during June–September 2022: a prospective serologic survey detecting orthopoxvirus antibodies among men who have sex with men in San Francisco, California, and a retrospective monkeypox virus PCR testing of swab specimens submitted for other infectious disease testing among all patients across the United States. The serosurvey of 225 participants (median age 34 years) detected 18 (8.0%) who were orthopoxvirus IgG positive and 3 (1.3%) who were also orthopoxvirus IgM positive. The retrospective PCR study of 1,196 patients (median age 30 years; 54.8% male) detected 67 (5.6%) specimens positive for monkeypox virus. There are likely few undiagnosed cases of mpox in regions where sexual healthcare is accessible and patient and clinician awareness about mpox is increased.

Section: Discussionsupporting

confidence: 68%

Prevalence of Undiagnosed Monkeypox Virus Infections during Global Mpox Outbreak, United States, June–September 2022

Minhaj,

Singh,

Cohen

et al. 2023

Self Cite

“…In a historically marginalized population that experiences multiple barriers to healthcare, it is probable that not all PEH with mpox symptoms received the necessary medical attention for diagnosis and treatment. A serosurvey conducted by CDC among 209 persons experiencing homelessness found 3 possible missed cases of mpox ( 23 ), suggesting a small, but present, negative case detection bias from mpox surveillance based on case reporting. This bias may also have affected LACDPH’s assessment of transmission within shelters and encampments, particularly because contact tracing is more challenging among PEH than among the general population.…”

Section: Discussionmentioning

confidence: 99%

Epidemiologic Characteristics of Mpox Infections among People Experiencing Homelessness, Los Angeles County, California, USA, 2022

Brosnan¹,

Yeh²,

Jones³

et al. 2023

In Los Angeles County, California, USA, public health surveillance identified 118 mpox cases among persons experiencing homelessness (PEH) during July–September 2022. Age and sex were similar for mpox case-patients among PEH and in the general population. Seventy-one (60%) PEH mpox case-patients were living with HIV, 35 (49%) of them virally suppressed. Hospitalization was required for 21% of case-patients because of severe disease. Sexual contact was likely the primary mode of transmission; 84% of patients reported sexual contact < 3 weeks before symptom onset. PEH case-patients lived in shelters, encampments, cars, or on the street, or stayed briefly with friends or family (couch surfed). Some case-patients stayed at multiple locations during the 3-week incubation period. Public health follow-up and contact tracing detected no secondary mpox cases among PEH in congregate shelters or encampments. Equitable efforts should continue to identify, treat, and prevent mpox among PEH, who often experience severe disease.

“…Second, the infectivity and duration of viral shedding were not evaluated in asymptomatic cases, thereby limiting our understanding of the role of asymptomatic persons in MPXV transmission. Finally, the study did not use MPXV antibody testing because of the low specificity of currently available modalities ( 12 , 13 ); thus, we might have missed additional asymptomatic mpox cases.…”

Section: Discussionmentioning

confidence: 99%

Prevalence of Asymptomatic Mpox among Men Who Have Sex with Men, Japan, January–March 2023

Mizushima¹,

Shintani²,

Takano³

et al. 2023