Public health officials successfully contained a potential mpox outbreak in New Hampshire, averting additional cases. The swift response involved a person diagnosed with mpox who had contact with individuals at two congregate living facilities, a healthcare setting, and their home.
A report highlights that prompt testing and the administration of postexposure prophylaxis (PEP) using the Jynneos vaccine to 90% of those at risk, primarily within six days of exposure, likely prevented further spread. The report was compiled by the New Hampshire Department of Health and Human Services (NHDHHS), the US Centers for Disease Control and Prevention (CDC), and Dartmouth-Hitchcock Medical Center.
In February 2025, health authorities were alerted to a resident exhibiting symptoms of fever, nausea, vomiting, and genital lesions after returning from a trip to East Africa. The individual sought care at a local hospital emergency department upon their return. Initially discharged without mpox testing, the patient returned four days later with more widespread lesions on their face, mouth, throat, and hands, leading to airborne isolation and a positive mpox virus (MPXV) test. The PCR testing confirmed the presence of clade 1b, a rare mpox strain in the United States.
Investigations revealed potential exposures at two adult disability group homes where the patient worked, leading to close contact with five staff members and twelve residents. Two healthcare workers were also exposed during the patient’s initial emergency department visit when they examined the lesions without appropriate personal protective equipment.
A total of 20 individuals, including group home contacts, healthcare workers, and a household member, were recommended for Jynneos vaccination. While two intermediate-risk co-workers were later reclassified as lower risk, 18 of the 20 contacts received PEP. The vaccine was administered within eight days of initial exposure, with a median of six days.
Although the ideal window for PEP effectiveness is considered to be within four days of exposure, this benchmark was not met for any of the contacts. However, the rapid rollout of PEP is credited with preventing further transmission of the clade 1 MPXV strain. The authors emphasize the continued need for rapid public health responses to travel-associated mpox cases, given ongoing outbreaks in Africa.
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