Monkeypox virus isolation from longitudinal samples from four patients to infer risk of onwards transmission: an interim analysis.

Monkeypox virus (mpxv) is a DNA virus in the Orthopoxvirus genus which causes Mpox (previously monkeypox). Symptoms include fever, lymphadenopathy and vesicular lesions. There is limited evidence for the duration of mpxv infectivity. This study used cell culture as a proxy for infectivity. Clinical samples from four patients with Mpox were inoculated into African green monkey kidney (Vero E6) cells and monitored for cytopathic effects (CPE). From one patient, infectious mpxv was recovered 25 days after illness onset. Infectious virus was not isolated from samples with an Orthopoxvirus polymerase chain reaction (PCR) Ct value over 31.0, nor from urine.