For the first time in decades, China reported a human outbreak of vaccinia virus (VACV), according to a study yesterday in Emerging Infectious Diseases.

VACV is an orthopoxvirusvirus that is used in the live-virus vaccine against smallpox. It is related to cowpox and monkeypox viruses and can cause severe illness in humans.

Exposure from inoculated lab rabbits

The study details how five Chinese powder processing workers contracted VACV in 2017, after pulverizing a batch of frozen rabbit skins. The animals had been inoculated with VACV in a pharmaceutical lab 5 days previously, and their pulverized skin was being studied for analgesic properties.

All five case-patients handled the pulverized skin in an enclosed workspace over the course of 1 hour, and none wore personal protective equipment. Three other employees who were also in the workplace—but wore masks and did not handle the pulverized skin directly—did not contract the virus.

All five case-patients developed pulmonary infections marked by high fevers within 5 days of the exposure, and three of them went on to develop vesicular-pustular lesions on their hands, the authors said. One patients was hospitalized, and the others were treated at home with anti-inflammatory medications and instructed to avoid close contact with friends or family members until they were without fever and their lesions had healed.

Molecular data collected from patient samples tested positive for VACV.

iStock, unoL

Three of the patients had received prior smallpox vaccination and had less severe clinical manifestations than the others, the authors said. This indicated that vaccination may have reduced illness severity.

Read more at CIDRAP…

See also:

Apr 23 Emerg Infect Dis study