On Wednesday the Hung Yen Province People's Court in northern Vietnam found Hoang Thi Hien, 50, guilty of violating medical regulations and prohibited her from practicing for three years after her release.

She also has to pay compensation of more than VND2.2 billion ($94,850) to 111 out of the 117 victims. The parents of the remaining six children could not prove that her service was the only source of their infection.

The court said Hien ran an unlicensed medical facility at home for genital examination of children, charging up to VND520,000 ($22) for treating phimosis, a congenital narrowing of the foreskin of the penis so that it does not retract.

An investigation found she had used unsterilized equipment to treat phimosis by widening the foreskin. This had caused the children to contract human papillomavirus, or HPV, the direct cause of their warts.

The outbreak occurred in July 2017 with around 80 boys, most of them under two, being diagnosed with the HPV infection, causing health inspectors to begin an investigation.

Genital warts are caused by certain strains of HPV, which can lead to vulval, penile and anal cancers, though it is usually sexually transmitted.