CanSino Biologics Inc's single-dose Covid-19 vaccine, given at a lower dosage than that for adults, is safe and triggers an immune response in children aged 6-17, results from a small trial showed, Reuters reports.

Researchers decided to lower the dosage after a few participants developed fever and headaches graded at level 2 severity — the second-lowest of four levels.

In children, the lower dose triggered higher antibody levels than the dosage approved for use in adults in China, according to the peer reviewed finding supplementary data from a mid-stage trial. The trial recruited 150 children and around 300 adults.