A coronavirus vaccine tested for the first time in humans is safe and induces a rapid immune response, researchers at China's CanSino Biologics Inc reported on Friday in The Lancet medical journal.
Blood samples from a group of 108 vaccinated adults showed both neutralising antibodies and T-cell responses against the novel coronavirus in most of those tested, reports Reuters.
Further studies will be needed to confirm whether the vaccine protects against infection.
"These results represent an important milestone. The trial demonstrates that a single dose of the new adenovirus type 5 vectored COVID-19 (Ad5-nCoV) vaccine produces virus-specific antibodies and T cells in 14 days, making it a potential candidate for further investigation," co-author Professor Wei Chen from the Beijing Institute of Biotechnology in Beijing said in a statement.
"However ... the ability to trigger these immune responses does not necessarily indicate that the vaccine will protect humans from COVID-19 ... we are still a long way from this vaccine being available to all."
More than 100 vaccine candidates against SARS-CoV-2 are in development, with about 12 in human testing designed to mainly evaluate safety. A few, including CanSino's, have moved to larger mid-stage studies that are evaluating safety and the ability to induce an immune response.
Healthy adult volunteers in Wuhan, China, received a single intramuscular injection of either a low, middle or high dose of the vaccine.
Four weeks after the injection, the most common adverse reactions were mild pain at the injection site, fever, fatigue, headache, and muscle pain. There were no serious adverse events.
A mid-stage trial of the vaccine is already underway in Wuhan.