Clover Biopharmaceuticals (Clover) , a clinical stage biotechnology company in China, has said that according to researchers, an experimental COVID-19 vaccine developed by the company appeared to be safe and able to trigger immune responses in animal tests, Reuters news agency reported on Friday.

The result of this study on monkeys comes months after Clover began an early stage human trial in Australia in June 2020.

Clover's vaccine candidate, called S-Trimmer, which is partly funded by a global vaccine research coalition, uses adjuvants, ingredients that could boost immune responses, from Britain's GlaxoSmithKline and US-based Dynavax Technologies.

Researchers at Clover and other Chinese institutes said in a paper published on 24 September 2020, ahead of peer-review, that two doses of the candidate with GSK's adjuvant induced antibody levels in monkeys that are higher than those seen in the blood of patients recovering from COVID-19.

Also, antibody levels triggered by two doses of the vaccine with Dynavax's adjuvant, plus alum, were similar to those observed in convalescent patients' serum, they said. Reportedly, adjuvants could reduce the amount of antigen, the substance that triggers immune responses, required in each vaccine dose, allowing manufacturers to make more doses.

In addition, the candidate did not cause a disease enhancement effect when tested in monkeys, which experts worry may happen to coronavirus vaccines.