Findings from phase three studies will be crucial for determining if the immune response generated by CoronaVac is sufficient to protect from infection.
According to the paper, antibody responses could be induced within 28 days of the first immunisation, by giving two doses of the vaccine candidate 14 days apart.
The study only included healthy adults aged 18 to 59 years and further studies will be needed to test the vaccine candidate in other age groups, as well as in people who have pre-existing medical conditions.
Professor Fengcai Zhu, joint lead author of the study, from the Jiangsu Provincial Centre for Disease Control and Prevention, Nanjing, China, said: “Our findings show that CoronaVac is capable of inducing a quick antibody response within four weeks of immunisation by giving two doses of the vaccine at a 14-day interval.
“We believe that this makes the vaccine suitable for emergency use during the pandemic.
“In the longer term, when the risk of Covid-19 is lower, our findings suggest that giving two doses with a one-month interval, rather than a two-week interval, might be more appropriate for inducing stronger and potentially longer-lasting immune responses.
“However, further studies are needed to check how long the antibody response remains after either vaccination schedule.”