A Chinese Covid-19 vaccine candidate based on inactivated coronavirus is safe and elicits an antibody response, preliminary results have shown.
The research, published in the journal Lancet Infectious Disease, is based on small early phase randomised clinical trials involving 640 participants.
Scientists said those aged 60 and over were slower to respond, with antibodies taking up to 42 days to be detected in blood tests, compared with 28 days for participants aged 18 to 59.
They also found antibody levels to be lower in those aged 60 to 80 years, compared with those aged 18 to 59.
The researchers said the trial was not designed to assess efficacy of the vaccine, however, so it is not possible to say whether the antibody responses induced by the vaccine, called BBIBP-CorV, are sufficient to protect from coronavirus infection.