Sinovac Biotech's experimental Covid-19 vaccine triggered a quick immune response, but the level of antibodies produced was lower than in people who had recovered from the disease, preliminary trial results showed yesterday.
It's not clear if the shot protects people from getting sick with COVID-19 - but the trial does show, it generates an immune response that would be expected to provide protection.
LondonOxford University's corona virus vaccine has caused immune response in healthy people aged 56-69 years and over 70 years.
In this phase, the scientists said 600 healthy volunteers were enrolled in the study, who were separated into two groups for the 14-day and 28-day vaccination schedule, and then randomly assigned to receive either a low dose of the vaccine, a high dose, or placebo.
Investigator at the Oxford Vaccine Group and consultant physician Dr Maheshi Rasamy said the fact that older people had a better response to the vaccine was a positive step forward.
Adverse effects were less common in older adults than in younger adults and similar levels of local symptoms were seen after the first and booster doses of the Oxford COVID-19 vaccine in older adults, while there were few systemic symptoms following the booster dose.
A Chinese COVID-19 vaccine seems to be safe and effective, early trial results suggest, but one expert says the findings should be regarded with caution.
Further phase 3 studies will be "crucial" to determine the full efficacy of the vaccine against SARS-CoV-2, the study said, adding that additional tests with other age groups and patients with pre-existing conditions would also need to be trialled.
They noted that the trial's primary objective was to evaluate the vaccine's immune response and safety. "We are confident that in the next weeks or month we will have the vaccine not only in use in the USA and Europe, but also in Latin American countries".
Almost a million people have taken an experimental coronavirus vaccine developed by Chinese company Sinopharm, the firm said, although it has not yet provided any clear clinical evidence of efficacy.
The UK has already ordered 100 million doses of the Oxford vaccine, being manufactured by pharma major AstraZeneca. Oxford is developing its vaccine in conjunction with the drugmaker AstraZeneca. This is the last stage before seeking regulatory approval, and includes tracking the effectiveness of the vaccine in preventing coronavirus.