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BEIJING, Jan. 18 (Reuters): China’s Sinovac Biotech said on Monday that a clinical trial in Brazil showed its Covid-19 vaccine to be nearly 20 percentage points more effective in a small subset of patients who received their two doses further apart. .
The protection rate for 1,394 participants who received doses of CoronaVac or placebo three weeks apart was nearly 70%, a Sinovac spokesperson said.
Brazilian researchers announced last week that the overall efficacy of the vaccine was 50.4% based on results from more than 9,000 volunteers, most of whom received doses 14 days apart, as outlined in the trial protocol.
The spokesperson said that a small number of participants were shot late for a second time due to various reasons, without elaborating.
The dosage range for Covid-19 vaccines has become a hot topic of debate among scientists, regulators, and governments.
UK regulators have said that a Covid-19 vaccine from AstraZeneca and the University of Oxford is more effective when there is a longer gap between doses than initially intended.
Britain has also decided to allow a longer gap between the doses of a Covid-19 vaccine from Pfizer and BioNTech, although the companies say they only have efficacy data for a shorter period between injections.
The Sinovac spokesperson cautioned that the robustness of the subgroup data was weaker than the 50% result, which is based on pooled data from those who received doses two to three weeks apart.
While Sinovac researchers had said that early-stage trials showed that an interval of four weeks induced a stronger antibody response than two weeks, this is the first time the company has published efficacy data from a phase trial. III with dosing patterns that differ from your assay protocol.
Sinovac has yet to release the global results of its phase III trials, but its Covid-19 vaccine has been approved for emergency use in several countries, including Brazil, Indonesia and Turkey. – Reuters
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