People leave a makeshift nucleic acid testing site during the second round of mass testing for the coronavirus disease (COVID-19) at Fengtai district in Beijing, China January 25, 2022. REUTERS/ Florence Lo

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BEIJING, Jan 27 (Reuters) – China’s Walvax Biotechnology (300142.SZ) has recruited most of the 28,000 participants needed for a large clinical trial of its COVID-19 mRNA vaccine candidate, a senior company official said on Thursday.

China has not yet approved a Chinese new messenger RNA (mRNA) technology vaccine and has not yet imported a foreign mRNA vaccine.

The problem has become more pressing as studies have shown that the most commonly used Sinovac and Sinopharm injections in China are less effective against the highly contagious Omicron than against some previous variants.

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Beginning next week, a Phase III trial for Walvax’s potential mRNA vaccine will shift from recruiting participants to identifying potential COVID-19 infections for data analysis, the vice president said Thursday. by Walvax, Huang Zhen.

He declined to provide a timeline for when the trial might establish the vaccine’s effectiveness.

“The first step is to identify all of these cases and not miss any,” Huang said in a phone call, fearing that some participants might report their illness for fear of being quarantined.

Recruitment of foreign participants for the trial was slow at first, but accelerated after researchers shifted recruitment to smaller, less vaccinated cities.

The ARCoV vaccine, which Walvax co-developed with Suzhou Abogen Biosciences and a Chinese military-backed research institution, is currently being tested in a phase III trial in countries including China, Mexico and Indonesia.

Finding and analyzing cases from a phase III trial is essential for calculating the effectiveness of a vaccine, which usually requires comparing the number of cases among vaccinated and unvaccinated people.

Another China-based clinical trial to test ARCoV as a booster dose has recruited more than 1,000 participants and collected blood samples for analysis, Huang said, without saying when the results might be ready.

Walvax has an annual capacity to manufacture 200 million doses of the vaccine in bulk form, and the company intends to increase that capacity, Huang said.

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Reporting by Roxanne Liu and Ryan Woo; edited by Barbara Lewis

Our standards: The Thomson Reuters Trust Principles.