Photo: A screenshot from the Clover Biopharmaceuticals website

Chinese people are about to embrace a new COVID-19 vaccine, which experts predicted could be the most effective developed in China, as the latest research showed 79 percent efficacy against the dominant Delta variant and overall 67 percent efficacy against any variants. 

The vaccine, a protein-based COVID-19 vaccine candidate developed by Chengdu-based Clover Biopharmaceuticals, is also the world's first COVID-19 vaccine that has been proven effective against all three mutations (Delta, Gamma and Mu), Zhuang Shilihe, a Guangzhou-based vaccine expert, told the Global Times on Thursday.

Clover announced on its website on Wednesday that it had achieved the primary efficacy endpoint and secondary efficacy endpoints in SPECTRA, a global pivotal phase II-III clinical trial. 

The results showed that the candidate, SCB-2019, demonstrated 79 percent overall efficacy against COVID-19 of any severity caused by the globally dominant Delta variant, which currently comprises more than 90 percent of all cases worldwide.

Efficacy was 92 percent against the Gamma variant and 59 percent against the Mu variant, and collectively these three strains (Delta, Gamma and Mu) comprised 73 percent of all strains identified in the study, according to an announcement the company released on its website on Wednesday.  

Overall efficacy was 67 percent against COVID-19 of any severity caused by any strain in the study, successfully meeting the primary endpoint of the trial. Clover's vaccine candidate is one of the first to demonstrate significant efficacy against Delta in a double-blind, randomized clinical trial, read the announcement.  

The overall efficacy is not bad, given the severity of the variants used in the clinical trial, Zhuang said. "We can say that the Clover candidate faces the most severe phase III environment than any previous one did, such as Pfizer, Oxford and Sinovac candidates," he noted.  

The SPECTRA clinical trial enrolled over 30,000 adult and elderly (18 years of age or older) participants at 31 sites in five countries (Philippines, Brazil, Colombia, South Africa, Belgium) across four continents, resulting in one of the most diverse COVID-19 vaccine clinical trials conducted to date, Clover said. 

Accrual of COVID-19 disease cases for the final efficacy analysis occurred from April 28 through August 10, 2021 - a time when the Delta variant of SARS-CoV-2 became the dominant strain globally, Clover noted in the announcement.

The vaccine also shows 100 percent efficacy against severe COVID-19 and hospitalization, and 84 percent efficacy against moderate-to-severe COVID-19, caused by any strain of SARS-CoV-2 in the SPECTRA clinical trial, according to the company.

It is also the first COVID-19 vaccine to demonstrate significantly reduced risk of COVID-19 disease in previously infected individuals as vaccination with SCB-2019 reduced the risk of symptomatic COVID-19 reinfection caused by any strain by 64.2 percent in previously infected participants. 

The risk of symptomatic COVID-19 reinfection caused by Delta was reduced by 79.1 percent, the company noted. 

Clover plans to make submissions for conditional approval applications to global regulatory authorities (including China's National Medical Products Administration, European Medicines Agency and the World Health Organization) in the fourth quarter of 2021. Upon receiving conditional approval, Clover plans to commence the initial product launch of the vaccine potentially by the end of 2021, according to the company website.