Picture shows inactivated vaccines produced by Sinopharm's Wuhan institute Photo: Changjiang Daily Sina Weibo account

Chinese vaccine manufacturer Sinopharm said on Wednesday that they had released the world's first report of Phase III clinical trials on inactivated COVID-19 vaccines. The report shows that two inactivated vaccines, developed by the group's Wuhan and Beijing institutes, demonstrated an efficacy of 72.8 percent and 78.1 percent respectively. 

The report was published by The Journal of the American Medical Association on Wednesday, and shows the results of the preliminary analysis of Phase III clinical trials on the vaccines that kicked off on July 16, 2020. 

Data collected for the analysis on efficacy and adverse events were locked on December 20 and 31, 2020, respectively.

The trials are still undergoing and the evaluation on long-term efficacy and protection continues, the company said. 

The 40,382 participants randomized to receive at least one dose of the two-doses vaccines or an aluminium hydroxide-only control, according to the report released Wednesday.

During a follow-up average period of 77 days, 26 symptomatic cases of COVID-19 were identified in the group of the Wuhan institute vaccine and 21 in the Beijing institute vaccine group, resulting in an efficacy of 72.8 percent for Wuhan group and 78.1 percent for the Beijing group, read the report. 

Severe cases of COVID-19 were not registered in the two vaccine groups. Light adverse reactions seven days after each injection occurred in 41.7 percent to 46.5 percent of participants in the three groups, including sore arm and headache. 

The report concluded that "in this prespecified interim analysis of a random clinical trial, treatment of adults with either of 2 inactivated SARS-CoV-2 vaccines significantly reduced the risk of symptomatic COVID-19 and serious adverse events were rare."  

The vaccines developed by Sinopharm's Beijing institute has been approved by the World Health Organization (WHO) for emergency use. The group's two vaccines have been approved for emergency use by more than 70 countries, regions and organizations.

Sinovac, another Chinese producer whose inactivated COVID-19 is under WHO's review for emergency use. Data released by Sinovac's Brazilian partner showed that its vaccine has an efficacy of 50.7 percent and has proved to be effective against the P1 and P2 variants that are prevalent in Brazil.