China's first single-shot vaccine, and the country's third COVID-19 vaccine overall, recorded an efficacy of 74.8 percent in phase-3 trials in Pakistan, a Pakistani official said on Monday.

The vaccine, developed by CanSino Biologics Inc. (CanSinoBIO) and a team led by Chen Wei, a researcher from the Beijing-based Academy of Military Medical Sciences, showed 74.8 percent efficacy in preventing symptomatic cases and a 100-percent success rate in preventing severe disease among Pakistanis, according to Special Assistant to the Prime Minister on Health Dr. Faisal Sultan. 

He also said an interim analysis conducted in multiple countries including Pakistan showed 65.7 percent efficacy at preventing symptomatic cases and 90.98 percent at preventing severe disease, according to the Independent Data Monitoring Committee.

The vaccine, Ad5-nCoV, is the first COVID-19 vaccine in the world that has entered the second phase of clinical trials, according to the World Health Organization. It is also one of the only two one-dose vaccines in the world to release its phase-3 data. The other one-dose vaccine was developed by Johnson & Johnson. The single-shot vaccine can be more effective to execute mass vaccination. 

No severe adverse cases related to the vaccine have occurred in trials across the world. Sultan said the data comes from an analysis of 30,000 participants, with only 101 confirmed COVID-19 cases. 

CanSinoBIO in a statement on February 1 said that over 40,000 people had been vaccinated in the phase-3 trial in five countries - Mexico, Russia, Pakistan, Argentina and Chile.