HONG KONG, April 7 (Xinhua) -- About 502,500 Hong Kong residents have taken the first jab of the COVID-19 vaccine, official data showed. The Hong Kong Special Administrative Region government has said some 113,000 people have been fully vaccinated under the mass inoculation program starting on Feb. 26. Hong Kong's Center for Health Protection reported eight new confirmed cases on Wednesday, including two untraceable local infections. There were also 10 preliminary positive cases, mostly imported. The COVID-19 tally stood at 11,539 in Hong Kong.