Baotou city -- located in North China's Inner Mongolia autonomous region -- has started the emergency use of COVID-19 vaccine candidates on certain key groups of people, according to the Baotou Center for Disease Control and Prevention.

Local officials said that strictly guided by the relevant requirements and arrangements of the country and the autonomous region, vaccinations are being implemented in two stages.

In the first stage, they will mainly be given to key groups of people who have a relatively high risk of infection.

Officials said these include those working in import cold chain facilities, port inspections and quarantines, ship pilots, aviation air services, fresh food markets, public transportation and medical disease control staff members.

In the second step, as the vaccine production gradually increases, more vaccines will be given.

Officials said that through their orderly distribution, an immune barrier for residents will be gradually be built up -- the so-called herd immunity effect -- to block the spread of the COVID-19 in the country.

The vaccination work for key groups of people began on Dec 25 and will be completed on Feb 5, 2021.

Those receiving the vaccine need to take two shots at an interval of 28 days.