Beijing, Dec 19 : China will start inoculating some key groups with Covid-19 vaccines in this winter-spring period before expanding the vaccination drive to a wider population, said a National Health Commission (NHC) official in Beijing on Saturday. China's Covid-19 vaccine development has entered the "final sprint", with five vaccines undergoing phase-3 clinical trials, Xinhua news agency reported. In a two-step vaccination drive, the vaccines will be first given to priority groups, including those engaged in handling imported cold-chain products, and people working in sectors such as port inspection and quarantine, aviation, public transport, fresh market, medical treatment and disease control, Cui Gang, an official with NHC's disease control department, said at a press conference. The vaccination programme will also cover those who plan to work or study in countries and regions with medium or high risks of exposure to the virus, Cui added. This will help relieve the pressure on China in preventing and controlling imported Covid-19 cases, and lower the risks of domestic outbreaks of the epidemic, said Cui. Next, with Covid-19 vaccines officially approved to enter the market or the yield of vaccines improving steadily, China will put more vaccines into use, inoculating the eligible population as widely as possible, Cui said. "This will gradually forge a barrier of immunity among the public to stop the spread of Covid-19 in China," Cui said. The State Council joint prevention and control mechanism against Covid-19 has ordered the strict inspection of vaccine quality, safe and smooth cold-chain transportation, as well as timely and accurate delivery of vaccines, said Zeng Yixin, deputy head of the NHC. The mechanism has also emphasised the importance of providing medical support and service, especially timely treatment and reporting of adverse reactions, during the vaccination drive, Zeng said. /IANS