China will keep implementing its dynamic zero COVID-19 strategy to contain the outbreaks in Jilin province and Shanghai, where case numbers are still high, senior officials said at a news conference on Wednesday.

National Health Commission spokesman Mi Feng said the nation faces a grim challenge in preventing and controlling the epidemic as it continues to promote vaccinations, especially among the elderly.

"As of April 5, around 3.28 billion doses of vaccines have been administered, and over 1.24 billion people have been fully vaccinated," he said.

"Shanghai is now at a critical point in its fight against the epidemic. The commission has so far coordinated over 38,000 medical workers from 15 provinces to aid the city. These workers can perform 2.38 million nucleic acid tests per day."

Lei Zhenglong, deputy head of the NHC's disease prevention and control bureau, said at the conference that five provinces — including Guangdong, Shandong and Hebei, all of which have been hit by sporadic outbreaks — are gradually recovering thanks to strict control measures that have been in place since mid March.

However, the situation remains critical in Jilin and Shanghai.

He said that Shanghai has so far reported over 90,000 confirmed and asymptomatic cases, while Jilin has reported 60,000.

"The previous examples showed that taking strict measures to test and quarantine the infected is necessary and scientific to contain the expansion of the epidemic caused by the Omicron variant in order to reach the dynamic zero target," Lei said. "We will help improve local authorities' ability to deal with the epidemic using strict and prompt measures."

Wu Zunyou, chief epidemiologist at the Chinese Center for Disease Control and Prevention, added at the conference that as long as we insist on the dynamic zero COVID-19 strategy, the situation will get better soon.

"As neighboring countries and regions, including the Hong Kong Special Administrative region, face severe challenges in their fight against COVID-19, we are also facing great pressure to prevent imported cases," he said.

"So it's necessary to report immediately whenever confirming an infection and taking quarantine and treatment in a timely manner," he said. "The public should understand and give their support to the epidemic control measures, and they are encouraged to cultivate good health habits such as wearing masks and maintaining social distance."