About 180,000 people in key groups in Guangdong, China's most populous province, had received free COVID-19 vaccine shots by Tuesday, with no serious side effects reported.

The groups include workers involved in cold chain import logistics, quarantine venues, customs and immigration inspection, cross-border transport, healthcare, front-line epidemic control and public transport, and those working or studying overseas.

They are considered high-risk groups and more prone to infection. Their vaccination is meant to protect their health and help control the pandemic, Duan Yufei, director of the provincial health commission, told a news conference in Guangzhou on Wednesday.

All people in the key groups who are physically suitable for COVID-19 vaccination should receive the inoculation, Duan said.

Vaccinations will be expanded to the general public after the vaccines are officially launched and supply increases, he said.

Even after the vaccines enter the market, the public should still exercise full epidemic control measures for a considerable period of time, he said.

Guangdong remains a low-risk region and current measures have proved effective in controlling the epidemic, Duan said, adding that the province can conduct 1.45 million nucleic acid tests a day.

After the central authorities started vaccination work, the Guangdong provincial authorities allocated funds, procured vaccines, distributed the vaccines to localities, regulated vaccine storage and warehousing, established expert terms to formulate plans and trained inoculation personnel.

Every vaccinated person is recorded and each dose of vaccine is traceable, he said, with medical support in place at inoculation venues.

Deng Huihong, director of the provincial center for disease control and prevention, said, however, that some people are not suitable for vaccination at the moment. They include those younger than 18 and older than 59, those who have experienced serious side effects after receiving other vaccines, pregnant women, and those with acute diseases, serious chronic diseases or fever.

People who have received the COVID-19 vaccine shots are required to download a mobile phone app to report their health conditions every day for a week.

Appointments for vaccinations are made by organizations representing the key groups. The city authorities in Guangdong will issue information later on inoculation sites for those planning to work or study overseas, Deng said.

Meanwhile, an investigation has revealed that a 31-year-old woman worker at a quarantine hotel in Guangzhou's Nansha district who was confirmed as an asymptomatic carrier on Sunday was infected by a visitor from Myanmar who stayed at the hotel, Duan said.

Strict testing and screening among related people and management of related places was implemented after the case was reported, and the risk of further transmission is low, he said, adding that the management of quarantine hotels across the province has been strengthened.

As the end of the year approaches, Deng encouraged organizations to hold online annual meetings. If offline meetings are necessary, invitations should not be extended to people from other provinces. Pandemic control contingency plans must be in place for meetings with over 50 participants, she said.