BEIJING -- China encourages voluntary COVID-19 vaccinations, and works to ensure all people eligible for vaccination have access to it, an official with Chinese health authority said on Sunday.

People aged above 18, as active participants in social activities, are the majority of vaccine receivers, said Wu Liangyou, an official with the National Health Commission (NHC), at a press conference.

Vaccinations not only protect themselves, but also their family members, especially children and the elderly, Wu added.

China has accelerated COVID-19 vaccine rollouts among priority populations, as well as in key regions and cities, said NHC spokesperson Mi Feng at the same press conference, demanding rectification of compulsory COVID-19 vaccination in some places in the country.

Meanwhile, Wu Zunyou, chief epidemiologist with the Chinese Center for Disease Control and Prevention, warned against relaxing self-imposed prevention in spring, especially during the upcoming May Day holiday.

Wu Zunyou urged people to strictly follow prevention measures, including wearing masks in public, handwashing, social distancing, and avoiding mass gatherings.

China still faces risks of an epidemic rebound due to imported cases, said Wu Zunyou. He cited the example of Ruili city in southwest China's Yunnan Province, where new cluster infections were reported in late March.