With just 288 infections and no deaths, the Southeast Asian nation has seen no community infections for nearly a month, putting it on course to resume activities sooner than most others in the region.

"The teachers told us to use hand sanitizer and not to touch one another at school," a fifth grade student, Vu Tuan Phong, said outside his primary school in Hanoi.

He and his schoolmates went home at mid-day, as most schools are following a shorter day than before the pandemic.

"Parents, myself included, trust that the government, as well as the school, will take the optimal measures so kids are safe being in school and parents have peace of mind going to work," said one mother in the capital, Ngoc Anh, 29.

The school re-opening is Vietnam's latest step in lifting virus curbs, although international commercial flights and dance clubs and karaoke bars remain banned.

Schools for older children reopened partially last week.

"The risk of COVID-19 [in Vietnam] is low now, and that's a good thing," Prime Minister Nguyen Xuan Phuc said last week. "But we need to stay vigilant."