Shanghai health officials on April 4 defended separating babies and young children from their parents if they test positive for Covid-19, as frustration at the city’s tough virus controls builds.

Around 25 million people remain locked down in China’s largest city and financial centre, as authorities try to snuff out what is likely the country’s most severe virus outbreak since the end of the first pandemic wave in early 2020.

Under China’s unbending virus controls, anyone found positive – even if they are asymptomatic or have a mild infection – must be isolated from non-infected people.

That includes children who test positive but whose family members do not, health officials confirmed on April 4, defending a policy which has spread anxiety and outrage across the city.

“If the child is younger than seven years old, those children will receive treatment in a public health centre,” said Wu Qianyu, an official from the Shanghai Municipal Health Commission.

“For older children or teenagers … we are mainly isolating them in centralised [quarantine] places.”

Frustration is mounting in Shanghai, which on April 4 recorded 9,000 new virus cases, with parents and guardians voicing their anger at the policy on social media.

“Parents need to meet ‘conditions’ to accompany their children? That’s absurd … it should be their most basic right,” one unnamed commenter wrote on social media platform Weibo.

Unverified videos of babies and young children in state-run wards have been widely shared.

But Shanghai official Wu said the policy was integral to virus “prevention and control work”. She added that children and parents who test positive would be able to stay together as a family.