He Fangmei, the mother of a baby made sick by a faulty vaccine, was initially detained by police from her home province of Henan on Feb. 25 during a protest by parents of children affected by tainted and out-of-date vaccines outside the National Health Commission in Beijing, rights groups said.
He, who is also known by her online nickname Shisanmei, was initially handed a 15-day administrative sentence after being sent back to her home city of Xinxiang on March 5 under escort.
However, her husband Li Xin told RFA that she has now been formally arrested, and is being held in the Xinxiang Detention Center on charges of "picking quarrels and stirring up trouble."
"Village officials told me on Monday that she had been formally arrested, on the same charge of picking quarrels and stirring up trouble," Li said.
"They didn't give me a notification of formal arrest, which would have been easy for them to do ... I think it's just another way for them to delay things," Li said. "They're afraid I would post it online."
Li said police are likely delaying He's case in a bid to put pressure on her to "confess" to the charges against her.
"They are trying to force her to confess, after which she will sign their so-called agreement, which would probably result in her release," he said. "But Shishanmei refuses to confess. She won't back down."
Li said he didn't think his wife had done anything wrong.
"What we were asking for was normal; I wouldn't be kicking up a fuss if there was nothing wrong," he said. "But the authorities just see it as trouble-making, and they bring in stability maintenance."
But he said he had been warned off any further protests or petitioning activities.
"The higher-ups said that I wasn't to persist in illegal petitioning. No more shouting slogans outside the health ministry," he said, adding that the authorities had asked him to sign a guarantee that they would stop campaigning, in order to get his wife out of jail.
Li said he had signed it in the hoping of see He released, but that she had been formally arrested instead.
Prison sentence likely
He's defense attorney Gao Chengcai said he had recently visited his client in the detention center, where she seemed in good spirits.
But he said her case would now likely result in a prison sentence.
"She will definitely be found guilty of picking quarrels and stirring up trouble," Gao said. "There is no difference between legal or illegal, reasonable or unreasonable nowadays."
"Once she has been formally arrested, that's what she will be sentenced for in 99 percent of cases," he said.
A fellow vaccine parent surnamed Xu said that local governments in many areas of China have begun turning their attention to the needs of victims in recent days, and offering them support and assistance.
"The government seems to think that we're extremists, to a certain extent," Xu said. "Maybe it led to breaking the law; a small number of parents have been detained, but ... the government is doing something to help these families now."
A duty officer who answered the phone at the state prosecutor's office in Huixian city, which falls under the administration of Xinxiang, declined to comment when contacted by RFA on Wednesday, saying it was a public holiday.
Parents protest in Beijing
Around 30 parents of children made sick by substandard and expired vaccines gathered outside the National Health Commission headquarters on Feb. 22, ahead of the annual parliamentary sessions in Beijing, calling on the government to deliver on earlier promises of assistance.
He Fangmei told RFA at the time that the parents-turned-activists were hoping to use heightened media attention around the National People's Congress (NPC) meeting in early March to publicize their families' grievances.
"We want the government to finish work on a Vaccine Law, taking into account suggestions from parents like us," she said. "That includes early intervention and treatment and guarantees in the longer term."
"We also want to see the health checks we were promised for our children implemented, and proper diagnoses made," she said.
President Xi Jinping demanded a thorough investigation into last year's tainted vaccine scandal at Changchun Changsheng Biotech, and promised severe punishment for those responsible.
But the authorities repeatedly detain, beat, and even "disappear" parent campaigners, who want the government to face up to its responsibilities and give the families hit by faulty vaccines compensation to help with mounting medical bills.
The Changchun incident was only the latest in a string of public health scandals surrounding fake, substandard, and expired vaccines that have had a devastating impact on the health of young children and on their immediate family.
Many parents say they were initially promised compensation and help with medical expenses, but that the assistance never materialized. Many are still seeking redress from similar scandals that occurred years ago.
Reported by Wong Lok-to for RFA's Cantonese Service, and by Gao Feng for the Mandarin Service. Translated and edited by Luisetta Mudie.