Chinese health authorities have launched an investigation after seven infants died following routine hepatitis B vaccinations, state media reported.
Why was this allowed onto the market? The government needs to come clean about this.
State news agency Xinhua said on Monday that four of the seven deaths were in the southern province of Guangdong. The other infants died in the south-central province of Hunan and the south-west province of Sichuan.
All hospitals have been ordered to stop using the vaccine, produced by Shenzhen-based Biokangtai, until the Health Ministry completes its investigation.
The company said in a statement last week, carried by state media, that it rigorously followed safety rules, but was testing the batches suspected of causing the deaths.
China has a history of product safety scandals. In 2008 at least six children died from drinking milk contaminated by the chemical melamine.
Other reports suggest children have died or become ill from faulty encephalitis, hepatitis B and rabies vaccines.
Many people have taken to China's popular microblogging site, Sina Weibo, to call for greater government transparency on health issues.
"Why was this allowed onto the market? The government needs to come clean about this," wrote one Weibo user.
Many Chinese people suspect their government tries to hide bad news about health problems.
In 2003, the government attempted to cover-up the SARS virus outbreak.