More than 130 people have been arrested in connection with the scheme, in which $A63 million worth of illegal vaccines were sold.
At a news conference in Beijing, Senior Communications Advisor with WHO China, Dr Angela Pratt, says there were some issues in the private market that still needed to be solved.
"The problems that have come to light in the last week relate to the distribution of vaccines available for purchase on the private market, and what is now very clear is that there's a need for much stronger management, oversight and monitoring of that part of the supply chain."
The scandal has caused an outcry from worried parents.
