China’s drug regulator has identified nine vaccine wholesalers — suspected of filing false reports of the identities of buyers — and said that the further details would be made public later this week, according to Xinhua. The Tuesday report follows the order from China's Food and Drugs Administration asking its local branches in the country to trace the 570 million yuan ($87.83 million) in vaccines that were sold in the black market, to find out where the vaccines ended up and then to release the details publicly.

The wholesalers are based out of six provinces in China and police officials identified them during their investigations, Xinhua reported.

The illegal vaccine ring, which was uncovered in the eastern Shandong province, was made public on Friday. It affected 24 provinces and involved hundreds of people, BBC reported, citing local media. It is believed to have been ongoing since 2011 but details were not made public till Friday.

On Monday, a report about a boy’s death after a vaccination sparked anger among parents and local residents, although officials who are investigating it denied any links of the death to the scandal. The death of the 4-year-old boy happened in the Guangdong province early March, days after he was given meningococcal and polio vaccines, BBC reported.

The arrested ringleaders were allegedly a mother and daughter duo who bought vaccines from licensed and unlicensed sources, and sold them to illegal agents or local disease and prevention centers for higher prices. The duo was detained last April. The nearly $88 million worth of vaccines were not refrigerated properly or transported in approved conditions, compromising them and leading to a possibility of disability or death on consuming them, BBC reported, citing the state-run news agency Xinhua.

About 300 dealers in 24 provinces had allegedly bought the drugs, and the vaccine manufacturers and trading companies were asked to disclose details of their dealings with the suspects by Friday, the South China Morning Post (SCMP) reported. The illegally traded vaccines included those for chicken pox, rabies, meningitis and hepatitis A, and despite being made by licensed manufacturers, they had either expired or were not properly refrigerated.

The vaccines available for children are classified as Category 1, which are free and compulsory, or Category 2, which individuals opt and pay for because they have wider coverage and lower risk. All the vaccines involved in the scandal are category 2, SCMP reported Tuesday.

State authorities knew about the ring since last April but they issued a call to trace the potential victims only on Friday. The delay in taking action on the scandal raised anger among the public.

“This is such a huge case and not a single regulatory official has come out to apologize, not a single one has resigned... this system which doesn't care whether ordinary citizens live or die makes one's soul tired,” a user said on Sina Weibo, the Chinese microblogging site, according to BBC.

Another user said on the same platform, according to BBC: “24 provinces, 5 years already, and how many children!... It's been nearly a year and then they reveal this! Isn't this genocide? Words cannot express how angry I am!”

The latest scandal is the biggest since 2008, when it was found that melamine was being added to milk powder, causing illness in 300,000 people and killing six babies. Last year, Pfizer Inc. closed down its vaccine business in China after its license for its Prevenar vaccine, the only one it sold in the country, was not renewed, Reuters reported. The vaccine is used to provide protecting against pneumococcal disease, which can lead to pneumonia, meningitis and sepsis.