The health minister of the central Asian state was fired last week over the case, which has led to the death of four babies, the Kazakh state news agency said on Tuesday.
The children, aged between two months and 10 years old, were infected in recent months in a hospital in the south of the country, apparently after receiving transfusions of blood contaminated with the virus.
The Kazakhstan Today news agency quoted an official from the prosecutor's office as saying that the criminal charges were brought several days ago against the former regional health director, two of his deputies and five doctors.
Police were also investigating forged signatures of six donors who received money for their blood, the agency said.
Health officials have been testing children for the virus near the city of Shymkent.
About 2,000 more children are to be tested in the next few days.