The measles vaccine administered to children in Tamil Nadu has been given a clean chit by a government laboratory and human error at the local level could possibly have resulted in the death of four infants last month.

Samples of the vaccine had been sent to the Central Drugs Laboratory at Kasauli in Himachal Pradesh, following the death of the children who had developed complications after receiving the vaccine and died shortly thereafter.

The report, which the laboratory has submitted to the central health ministry, has given a clean chit to the vaccine, saying it is completely safe for use.

The official said the report points to a scenario where human error at the local level while administering the vaccine could have led to the tragedy.

The report will be forwarded to the department of family welfare, which will take further necessary action, including issuing directives to the state government.

Meanwhile, an advanced study called spectroscopy, which could have determined the exact cause of the deaths, is not available at the Kasauli laboratory, sources said.

The Centre had ordered halt to use of the vaccine supplied by a Hyderabad-based company across the country even as the state government suspended the vaccination drive alarmed by the death of the children.

An order of 90 lakh units of vaccine had been placed with the company, which is a wholly owned subsidiary of the National Dairy Development Board, out of which it had supplied 45 lakh units.