Tamil Nadu Public Health Laboratory begins whole genomic sequencing of selected samples

Tamil Nadu Health Department has begun the whole genomic sequencing and testing of cluster cases and random samples at the State Public Health Laboratory, after the formal permissions from the Union Health Ministry was sought recently.

The laboratory was not functioning completely even after the inaugural as the Union Government had to grant formal authorisation for conducting the whole genomic sequencing and other procedures. 

However, after the completion of authorisation process, the whole genomic sequencing of random samples and cluster cases is only being done, say senior officials from Tamil Nadu Health Department.

"The whole genomic sequencing of all the samples is not required and now the testing is more for academic purposes. Currently, 85 percent of the cases are Omicron variant and 15 percent are Delta variant cases. To determine the trend of cases and percentage of the different variant in the total cases, the whole genomic sequencing is being done for major cluster cases, selected cases of international passengers and random sample collection and testing is being done for certain academic research purposes," said health secretary Dr. J Radhakrishnan.

He added that since whole genomic sequencing is not a diagnostic testing and is not mandatory for all the samples as the ICMR guidelines and even the WHO guidelines do not mandate the same. The officials from the Directorate of Public Health and Preventive Medicine say that the laboratory would help if there is a need to conduct whole genomic sequencing, in case of any new variants or re-emergence of any variants, as Delta variant cases are still prevalent. “There is no requirement of whole genomic sequencing for all samples as it is now known well that Omicron variant is common. However, from time to time, the cases can be analysed and the data used as academic evidence,” said Dr P Sampath, joint Director, Directorate of Public Health and Preventive Medicine.