In a study by the Department of Public Health (DPH), the omicron variant BA.2 was revealed to have led to a quick deterioration in health conditions and an increased risk of hospitalizations and deaths in the state of Tamil Nadu in comparison to all other strains. Dr. TS Selvavinayagam, Director of Public Health, stated that several experts thought that omicron caused a mild infection. But when the strain was compared to all other variants, including the delta variant in the study, it was revealed that the omicron variant carried a higher risk of disease and death. He added that severe COVID-19 cases were clustered under the omicron BA.2 variant, predominantly.

The results of the study published in Frontiers in Public Health showed that SARS-CoV-2 viral load, the number of comorbidities, and disease presentations were independently associated with a shorter time to death, especially in patients infected by the BA.2 variant. The study also revealed that 48% of the 287 participants were vaccinated, with 63% of them immunized with Covishield. Also, 6% of the patients were asymptomatic, 30% had mild symptoms, while 47% had a moderate infection, followed by 16% having severe disease. Variant analysis showed that 17.4% of the patients were infected with BA.1. On the other hand, 57.5% were infected with omicron subvariant BA.1.1, followed by 21.9% infected with omicron BA.2. While only 3% of patients were infected with the delta subvariant.

A substantial portion of individuals developed moderate and severe COVID-19 symptoms despite the extension of extensive medical support. He added that another key finding of the study was that the viral load was associated with an increased risk of the development of severe pneumonia and death. The study showed that with every increase in viral load by 1 log, the risk of severe disease hospitalization and death increased by many folds. 

(Source: https://timesofindia.indiatimes.com/city/chennai/tamil-nadu-omicron-ba-2-has-proved-to-be-more-lethal-shows-dph-study/articleshow/94274740.cms)