RESUMEN
BackgroundOmicron a new variant of SARS COV2 was first detected in November 2021. This was believed to be highly transmissible and evade immunity as a result urgent need was felt to screen all positive, identify Omicron cases and isolate them to prevent spread of infection and study their clinico-epidemiological profile. MethodologyAll positive cases detected in state of Rajasthan during November to January beginning were selected for next generation sequencing. Processing was done as per protocol on Ion Torrent S5 system for 1210 samples and bioinformatics analysis was done. ResultsAmong the 1210 samples tested 762(62.9%) were Delta/Delta like and other lineages, 291(24%) were Omicron and 157(12.9%) were invalid or repeat samples. Within a month the proportion of Delta and other variants was reversed, from zero omicron became 81% and delta and other variants 19%, initially all omicron cases were international travelers and their contacts but soon community transmission was seen. Majority of omicron patients were asymptomatic (56.7%) or had mild disease (33%), 9.2% had moderate symptoms and 2(0.7%) had severe disease requiring hospitalization, of which one (0.3%) died and rest (99.7%) recovered. History of vaccination was seen in 81.1%, of previous infection in 43.2%. Among the Omicron cases BA.1 (62.8%) was the predominant lineage followed by BA.2(23.7%) and B.1.529 (13.4%), however rising trends were seen initially for BA.1 and later for BA.2 also. ConclusionIn very short time Omicron has spread in community and has taken over the preexisting Delta/Delta like and other lineages, it evades immunity, but the good part is most of the cases were asymptomatic or had mild disease and mortality rate was very low.
