Comparison of Clinical Presentation and Vaccine Effectiveness Among Omicron and Non-omicron SARS Coronavirus-2 Patients

Abstract

The rapidly mutating Omicron SARS-CoV-2 variant has replaced the previous dominant SARS-CoV-2 variants like alpha, and delta resulting in the amplification of coronavirus disease 2019 (COVID-19) cases. The present study was conducted to compare the clinical profile and vaccination status in patients infected with Omicron and non-Omicron SARS-CoV-2 variants. MethodsAll patients who tested positive for coronavirus disease 2019 (COVID-19) during the study period (January 2022 to February 2022) were further tested for detection of SARS-CoV-2 Omicron variant by using Omisure kit (TATA MD CHECK RT-PCR, TATA MEDICAL AND DIAGNOSTICS LIMITED, Tamil Nadu, INDIA). Clinicodemographic factors and vaccination status were compared between both Omicron and non-Omicron groups. ResultsA total of 1,722 patients who tested positive for COVID-19 were included in the study, of which 656 (38.1%) were Omicron and 1,066 (61.9%) were non-Omicron SARS-CoV-2 variants. Blood group and vaccination status were the major predictors for Omicron. The proportion of male patients was 58.4% in the Omicron group and 57.9% in the non-Omicron group. Maximum cases (86.2%) belonged to >18-60 years age group, 7.3% to >60 years age group, and least to 0-18 years (6.5%). The average age of the study participants was 35.4 ± 14.5 years. Vaccinated participants had less chance of having Omicron than the unvaccinated participants (p-value -0.003). Fever and loss of smell were found to be significantly associated with the non-Omicron SARS-CoV-2 variant. (p-value < 0.05). ConclusionThe present study reflects that the clinical course of the disease is milder in Omicron as compared to the non-Omicron variant. However rapid rise in cases can badly affect the healthcare system demanding good preparedness to tackle all the predicaments. Good Vaccination coverage should be of utmost priority irrespective of the variant type.

Genomic epidemiology of severe acute respiratory syndrome coronavirus 2 from Theni, Tamil Nadu

“…Clinical presentation and vaccination status were similar in both suspected Omicron and non-Omicron patients. [ 18 ] This was found to be in agreement with our study. In the study by Raghav et al ,[ 19 ] molecular modeling and docking analysis identified that D614G mutation resulted in the enhanced affinity of Spike S1–S2 hinge region with TMPRSS2 protease, possibly the reason for the increased shedding of S1 domain in G614 as compared to D614.…”

COVID‐19‐Associated Chemosensory Loss Continues to Decline

“…Recent studies have shown changing symptomatology of COVID‐19 infection, with each virus variant “wave” demonstrating varying clinical features 7‐9 . Though considered a disease‐defining symptom, decreasing incidence of olfactory disturbance was demonstrated with data from the powerful N3C database 3 —findings corroborated by subsequent studies using differing means 4,10 .…”

The immune mechanism of the nasal epithelium in COVID-19–related olfactory dysfunction

“…Chest CT findings showed a lower rate of progression and more rapid radiological recovery in OD cases ( 124 ). A previous study indicated that, during the Omicron wave, the clinical course of the disease was milder for the Omicron variant than for non-Omicron variants ( 171 ). The Omicron variant of COVID-19 primarily infects the upper respiratory tract and shows decreased infectivity in the lungs.…”