Omicron Variant Predominance Study Article  

Citation link

Modes, M. E., Directo, M. P., Melgar, M., Johnson, L. R., Haoshu Yang, Chaudhary, P., Bartolini, S., Kho, N., Noble, P. W., Isonaka, S., & Chen, P. (2022). Clinical Characteristics and Outcomes Among Adults Hospitalized with Laboratory-Confirmed SARS-CoV-2 Infection During Periods of B.1.617.2 (Delta) and B.1.1.529 (Omicron) Variant Predominance—One Hospital, California, July 15-September 23, 2021, and December 21, 2021-January 27, 2022. MMWR: Morbidity & Mortality Weekly Report, 71(6), 217–223. https://doi.org/10.15585/mmwr.mm7106e2 

2.What is the abstract of the article? 

Background:  

The Omicron strain has been reported to be more transmittable and resultant to vaccines disbursed during the Delta Strain predominance. Did the Omicron variant cause an increase in severe illness resulting in higher numbers being admitted to the ICU. One Los Angles hospital created a study from July 2021- September 2021 and December 2021 to January 2022 measuring systematic data obtained from the hospital’s electronic records database. The objective of the experiment was to measure severe illness levels between the two strains. Delta strain was at its prominence until December 2021 until most new infections were Omicron in Mid-December of 2021 making the Omicron strain the predominate strain now. Many people contracting Omicron were among the vaccinated. Twenty percent of young adults admitted to the hospital around this period were submitted for non-covid symptoms. The booster shot has been effective after a person is vaccinated by both vaccines. Many patients with booster shots got few symptoms and didn’t require hospitalizations suggesting booster shots are effective against Omicron strain. 

Methods: 

SARS-CoV-2 infection during periods of Delta and Omicron predominance, clinical characteristics and outcomes were retrospectively abstracted from the electronic health records (EHRs) of adults aged ≥18 years with positive reverse transcription–polymerase chain reaction (RT-PCR) SARS-CoV-2 test results admitted to one academic hospital in Los Angeles, California, during July 15–September 23, 2021 (Delta predominant period, 339 patients) and December 21, 2021–January 27, 2022 (Omicron predominant period, 737 patients). Compared with patients during the period of Delta predominance, a higher proportion of adults admitted during Omicron predominance had received the final dose in a primary COVID-19 vaccination series (were fully vaccinated) (39.6% versus 25.1%) period 

 Results: 

During Delta predominance, the EHR linkage to CAIR did not record booster doses. Fully vaccinated persons hospitalized during Delta predominance were assumed not to have received a booster dose. Among Omicron-period hospitalizations, these severity indicators were compared by four-level vaccination status (unvaccinated, partially vaccinated, fully vaccinated without a booster dose, and fully vaccinated with a booster dose). Patients who remained hospitalized as of January 27, 2022, were excluded from comparisons of death while hospitalized. Demographic and clinical characteristics were also compared between hospitalizations attributed to COVID-19 and those attributed to non-COVID-19 conditions during the early Omicron predominance period. Fisher’s exact tests were used to compare categorical variables and the Mann-Whitney U test was used to compare ordinal or continuous variables. Two-tailed p-values <0.05 were considered statistically significant. All analyses were conducted with R software (version 4.1.2; R Foundation). 

Conclusion: 

In mid-December 2021, the B.1.1.529 (Omicron) variant of SARS-CoV-2, the virus that causes COVID-19, surpassed the B.1.617.2 (Delta) variant as the predominant strain in California.  The quantitative method of data utilized in this study suggest that the Omicron variant is more transmissible and resistant to vaccine neutralization but causes less severe illness compared with previous variants (1–3).  

3.) Was the study experimental or non-experimental? Explain. 

Yes. Quantitative research design was utilized for the study. A sample was extracted from Omicron penitents who had contracted the illness between 12/21/2021 and 11/2022. This was a simple random sample without a control group.  

4.) Was the research qualitative or quantitative? Explain. 

Quantitative research design was utilized throughout this study. Quantitative data was obtained from July 15–September 23, 2021 (Delta predominant period, 339 patients) and December 21, 2021–January 27, 2022 (Omicron predominant period, 737 patients).  

Fisher’s exact tests were used to compare categorical variables and the Mann-Whitney U test was used to compare ordinal or continuous variables. Two-tailed p-values <0.05 were considered statistically significant. All analyses were conducted with R software (version 4.1.2; R Foundation). 

5.) What was the population studied? 

Adult’s 18 years and older with positive reverse transcription–polymerase chain reaction (RT-PCR) SARS-CoV-2 test results admitted to one academic hospital in Los Angeles, California.

6.) What sample was used for this study?

A stratified sample was taken in a Los Angeles, California hospital during July 15–September 23, 2021 (Delta predominant period, 339 patients) and December 21, 2021–January 27, 2022 (Omicron predominant period, 737 patients) 

7.) Method of measurement? 

• Categorical variables and the Mann-Whitney U test was used to compare ordinal or continuous variables.  
• Researchers conducted a Two-tail test  
• compared the test P values  

8.) Methods of analysis. a. If the research was quantitative, what statistical tools were used to analyze the data? 

Several Quantitative analysis tests were conducted during this research study. The researchers utilized a statistical test. Researchers conducted a Two-tail test comparing the test P values. Clinical characteristics and outcomes were retrospectively abstracted from the electronic health records 

9.) What was the conclusion of the study? 

The study concluded that severe illness and admits to the ICU during the dominance of omicron is much less severe than the dominance of the Delta strain (1-3).  

10.) Why is this study useful to you? Explain in detail 

The study was extremely personal to me because I contracted Omicron. I agree with the research designs utilized throughout this study. I found the study to be accurate based on the sample amounts measured and the quantitative calculated data the study produced.   

11.) What would be the next logical step in extending this study? 

The next sensible and logical step would be to continue to conduct this same experiment every time a new dominant strain develops and surprises the previous strain to measure the current vaccinations effectiveness and if booster vaccinations need to be given.