Summary The SARS-CoV-2 Omicron variant became predominant in the United States in mid-December 2021, coinciding with an increase in hospitalizations associated with SARS-CoV-2. What does this report add? Among adults hospitalized with SARS-CoV-2 infection during Omicron dominance, COVID-19 vaccination, even with a booster dose, was associated with a lower likelihood of intensive care unit admission. Compared with patients during the Delta predominant period, patients in the Omicron period had less severe disease, largely driven by a higher proportion of complete vaccinations. About 20% of early hospitalizations in the Omicron period were for conditions other than COVID-19, particularly among young adults and those vaccinated. What are the implications for public health practice? COVID-19 vaccination, particularly a booster dose, remains critical to mitigating the healthcare burden of the Omicron variant. |
The highly contagious Omicron variant of SARS-CoV-2 became the dominant strain in the United States in mid-December 2021, coinciding with an increase in hospitalizations of COVID-19 patients.
Among those admitted during the omicron surge, vaccinated adults had less severe illness compared to unvaccinated adults and were less likely to end up in intensive care, according to a new study from Cedars-Sinai and the Centers for Disease Control and Prevention. Disease Prevention (CDC).
"Overall, the omicron period group was less likely to be admitted to the intensive care unit (ICU) and were also less likely to require invasive mechanical ventilation compared to the delta period group," said Matthew Modes, MD, pulmonologist. at Cedars-Sinai and co-first author of the paper.
The researchers also found that during the omicron period fewer patients died while hospitalized (4.0%), compared to those admitted when the delta variant was dominant (8.3%).
In a single-hospital study published in the CDC’s Morbidity and Mortality Weekly Report, scientists looked at the characteristics of 339 patients hospitalized with COVID-19 at Cedars-Sinai Medical Center in Los Angeles from July to September 2021. , when the delta variant of SARS-CoV-2 was dominant. They compared that group to 737 patients admitted with COVID-19 between December 2021 and January 2022, when the omicron variant was more common.
Clinical information was collected from the electronic health records of patients in the study and then analyzed by a team of researchers led by Sharon Isonaka, MD, MS, chief value officer and vice president of Clinical Efficiency and Value at Cedars-Sinai.
The analysis revealed that a larger share of patients hospitalized during Omicron were vaccinated compared to patients hospitalized during the summer of 2021 when the delta variant predominated, likely reflecting the higher percentage of populations that were vaccinated during Omicron.
“In addition to the protection that vaccination offered to people admitted to hospital when Omicron was dominant, we saw that adding a booster dose seemed to be particularly important in reducing the severity of the disease, especially among older adults,” said Peter Chen. , MD, senior author of the study and director of Pulmonary and Critical Care Medicine at Cedars-Sinai.
" Unvaccinated patients hospitalized with COVID-19 during the dominance of the Omicron variant still had a higher likelihood of being admitted with severe complications and appeared to be at higher risk of developing respiratory failure, compared with vaccinated patients," Chen said, who holds the position of Medallion Chair in Molecular Medicine and is a professor of Medicine and Biomedical Sciences.
A large number of hospitalizations during the pandemic has strained health systems across the country. Vaccination, including a booster dose for those who are fully vaccinated, remains critical to mitigate the risk of severe disease associated with SARS-CoV-2 infection.
“A clear pattern emerges if you only take patients from the omicron period and compare their vaccination status to the percentage of them who ended up in the ICU. The more vaccinated someone is, from unvaccinated, partially vaccinated, fully vaccinated without a booster dose to fully vaccinated with a booster dose, the better the outcome for the patient,” said Michael Melgar, MD, co-author of the study and co-author of the study. a CDC medical officer.
