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.

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.§ Initial reports suggest that the Omicron variant is more transmissible and resistant to vaccine neutralization but causes less severe illness compared with previous variants (1-3). To describe characteristics of patients hospitalized with 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%), and fewer received COVID-19-directed therapies. Although fewer required intensive care unit (ICU) admission and invasive mechanical ventilation (IMV), and fewer died while hospitalized during Omicron predominance, there were no significant differences in ICU admission or IMV when stratified by vaccination status. Fewer fully vaccinated Omicron-period patients died while hospitalized (3.4%), compared with Delta-period patients (10.6%). Among Omicron-period patients, vaccination was associated with lower likelihood of ICU admission, and among adults aged ≥65 years, lower likelihood of death while hospitalized. Likelihood of ICU admission and death were lowest among adults who had received a booster dose. Among the first 131 Omicron-period hospitalizations, 19.8% of patients were clinically assessed as admitted for non-COVID-19 conditions. Compared with adults considered likely to have been admitted because of COVID-19, these patients were younger (median age = 38 versus 67 years) and more likely to have received at least one dose of a COVID-19 vaccine (84.6% versus 61.0%). Although 20% of SARS-CoV-2-associated hospitalizations during the period of Omicron predominance might be driven by non-COVID-19 conditions, large numbers of hospitalizations place a strain on health systems. Vaccination, including a booster dose for those who are fully vaccinated, remains critical to minimizing risk for severe health outcomes among adults with SARS-CoV-2 infection.

Tocilizumab treatment in critically ill patients with COVID-19: A retrospective observational study.

OBJECTIVE: Elevated levels of pro-inflammatory cytokines are observed in severe COVID-19 infections, and cytokine storm is associated with disease severity. Tocilizumab, an interleukin-6 receptor antagonist, is used to treat chimeric antigen receptor T cell-induced cytokine release syndrome and may attenuate the dysregulated immune response in COVID-19. We compared outcomes among tocilizumab-treated and non-tocilizumab-treated critically ill COVID-19 patients. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective observational study conducted at a tertiary referral center investigating all patients admitted to the intensive care unit for COVID-19 who had a disposition from the hospital because of death or hospital discharge between March 1 and May 18, 2020 (n = 96). The percentages of death and secondary infections were compared between patients treated with tocilizumab (n = 55) and those who were not (n = 41). MEASUREMENTS AND MAIN RESULTS: More tocilizumab-treated patients required mechanical ventilation (44/55, 80%) compared to non-treated patients (15/41, 37%; P < 0.001). Of 55 patients treated with tocilizumab, 32 (58%) were on mechanical ventilation at the time of administration, and 12 (22%) progressed to mechanical ventilation after treatment. Of patients treated with tocilizumab requiring mechanical ventilation, 30/44 (68%) were intubated within 1 day of administration. Fewer deaths were observed among tocilizumab-treated patients, both in the overall population (15% vs 37%; P = 0.02) and among the subgroup of patients requiring mechanical ventilation (14% vs 60%; P = 0.001). Secondary infections were not different between the 2 groups (tocilizumab: 31%, non-tocilizumab: 17%; P = 0.16) and were predominantly related to invasive devices, such as urinary and central venous catheters. CONCLUSIONS: Tocilizumab treatment was associated with fewer deaths compared to non-treatment despite predominantly being used in patients with more advanced respiratory disease.