473. Trends among hospitalized pregnant patients with laboratory-confirmed SARS-CoV-2 — COVID-NET, 14 U.S. States, January 2021–January 2023

BACKGROUND: Pregnant persons are at increased risk for adverse outcomes from COVID-19 infection. We describe trends and clinical outcomes among pregnant patients hospitalized with a positive SARS-CoV-2 test. METHODS: From January 2021–January 2023, hospitalized pregnant patients aged 15–49 years with a positive screening or clinician-directed SARS-CoV-2 test ≤ 14 days prior to or during hospitalization were identified from > 300 hospitals across 99 counties in 14 states in the COVID-19-Associated Hospitalization Surveillance Network (COVID-NET). Trained staff conducted chart abstractions on a representative sample of patients. We examined trends in the proportion of pregnant patients with COVID-19 respiratory symptoms and, among those with respiratory symptoms, trends in demographics and clinical outcomes from January–November 2021 (pre-Omicron), December 2021–June 2022 (early Omicron) and July 2022–January 2023 (later Omicron). Percentages presented were weighted to account for the probability of selection for sampled cases. RESULTS: Out of 1,637 hospitalized pregnant patients with SARS-CoV-2 infection, respiratory symptoms were recorded for 359 (21.9%). The proportion without respiratory symptoms increased from 73.4% (pre-Omicron) to 82.1% (later Omicron). Over the study period, among those with respiratory symptoms, the proportion with ≥1 underlying medical condition increased from 32.7% to 61.5% (Table 1), while the proportion requiring intensive care unit admission or mechanical ventilation decreased from 17.3% to 7.0% and from 7.2% to 0.0%, respectively (Table 2). During the later Omicron period, among patients with respiratory symptoms, 37.8% were unvaccinated, 35.7% had received a primary vaccination series only and 18.7% had received ≥1 booster doses (Table 2); a higher proportion (29.3%) of asymptomatic patients had received ≥1 boosters in the same period (Figure). [Figure: see text] [Figure: see text] CONCLUSION: The proportion of symptomatic pregnant patients hospitalized with COVID-19 who had severe clinical outcomes decreased over time, although adverse clinical outcomes continue to occur. Most symptomatic hospitalized pregnant patients were not up to date with COVID-19 vaccination during a period when COVID-19 booster doses were available. DISCLOSURES: All Authors: No reported disclosures