Estimation of COVID-19 mRNA Vaccine Effectiveness Against Medically Attended COVID-19 in Pregnancy During Periods of Delta and Omicron Variant Predominance in the United States.

Importance: Pregnant people are at high risk for severe COVID-19 but were excluded from mRNA vaccine trials; data on COVID-19 vaccine effectiveness (VE) are needed. Objective: To evaluate the estimated effectiveness of mRNA vaccination against medically attended COVID-19 among pregnant people during Delta and Omicron predominance. Design, Setting, and Participants: This test-negative, case-control study was conducted from June 2021 to June 2022 in a network of 306 hospitals and 164 emergency department and urgent care (ED/UC) facilities across 10 US states, including 4517 ED/UC encounters and 975 hospitalizations among pregnant people with COVID-19-like illness (CLI) who underwent SARS-CoV-2 molecular testing. Exposures: Two doses (14-149 and ≥150 days prior) and 3 doses (7-119 and ≥120 days prior) of COVID-19 mRNA vaccine (≥1 dose received during pregnancy) vs unvaccinated. Main Outcomes and Measures: Estimated VE against laboratory-confirmed COVID-19-associated ED/UC encounter or hospitalization, based on the adjusted odds ratio (aOR) for prior vaccination; VE was calculated as (1 - aOR) × 100%. Results: Among 4517 eligible CLI-associated ED/UC encounters and 975 hospitalizations, 885 (19.6%) and 334 (34.3%) were SARS-CoV-2 positive, respectively; the median (IQR) patient age was 28 (24-32) years and 31 (26-35) years, 537 (12.0%) and 118 (12.0%) were non-Hispanic Black and 1189 (26.0%) and 240 (25.0%) were Hispanic. During Delta predominance, the estimated VE against COVID-19-associated ED/UC encounters was 84% (95% CI, 69% to 92%) for 2 doses within 14 to 149 days, 75% (95% CI, 5% to 93%) for 2 doses 150 or more days prior, and 81% (95% CI, 30% to 95%) for 3 doses 7 to 119 days prior; estimated VE against COVID-19-associated hospitalization was 99% (95% CI, 96% to 100%), 96% (95% CI, 86% to 99%), and 97% (95% CI, 79% to 100%), respectively. During Omicron predominance, for ED/UC encounters, the estimated VE of 2 doses within 14 to 149 days, 2 doses 150 or more days, 3 doses within 7 to 119 days, and 3 doses 120 or more days prior was 3% (95% CI, -49% to 37%), 42% (95% CI, -16% to 72%), 79% (95% CI, 59% to 89%), and -124% (95% CI, -414% to 2%), respectively; for hospitalization, estimated VE was 86% (95% CI, 41% to 97%), 64% (95% CI, -102% to 93%), 86% (95% CI, 28% to 97%), and -53% (95% CI, -1254% to 83%), respectively. Conclusions and Relevance: In this study, maternal mRNA COVID-19 vaccination, including booster dose, was associated with protection against medically attended COVID-19. VE estimates were higher against COVID-19-associated hospitalization than ED/UC visits and lower against the Omicron variant than the Delta variant. Protection waned over time, particularly during Omicron predominance.

Early trends for SARS-CoV-2 infection in central and north Texas and impact on other circulating respiratory viruses

INTRODUCTION: Rapid diagnosis and isolation are key to containing the quick spread of a pandemic agent like SARS-CoV-2, which has spread globally since its initial outbreak in Wuhan province in China. SARS-CoV-2 is novel and the effect on typically prevalent seasonal viruses is just becoming apparent. We present our initial data on the prevalence of respiratory viruses in the month of March, 2020. METHODS: This is a retrospective cohort study post launching of SARS-CoV-2 testing at Baylor Scott and White Hospital (BSWH), Temple, Texas. Testing for SARS-CoV-2 was performed by real-time RT-PCR assay and results were shared with State public health officials for immediate interventions. RESULTS: More than 3500 tests were performed during the first two weeks of testing for SARS-CoV-2 and identified 168 (4.7%) positive patients. Sixty-two (3.2%) of the 1,912 ambulatory patients and 106 (6.3%) of the 1,659 ED/inpatients tested were positive. The highest rate of infection (6.9%) was seen in patients aged 25-34 years, while the lowest rate of infection was seen among patients aged <25 years old (2%). County-specific patient demographic information was shared with respective public health departments for epidemiological interventions. Incidentally, this study showed that there was a significant decrease in the occurrence of seasonal respiratory virus infections, perhaps due to increased epidemiological awareness about SARS-CoV-2 among the general public, as well as the social distancing measures implemented in response to SARS-CoV-2. Data extracted for BSWH from the CDC's National Respiratory and Enteric Virus Surveillance System (NREVSS) site revealed that Influenza incidence was 8.7% in March 2020, compared to 25% in March 2019. CONCLUSIONS: This study was intended to provide an initial experience of dealing with a pandemic and the role of laboratories in crisis management. This study provided SARS-CoV-2 testing data from ambulatory and inpatient population. Epidemiological interventions depend on timely availability of accurate diagnostic tests and throughput capacity of such systems during large outbreaks like SARS-CoV-2. This article is protected by copyright. All rights reserved.