Comparative 60-day effectiveness of bivalent versus monovalent mRNA vaccines in Shelby County: a population-level analysis.

Background: Two monovalent mRNA vaccines, available in December 2020, were demonstrated to have high efficacy against both the original SARS-CoV-2 strain and variants circulating through the summer and into the fall of 2021. In the context of the Omicron/BA.1 variant, which was predominant from late fall 2021 into winter of 2022 in the United States, and subsequent Omicron subvariants that have been predominant thereafter, vaccine effectiveness of the monovalent mRNA vaccine option is attenuated.

Association Between mRNA Vaccination and Infection From SARS-CoV-2 During the Delta and Omicron BA.1 Waves: A Population-Level Analysis.

Introduction: COVID-19 mRNA vaccine protection against the Omicron variant of SARS-CoV-2 has been shown to be attenuated. Previous research in Shelby County, Tennessee found that vaccine effectiveness might differ by age in the Omicron surge, a finding not reported for other variants. To assess whether patterns in vaccine effectiveness by age group differed on the basis of the predominant strain of SARS-CoV2, we evaluated vaccine effectiveness in Shelby County, Tennessee by age group in the Delta wave and Omicron BA.

Associations Between Breastfeeding and Post-perinatal Infant Deaths in the U.S.

Introduction: Initiation of breastfeeding has been associated with reduced post-perinatal infant mortality. Although most states have initiatives to protect, promote, and support breastfeeding, no analysis of the association between breastfeeding and infant mortality has been conducted at the state and regional levels. To understand the associations between breastfeeding and post-perinatal infant mortality, the initiation of breastfeeding with post-perinatal infant mortality was analyzed by geographic region and individual states within each region.

Real-World Association Between mRNA Vaccination and Infection From the Omicron Strain of SARS-CoV-2: A Population-Level Analysis.

Introduction: Two mRNA vaccines approved in the U.S. have high efficacy against COVID-19 disease from the original strain of SARS-CoV-2.

Breastfeeding and post-perinatal infant deaths in the United States, A national prospective cohort analysis.

Background: Reducing infant mortality is a major public health goal. The potential impact of breastfeeding on infant deaths is not well studied in the United States (US).

Methods: We analyzed linked birth-death certificates for 3,230,500 US births that occurred in 2017, including 6,969 post-perinatal deaths from 7-364 days of age as the primary outcome, further specified as late-neonatal (7-27 days) or post-neonatal (28-364 days) deaths.