Relative Effectiveness and Immunogenicity of Quadrivalent Recombinant Influenza Vaccine Versus Egg-Based Inactivated Influenza Vaccine Among Adults Aged 18-64 Years: Results and Experience From a Randomized, Double-Blind Trial.

Background: Immunogenicity studies suggest that recombinant influenza vaccine (RIV) may provide better protection against influenza than standard-dose inactivated influenza vaccines (SD IIV). This randomized trial evaluated the relative vaccine effectiveness (VE) and immunogenicity of RIV versus SD IIV in frontline workers and students aged 18-64 years.

Methods: Participants were randomized to receive RIV or SD IIV and followed for reverse-transcription polymerase chain reaction (RT-PCR)-confirmed influenza during the 2022-2023 influenza season.

Association between SARS-CoV-2 infections during pregnancy and preterm live birth.

We examined associations between mild or asymptomatic prenatal SARS-CoV-2 infection and preterm live birth in a prospective cohort study. During August 2020-October 2021, pregnant persons were followed with systematic surveillance for RT-PCR or serologically confirmed SARS-CoV-2 infection until pregnancy end. The association between prenatal SARS-CoV-2 infection and preterm birth was assessed using Cox proportional-hazards regression.

Neutralizing Antibody Responses to Messenger RNA Coronavirus Disease 2019 Vaccines Versus Severe Acute Respiratory Syndrome Coronavirus 2 Infection Among Pregnant Women and Vaccine-Induced Antibody Transfer to Infants.

Background: Early coronavirus disease 2019 (COVID-19) vaccine trials excluded pregnant women, resulting in limited data about immunogenicity and maternal-fetal antibody transfer, particularly by gestational timing of vaccination.

Methods: In this multicenter observational immunogenicity study, pregnant and nonpregnant women receiving COVID-19 vaccines were prospectively enrolled. Participants had sera collected before vaccination, at 14-28 days after each vaccine dose, at delivery (umbilical cord and peripheral), and from their infants at 3 and 6 months.

Agreement Between Pregnant Individuals' Self-Report of Coronavirus Disease 2019 (COVID-19) Vaccination and Medical Record Documentation.

For public health research such as vaccine uptake or effectiveness assessments, self-reported coronavirus disease 2019 (COVID-19) vaccination status may be a more efficient measure than verifying vaccination status from medical records if agreement between sources is high. We assessed agreement between self-reported and medical record-documented COVID-19 vaccination status among pregnant individuals followed in a cohort during August 2020-October 2021. At end of pregnancy, participants completed questionnaires about COVID-19 vaccine receipt during pregnancy; staff verified vaccination status using medical records.

Medically Attended Influenza During Pregnancy in the 2019-2020 and 2020-2021 Influenza Seasons.

Influenza testing and case-confirmation rates in pregnant populations have not been reported during the coronavirus disease 2019 (COVID-19) pandemic. Using electronic medical record data from a cohort of nearly 20,000 pregnancies in the United States, this retrospective cohort study examines the frequency of acute respiratory or febrile illness encounters, influenza testing, and influenza positivity during the 2020-2021 influenza season, which occurred during the COVID-19 pandemic, compared with the 2019-2020 influenza season, which largely did not. The ratios of influenza tests to acute respiratory or febrile illness visits were similar in the 2019-2020 and 2020-2021 influenza seasons (approximately 1:8 and 1:9, respectively) but were low and varied by study site.