Who to Boost When: The Effect of Age and Dosing Interval on Delta and Omicron COVID-19 Incidence in the Open-label Phase of the COVE Trial.

Background: To help inform COVID-19 vaccination recommendations, we evaluated the impact of age and dosing interval on clinical benefit of a third dose of mRNA-1273.

Methods: Approximately 17 000 participants from the phase 3 Coronavirus Efficacy trial who previously received 2 doses of 100 µg mRNA-1273 were evaluated for COVID-19 between September 2021 and April 2022 during uptake of a third booster dose of 50 µg of mRNA-1273. Cox models assessed booster relative efficacy of a third dose.

Postnatal Zika and Dengue Infection and their Effects on Neurodevelopment Among Children Living in Rural Guatemala.

Background: Prenatal Zika virus (ZIKV) infection leads to microcephaly and adverse neurodevelopment. The effects of postnatal ZIKV infection on the developing brain are unknown. We assessed the neurodevelopmental outcomes of children exposed postnatally during the ZIKV epidemic.

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.

Next-Generation SARS-CoV-2 Vaccine Formulations and Alternative Routes of Administration.

The development of SARS-CoV-2 next-generation vaccines with the potential for increased effectiveness, durability, breadth, and ability to decrease transmission are of public health importance. We highlight alternative routes of administration of next-generation SARS-CoV-2 vaccines such as mucosal and intradermal administration.

Evaluation of Vancomycin Dose Needed to Achieve 24-Hour Area Under the Concentration-Time Curve to Minimum Inhibitory Concentration Ratio Greater Than or Equal to 400 Using Pharmacometric Approaches in Pediatric Intensive Care Patients.

Objectives: To investigate which independent factor(s) have an impact on the pharmacokinetics of vancomycin in critically ill children, develop an equation to predict the 24-hour area under the concentration-time curve from a trough concentration, and evaluate dosing regimens likely to achieve a 24-hour area under the concentration-time curve to minimum inhibitory concentration ratio (AUC24/MIC) greater than or equal to 400.

Design: Prospective population pharmacokinetic study of vancomycin.

Setting: Critically ill patients in quaternary care PICUs.

Omicron COVID-19 immune correlates analysis of a third dose of mRNA-1273 in the COVE trial.

In the phase 3 Coronavirus Efficacy (COVE) trial (NCT04470427), post-dose two Ancestral Spike-specific binding (bAb) and neutralizing (nAb) antibodies were shown to be correlates of risk (CoR) and of protection against Ancestral-lineage COVID-19 in SARS-CoV-2 naive participants. In the SARS-CoV-2 Omicron era, Omicron subvariants with varying degrees of immune escape now dominate, seropositivity rates are high, and booster doses are administered, raising questions on whether and how these developments affect the bAb and nAb correlates. To address these questions, we assess post-boost BA.

Association Between SARS-CoV-2 Viral Load and COVID-19 Vaccination in 4 Phase 3 Trials.

Coronavirus disease 2019 (COVID-19) vaccines reduce severe disease and mortality and may lessen transmission, measured by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load (VL). Evaluating vaccine associations in VL at COVID-19 diagnosis in 4 phase 3 randomized, placebo-controlled vaccine trials, July 2020 to July 2021, VL reductions were 2.78 log10 copies/mL (95% confidence interval [CI], 1.

Long-term safety and effectiveness of mRNA-1273 vaccine in adults: COVE trial open-label and booster phases.

Primary vaccination with mRNA-1273 (100-µg) was safe and efficacious at preventing coronavirus disease 2019 (COVID-19) in the previously reported, blinded Part A of the phase 3 Coronavirus Efficacy (COVE; NCT04470427) trial in adults (≥18 years) across 99 U.S. sites.

SARS-CoV-2 Viral Load in the Nasopharynx at Time of First Infection Among Unvaccinated Individuals: A Secondary Cross-Protocol Analysis of 4 Randomized Trials.

Importance: SARS-CoV-2 viral load (VL) in the nasopharynx is difficult to quantify and standardize across settings, but it may inform transmission potential and disease severity.

Objective: To characterize VL at COVID-19 diagnosis among previously uninfected and unvaccinated individuals by evaluating the association of demographic and clinical characteristics, viral variant, and trial with VL, as well as the ability of VL to predict severe disease.

Design, Setting, And Participants: This secondary cross-protocol analysis used individual-level data from placebo recipients from 4 harmonized, phase 3 COVID-19 vaccine efficacy trials sponsored by Moderna, AstraZeneca, Janssen, and Novavax.

SARS-CoV-2 RNA and Nucleocapsid Antigen Are Blood Biomarkers Associated With Severe Disease Outcomes That Improve in Response to Remdesivir.

Background: Although antivirals remain important for the treatment COVID-19, methods to assess treatment efficacy are lacking. Here, we investigated the impact of remdesivir on viral dynamics and their contribution to understanding antiviral efficacy in the multicenter Adaptive COVID-19 Treatment Trial 1, which randomized patients to remdesivir or placebo.

Methods: Longitudinal specimens collected during hospitalization from a substudy of 642 patients with COVID-19 were measured for viral RNA (upper respiratory tract and plasma), viral nucleocapsid antigen (serum), and host immunologic markers.

COVID-19 Vaccine Efficacy in Participants With Weakened Immune Systems From 4 Randomized Controlled Trials.

Background: Although the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are highly efficacious at preventing severe disease in the general population, current data are lacking regarding vaccine efficacy (VE) for individuals with mild immunocompromising conditions.

Methods: A post hoc, cross-protocol analysis of participant-level data from the blinded phase of four randomized, placebo-controlled, coronavirus disease 2019 (COVID-19) vaccine phase 3 trials (Moderna, AstraZeneca, Janssen, and Novavax) was performed. We defined a "tempered immune system" (TIS) variable via a consensus panel based on medical history and medications to determine VE against symptomatic and severe COVID-19 cases in TIS participants versus non-TIS individuals starting at 14 days after completion of the primary series through the blinded phase for each of the 4 trials.

A Phase 2 Clinical Trial to Evaluate the Safety, Reactogenicity, and Immunogenicity of Different Prime-Boost Vaccination Schedules of 2013 and 2017 A(H7N9) Inactivated Influenza Virus Vaccines Administered With and Without AS03 Adjuvant in Healthy US Adults.

Introduction: A surge of human influenza A(H7N9) cases began in 2016 in China from an antigenically distinct lineage. Data are needed about the safety and immunogenicity of 2013 and 2017 A(H7N9) inactivated influenza vaccines (IIVs) and the effects of AS03 adjuvant, prime-boost interval, and priming effects of 2013 and 2017 A(H7N9) IIVs.

Methods: Healthy adults (n = 180), ages 19-50 years, were enrolled into this partially blinded, randomized, multicenter phase 2 clinical trial.

Delays in Hepatitis A vaccination in people with HIV in Houston, Texas between 2010 and 2018.

Background: Studies have demonstrated low hepatitis A virus (HAV) vaccination rates among persons with HIV (PWH).

Methods: We conducted a retrospective study of persons entering HIV care at two clinics in Houston, Texas between 2010 and 2018. We defined those eligible for HAV vaccination as those who had no history of HAV vaccination and had a negative anti-HAV IgG at entry to care.

Delays in Hepatitis B Immunization Series Completion in People With Human Immunodeficiency Virus.

Background: Studies have demonstrated low hepatitis B virus (HBV) vaccine series completion among persons with human immunodeficiency virus (HIV).

Methods: We conducted a retrospective record review of persons entering HIV care at 2 clinics in Houston, Texas, between 2010 and 2018. Kaplan-Meier curves summarized time to receipt of HBV vaccines for those eligible for vaccination.

Stochastic interventional approach to assessing immune correlates of protection: Application to the COVE messenger RNA-1273 vaccine trial.

Background: Stochastic interventional vaccine efficacy (SVE) analysis is a new approach to correlate of protection (CoP) analysis of a phase III trial that estimates how vaccine efficacy (VE) would change under hypothetical shifts of an immune marker.

Methods: We applied nonparametric SVE methodology to the COVE trial of messenger RNA-1273 vs placebo to evaluate post-dose 2 pseudovirus neutralizing antibody (nAb) titer against the D614G strain as a CoP against COVID-19. Secondly, we evaluated the ability of these results to predict VE against variants based on shifts of geometric mean titers to variants vs D614G.

Safety and Immunogenicity of a Delayed Heterologous Avian Influenza A(H7N9) Vaccine Boost Following Different Priming Regimens: A Randomized Clinical Trial.

Background: Influenza A (H7N9) has caused multiple disease waves with evidence of strain diversification. Optimal influenza A (H7N9) prime-boost vaccine strategies are unknown.

Methods: We recruited participants who had received monovalent inactivated A/Shanghai/2/2013 (H7N9) vaccine (MIV) approximately 5 years earlier, as follows: MIV with MF59 (MF59 × 2 group), MIV with AS03 (AS03 × 2 group), unadjuvanted MIV (No Adj group), MIV with MF59 or AS03 followed by unadjuvanted MIV (Adjx1 group), and A/H7-naive (unprimed group).

Clinical and Demographic Factors Associated With COVID-19, Severe COVID-19, and SARS-CoV-2 Infection in Adults: A Secondary Cross-Protocol Analysis of 4 Randomized Clinical Trials.

Importance: Current data identifying COVID-19 risk factors lack standardized outcomes and insufficiently control for confounders.

Objective: To identify risk factors associated with COVID-19, severe COVID-19, and SARS-CoV-2 infection.

Design, Setting, And Participants: This secondary cross-protocol analysis included 4 multicenter, international, randomized, blinded, placebo-controlled, COVID-19 vaccine efficacy trials with harmonized protocols established by the COVID-19 Prevention Network.

Immunogenicity of NVX-CoV2373 heterologous boost against SARS-CoV-2 variants.

As part of a multicenter study evaluating homologous and heterologous COVID-19 booster vaccines, we assessed the magnitude, breadth, and short-term durability of binding and pseudovirus-neutralizing antibody (PsVNA) responses following a single booster dose of NVX-CoV2373 in adults primed with either Ad26.COV2.S, mRNA-1273, or BNT162b2 vaccines.

Modifiers of COVID-19 vaccine efficacy: Results from four COVID-19 prevention network efficacy trials.

Questions remain regarding the effect of baseline host and exposure factors on vaccine efficacy (VE) across pathogens and vaccine platforms. We report placebo-controlled data from four Phase 3 COVID-19 trials during the early period of the pandemic. This was a cross-protocol analysis of four randomized, placebo-controlled efficacy trials (Moderna/mRNA1273, AstraZeneca/AZD1222, Janssen/Ad26.