Purpose of review: The successes of the coronavirus disease 2019 (COVID-19) mRNA vaccines have accelerated the development of mRNA vaccines against other respiratory pathogens. The aim of this review is to highlight COVID-19 mRNA vaccine advances and provide an update on the progress of mRNA vaccine development against other respiratory pathogens. Recent findings: The COVID-19 mRNA vaccines demonstrated effectiveness in preventing severe COVID-19 and death. H7N9 and H10N8 avian influenza mRNA vaccines have demonstrated safety and immunogenicity in phase 1 clinical trials. Numerous seasonal influenza mRNA vaccines are in phase 1–3 clinical trials. Respiratory syncytial virus (RSV) mRNA vaccines have progressed to phase 2–3 clinical trials in adults and a phase 1 clinical trial in children. A combined human metapneumovirus and parainfluenza-3 mRNA vaccines was found to be well tolerated and immunogenic in a phase 1 trial among adults and trials are being conducted among children. Clinical trials of mRNA vaccines combining antigens from multiple respiratory viruses are underway. Summary: The development of mRNA vaccines against respiratory viruses has progressed rapidly in recent years. Promising vaccine candidates are moving through the clinical development pathway to test their efficacy in preventing disease against respiratory viral pathogens.

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. 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. Sera were collected from a subset of participants before and at 1 and 6 months postvaccination and tested by hemagglutination inhibition for A/H1N1, A/H3N2, B/Yamagata, and B/Victoria and against cell-grown vaccine reference viruses for A/H1N1 and A/H3N2. Overall, 3988 participants were enrolled and vaccinated (25% of the trial sample size goal); RT-PCR–confirmed influenza occurred in 20 of 1963 RIV recipients and 28 of 1964 SD IIV recipients. Relative VE was 29% (95% confidence interval [CI], −26% to 60%). In the immunogenicity substudy (n = 118), the geometric mean titer ratio (GMTR) comparing RIV to SD IIV at 1 month was 2.3 (95% CI, 1.4–3.7) for cell-grown A/H1N1, 2.1 (95% CI, 1.3–3.4) for cell-grown A/H3N2, 1.1 (95% CI, .7–1.6) for B/Victoria, and 1.4 (95% CI, .9–2.0) for B/Yamagata. At 6 months, GMTRs were >1 against A/H1N1, A/H3N2, and B/Yamagata. Relative VE of RIV compared to SD IIV did not reach statistical significance, but RIV elicited more robust humoral immune responses to 2 of 4 vaccine viruses at 1 month and 3 of 4 viruses at 6 months after vaccination, suggesting possible improved and sustained immune protection from RIV. Clinical Trials Registration. NCT05514002.

The standard of care (SOC) for COVID-19 evolved rapidly during 2020 and 2021, but its cumulative effect over time is unclear. In this post hoc analysis of a series of phase 3 trials that evaluated ... Visual Temporal Improvements in COVID-19 Outcomes for Hospitalized Adults. The standard of care (SOC) for COVID-19 evolved rapidly during 2020 and 2021, but its cumulative effect over time... Background: The COVID-19 standard of care (SOC) evolved rapidly during 2020 and 2021, but its cumulative effect over time is unclear. Objective: To evaluate whether recovery and mortality improved ...