March 26, 2026

RSV

Immunogenicity and Safety of the AS01E-Adjuvanted Respiratory Syncytial Virus (RSV) Prefusion F Protein Vaccine in Adults Aged 18–49 Years at Increased Risk of RSV Disease Compared with Adults Aged ≥60 Years
This open-label, multicountry phase 3b trial included 18–49-year-olds at increased risk (at-risk 18–49 group) and a control group of ≥60-year-olds with or without chronic conditions (≥60 group). Primary objective was to demonstrate immunological noninferiority to adjuvanted RSVPreF3 in the at-risk 18–49 versus ≥60 group, based on group RSV-A/RSV-B geometric mean titer ratios and seroresponse rate differences one month postvaccination. Humoral, cell-mediated immunogenicity, and safety were assessed until six months postvaccination. Overall, 1458 adults were vaccinated. Immunological noninferiority was demonstrated in the at-risk 18–49 versus ≥60 group at one month postvaccination. Both groups showed increased RSV-A/RSV-B neutralizing titers and RSVPreF3-specific CD4+ T-cell frequencies at one month postvaccination that declined but remained above baseline at six months. No surprising issues with adverse events.

COVID: Active Vaccination/Immunity

Association Between COVID-19 Vaccination and Sudden Death in Apparently Healthy Younger Individuals: A Population-based Case-control Study
Background: Despite a lack of strong evidence, concerns have been expressed that COVID-19 vaccination might lead to sudden death in younger healthy adults. These investigators conducted a population-based case-control study using linked administrative datasets of residents of Ontario, Canada. They defined cases as those with out-of-hospital death, or death within 24 hours of presentation to hospital with a final diagnosis of cardiac arrest between April 1, 2021 and June 30, 2023. Study showed vaccination against COVID-19 was not associated with an increased risk of sudden death in people younger than 50 years who had no documented evidence of cardiovascular disease. This finding persisted through sensitivity analyses limited to people aged <40 years, those who died in-hospital with a diagnosis of sudden cardiac arrest within 24 hours of presentation, after exclusion of admissions associated with trauma, mental illness, and substance use, after exclusion of opioid-related deaths, and another sensitivity analysis utilizing a modified SCCS. Collectively, these observations refute the claim that COVID-19 vaccination increases the risk of sudden death.

Applying Machine Learning to Identify Unrecognized COVID-19 Deaths Recorded As Other Causes of Death in the United States
These investigators used machine learning trained on U.S. death certificates from March 2020 to December 2021 to predict 155,536 (95% uncertainty interval: 150,062 to 161,112) unrecognized COVID-19 deaths. This indicates that 19% more COVID-19 deaths occurred in the U.S. than officially reported. They found that predicted unrecognized COVID-19 deaths occurred disproportionately among decedents with less than a high school education; decedents identified as Hispanic, American Indian, Alaska Native, Asian, and/or Black; counties with lower household incomes and worse preexisting health; and counties in the South. These findings suggest that the U.S. death investigation system undercounted COVID-19 deaths unevenly, hiding the true extent of inequities.

Empiric Azithromycin Alters the Upper Respiratory Microbiome and Resistome Without Anti-inflammatory Benefit in COVID-19
Authors start by pointing out that impact of empiric azithromycin use on the respiratory microbiome in patients with viral respiratory infections is unclear. They used longitudinal metatranscriptomics on nasal swabs from a prospective multicentre cohort of 1,164 patients hospitalized for COVID-19. They compared the upper respiratory microbiome, resistome and systemic immune response in patients treated with azithromycin (n = 366) with those who received no antibiotics (n = 474) or other antibiotics (n = 324). They found that azithromycin altered microbiome composition and increased the expression and relative proportion of macrolide/lincosamide/streptogramin (MLS) resistance genes. These changes occurred after one day of exposure and persisted for over a week. Antibiotic resistance gene expression was associated with commensals and potential pathogens, while there were no differences in host inflammatory gene expression in blood and airways. This demonstrates that empiric azithromycin treatment impacts the upper respiratory microbiome and resistome without apparent anti-inflammatory benefit.

COVID-19 mRNA Vaccination in Pregnancy and Risk of Infection in Early Childhood
These results come from a nationwide, register-based cohort study comprising all live-born infants in Norway between March 2021 and December 2023 with follow-up through 2023. Among 146,031 infants born in Norway in the study period, 37,013 (25%) were exposed to COVID-19 vaccination in pregnancy. The offspring’s protection against COVID-19 and the adjusted HRs for hospital contact were 0.48 for the first two months (95% CI, 0.40–0.56), 0.76 at 3 to 5 months (95% CI, 0.60–0.98), 1.13 at 6 to 11 months (95% CI, 0.82–1.56), and 1.14 after 12 months (95% CI, 0.72–1.79). No notable difference in the risk of hospital contacts for infections other than COVID-19 was observed.

COVID: The Late Phase/PASC/Long COVID

Outcomes of Patients with Neurocognitive Symptoms Attending a Long COVID Clinic: A Longitudinal Cohort Study
This is an observational cohort study where they looked at 150 patients with Long COVID and neurocognitive symptoms who completed the PROMIS29 (Patient Reported Outcomes Measurement Information System) inventory at clinic enrollment and six months post-enrollment. These were patients that received care at the Post-COVID Recovery Clinic (PCRC) at the Ohio State University Wexner Medical Center (OSUWMC) between 10/12/2022 and 10/23/2023. All data were extracted from the medical record. The study consisted of a retrospective arm for patients who had already completed six months of treatment at the start date, and a prospective arm for patients who entered the clinic after the start date. They reported statistically significant improvements in all PROMIS29 domains at six months. Clinically significant improvement was seen for physical functioning, fatigue, social functioning, and pain. Improvement were seen in fatigue with symptom-titrated physical rehabilitation, in fatigue and pain with amantadine and memantine, and in sleep disturbance and pain with trazodone and amitriptyline.