July 25, 2025

RSV

Respiratory Syncytial virus Strain Evolution and Mutations in Western Australia in the Context of Nirsevimab Prophylaxis
During the 2024 RSV season in Western Australia, 21,922 doses of nirsevimab were administered to infants entering their first season, and 1,221 doses to at-risk children. In this context, the selection and spread of escape variants is a potential concern. Investigators performed whole-genome sequencing on 382 clinical RSV samples and 12 wastewater samples collected between September 2023 and October 2024. RSV subtypes, genetic diversity, and mutations within the nirsevimab-binding region of the F protein were analysed. Phylogenetic analysis was conducted to assess lineage dynamics and the potential emergence of escape variants. RSV-A was the dominant subtype (61.8%), with RSV-B accounting for 38.2% of cases. No lineage shifts were observed following nirsevimab introduction and none of the known mutations associated with high-level nirsevimab resistance were detected in either clinical or wastewater samples. The prevalent RSV-B mutation combination (F:I206M:Q209R:S211N) was observed consistently but is not associated with reduced nirsevimab efficacy. Wastewater sampling, covering approximately 2 million people from Perth metropolitan region, confirmed findings from clinical sequences, reinforcing the absence of resistance mutations.

COVID: Active Vaccination/Immunity

Real-world Evaluation of the Effectiveness of Sinopharm COVID-19 Vaccine Against Symptomatic COVID-19 in an Omicron-Dominant Setting in Mozambique: A Test-Negative, Case-Control Study
Authors conducted a study using a prospective cohort follow-up and a nested test-negative design (TND) after a mass vaccination campaign with the Sinopharm vaccine, with an aim of evaluating the effectiveness of two doses of the Sinopharm vaccine in preventing reverse-transcription (RT) polymerase chain reaction (PCR)–confirmed symptomatic SARS-CoV-2 infection. A test-negative case-control study was nested in a community-based enhanced COVID-19 surveillance in seven healthcare facilities including mobile testing stations in the Dondo District, Mozambique, between March 2022 and December 2023. Participants were individuals aged ≥2 years with COVID-19–like symptoms for <10 days. Cases were those with polymerase chain reaction (PCR)–confirmed COVID-19. For each case, three PCR test–negative controls were matched, according to age (±5 years), sex, and date of PCR test (±7 days). Follow-up for all cases was conducted until disease resolution. Vaccine protection was assessed according to the association between complete vaccination and SARS-CoV-2 disease onset ≥14 days after vaccination. The study did not reach the targeted sample size, and only a third were analyzed. A total of 253 cases were matched to 759 test-negative controls by age, sex, and testing date. The adjusted vaccine effectiveness, calculated using matching and adjusted for age and PCR test date, was 18.0% (95% confidence interval, −85.3 to 63.7; P = .63). No COVID-19–positive participants required hospitalization.

COVID: The Late Phase/PASC/Long COVID

Utility of Glucagon-Like-Peptide-1-Receptor Agonists in Mast Cell Activation Syndrome
(For context: Among the phenotypes of Long COVID there is a group that meets criteria for MCAS and responds to MCAS treatments.) Mast cell (MC) activation syndrome (MCAS) is a collection of illnesses rooted in inappropriate MC activation with little to no neoplastic MC proliferation, distinguishing it from mastocytosis. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) engage with GLP-1 receptors present on many types of cells, including MCs. These drugs are already approved for management of a few chronic inflammatory diseases (e.g., diabetes mellitus type 2, obesity, obstructive sleep apnea) but are increasingly being appreciated to help in a wide range of other inflammatory diseases (e.g., Alzheimer’s disease). This is a retrospective case series describing the use of a variety of GLP-1RAs for managing refractory MCAS in a diverse assortment of 47 patients. 47 subjects were selected by the authors from their panels of patients for having been definitively diagnosed with MCAS. Results: Among 47 cases (age range 15-71, 89% female), 89% demonstrated clinical benefit with GLP-1RAs for a broad range of problems associated with MCAS.