Infectious Diseases

Rapid, high-coverage oseltamivir chemoprophylaxis lowers hospitalization in nursing home influenza outbreaks

This retrospective target trial emulation analyzed 35,086 resident-trial observations across 404 US nursing home influenza outbreaks. Intensive chemoprophylaxis meant oseltamivir for ≥70% of eligible residents within 2 days of outbreak detection. Compared with less-intensive prophylaxis, intensive use reduced 14-day hospitalization risk (RD −0.96%; RR 0.79; 95% CI 0.64–0.96). There was no significant effect on all-cause mortality at 14 or 30 days. 1

Rapidly expanding MDR Ural 4.2.1 TB clade spreads from Russia and Moldova across Europe and Asia

Interrogation of ~200,000 global M. tuberculosis genomes identified a 1,604-strain multidrug-resistant lineage 4.2.1/Ural clade. This clade carries conserved resistance-conferring mutations and is expanding faster than other lineage 4.2.1/Ural clades. Phylogeographic reconstruction points to the Russian Federation as the most likely origin, with multiple exports to European and Asian countries. Its broad dispersal and apparent fitness make it a high-priority MDR-TB threat for regional programs and global TB strategies. 2

MDRmDx GeneXpert-compatible cartridge broadens rifampicin and isoniazid resistance detection from sputum

MDRmDx is a low-complexity nucleic acid amplification assay for 10-color GeneXpert instruments that detects M. tuberculosis plus rifampicin and isoniazid resistance. Analytical limits of detection for M. tuberculosis and rifampicin susceptibility were similar to Xpert MTB/RIF Ultra. MDRmDx identified all rpoB mutations with ≥0.5% global prevalence, including I491F and several not detected by Ultra. In frozen sputum enriched for smear-negative and drug-resistant samples, sensitivity exceeded 90% for M. tuberculosis and was near-perfect for rifampicin and isoniazid resistance. 3

Broad-lineage Lassa virus lateral flow RDT shows markedly improved analytical sensitivity

Investigators developed a lateral flow rapid diagnostic test targeting Lassa virus nucleoprotein using new monoclonal antibody pairs. In 60 human serum and plasma specimens, the final assay demonstrated 100% specificity. It detected multiple genetically diverse Lassa virus strains, though with lineage-dependent sensitivity differences. Compared with the ReLASV Pan-Lassa Antigen Rapid Test, recombinant antigen testing showed ~64-fold higher analytical sensitivity. 4