MedCram analysis: NB.1.8.1 (Nimbus) spread and interferon-lambda trial evidence

MedCram's expert lecture covers the SARS-CoV-2 Omicron sublineage NB.1.8.1 (Nimbus), first detected in China in January 2025 and listed by WHO as a variant under monitoring, which rose from 2.5% to 10.7% of global sequenced cases by April 2025 and exceeds 40% in Victoria, Australia. It shows higher ACE2 binding affinity and roughly 1.5-1.6-fold reduced neutralization versus LP.8.1, without increased severity. A NEJM randomized trial of nearly 2000 people found a single dose of pegylated interferon-lambda cut 28-day hospitalization or emergency-visit risk by about 50% regardless of vaccination status. The lecture also notes HHS cancelled over $700 million in Moderna H5N1 mRNA vaccine funding.