Inactivated SARS-CoV-2, Lineage B.1.595_2020 (NY-Wadsworth-33126-01/2020)

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the virus that causes the COVID-19 pandemic, was first identified in Wuhan, China, in late 2019. A member of the Coronaviridae family, it is an enveloped, single-stranded RNA virus characterized by its spike protein (S protein), which enters human cells by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. The virus is primarily transmitted through respiratory droplets and aerosols, causing symptoms ranging from mild respiratory illness to severe pneumonia, multi-organ failure, and even death, particularly in vulnerable populations. Over time, SARS-CoV-2 has undergone continuous mutation, resulting in the emergence of numerous variants with altered transmissibility, virulence, or immune evasion properties. Genomic surveillance is crucial for tracking these variants, which the World Health Organization (WHO) categorizes as variants of concern (VOI), variants of concern (VOC), or variants under surveillance (VUM).

The B.1.595 lineage is a lesser-known SARS-CoV-2 variant first identified in early 2021, primarily in the United States. This lineage possesses a unique set of mutations, including the E484K mutation in the spike protein—a mutation also found in the Beta variant (B.1.351) and the Gamma variant (P.1) and associated with reduced antibody neutralization. Other notable mutations in B.1.595 include D614G (which enhances infectivity) and N501Y (associated with increased ACE2 affinity). Despite these mutations, B.1.595 has not achieved widespread dominance, likely due to competition with more transmissible variants such as the Delta variant (B.1.617.2). Studies suggest that while B.1.595 may exhibit some immune escape, its epidemiological impact remains limited.