COVID-19: Challenges of Viral Variants

The COVID-19 pandemic has been accompanied by SARS-CoV-2 evolution and emergence of viral variants that have far exceeded initial expectations. Five major variants of concern (Alpha, Beta, Gamma, Delta, and Omicron) have emerged, each having both unique and overlapping amino acid substitutions that have affected transmissibility, disease severity, and susceptibility to natural or vaccine-induced immune responses and monoclonal antibodies. Several of the more recent variants appear to have evolved properties of immune evasion, particularly in cases of prolonged infection. Tracking of existing variants and surveillance for new variants are critical for an effective pandemic response.

Automated summary

The COVID-19 pandemic has led to unexpected evolution and emergence of SARS-CoV-2 viral variants. Five major variants (Alpha, Beta, Gamma, Delta, and Omicron) have emerged, each with unique and overlapping amino acid substitutions that impact transmissibility, disease severity, and susceptibility to immune responses and monoclonal antibodies. Some recent variants exhibit immune evasion properties, particularly in cases of prolonged infection. Tracking existing variants and surveilling new ones are crucial for effective pandemic response.