IFNB1 and COVID-19: In addition, a deletion in the Nsp1-coding region (Δ500–532) resulting in an 11-amino-acid deletion (aa 79 to 89) in the N terminus was found in more than 20% of sequenced samples and in 37 countries worldwide, which is associated with higher reverse transcription-PCR cycle thresholds in SARS-CoV-2 tests and lower serum IFN-β levels in infected patients (30), indicating that the N terminus of Nsp1 not only is essential for the function of Nsp1 but may also play an important role in the viral replication and disease outcome of COVID-19.