Spiking variants Understanding the impact of emerging SARS-CoV-2 variants is essential to inform the development of effective antiviral measures. Studies have indicated that the D614G substitution in the SARS-CoV-2 Spike protein may increase transmissibility, but to what extent this variant has propelled the pandemic is debated. Analyzing thousands of viral genomes together with clinical data, Müller et al. found no evidence that the 614G variant rose in frequency in Washington State mid-2020 due to increased transmissibility or virulence. Instead, the data provided a stronger signal that the surge in 614G was explainable by its repeated introduction into the state as well as local differences in lockdown measures—both human-catalyzed factors.