This site is automatically updated twice per week with spike protein changes seen in sequences newly submitted to GISAID, displayed in structures divided by the most common clades and color coded for type of changes including if they are part of the receptor binding interface. The latter are of interest because they could alter receptor binding affinity of the virus and viral fitness in principle but most often don't have an effect and so far none of them has been associated with increased clinical severity. Because the same sites are also common epitopes, receptor binding changes could also affect binding to some antibodies and in rare cases partially affect vaccine response but any claims to that would have to be shown experimentally. Besides the new occurrences of changes listed in the main text, receptor binding site changes are also cumulatively reported in the table "List all RBS changes". Strains with a specific spike change can be retrieved from EpiCoV (after login) by selecting or typing the amino acid change in the "variant" drop-down menu for example in the format "Spike_S477N".