diff --git a/bin/join-metadata-and-clades b/bin/join-metadata-and-clades
index f78a1f90..8f28d8b8 100755
--- a/bin/join-metadata-and-clades
+++ b/bin/join-metadata-and-clades
@@ -93,7 +93,6 @@ def main():
     metadata = pd.read_csv(args.metadata, index_col=METADATA_JOIN_COLUMN_NAME,
                            sep='\t', low_memory=False, na_filter = False)
 
-    # Read and rename clade column to be more descriptive
     clades = pd.read_csv(args.nextclade_tsv, index_col=NEXTCLADE_JOIN_COLUMN_NAME,
                          usecols=[NEXTCLADE_JOIN_COLUMN_NAME, *(set(column_map.keys()) - clades_21L_columns)],
                          sep='\t', low_memory=True, dtype="object", na_filter = False) \
@@ -113,7 +112,11 @@ def main():
     # Add clade_legacy column as Nextstrain_clade
     # Use yml mapping
     with open(args.clade_legacy_mapping, 'r') as legacy_mapping_file:
-         clade_legacy_mapping = yaml.safe_load(legacy_mapping_file)
+        clade_legacy_mapping_dict: dict[str, str] = yaml.safe_load(legacy_mapping_file)
+
+    def clade_legacy_mapping(clade_nextstrain: str) -> str:
+        return clade_legacy_mapping_dict.get(clade_nextstrain, f"{clade_nextstrain} Omicron")
+        
     clades["Nextstrain_clade"] = clades["clade_nextstrain"].map(clade_legacy_mapping)
 
     # Remove immune_escape and ace2_binding when clade <21L and not recombinant
diff --git a/defaults/clade-legacy-mapping.yml b/defaults/clade-legacy-mapping.yml
index f43daa4f..12974700 100644
--- a/defaults/clade-legacy-mapping.yml
+++ b/defaults/clade-legacy-mapping.yml
@@ -20,24 +20,4 @@
 21F: 21F (Iota)
 21G: 21G (Lambda)
 21H: 21H (Mu)
-21K: 21K (Omicron)
-21L: 21L (Omicron)
-21M: 21M (Omicron)
-22A: 22A (Omicron)
-22B: 22B (Omicron)
-22C: 22C (Omicron)
-22D: 22D (Omicron)
-22E: 22E (Omicron)
-22F: 22F (Omicron)
-23A: 23A (Omicron)
-23B: 23B (Omicron)
-23C: 23C (Omicron)
-23D: 23D (Omicron)
-23E: 23E (Omicron)
-23F: 23F (Omicron)
-23G: 23G (Omicron)
-23H: 23H (Omicron)
-23I: 23I (Omicron)
-24A: 24A (Omicron)
-24B: 24B (Omicron)
 recombinant: recombinant