diff --git a/src/modules/atproto/application/useCases/ProcessFollowFirehoseEventUseCase.ts b/src/modules/atproto/application/useCases/ProcessFollowFirehoseEventUseCase.ts
--- a/src/modules/atproto/application/useCases/ProcessFollowFirehoseEventUseCase.ts
+++ b/src/modules/atproto/application/useCases/ProcessFollowFirehoseEventUseCase.ts
@@ -156,7 +156,7 @@
           return ok(undefined);
         }
 
-        targetId = collectionIdResult.value.toString();
+        targetId = collectionIdResult.value.getStringValue();
       } else {
         if (ENABLE_FIREHOSE_LOGGING) {
           console.warn(
diff --git a/src/modules/atproto/infrastructure/services/DrizzleFirehoseEventDuplicationService.ts b/src/modules/atproto/infrastructure/services/DrizzleFirehoseEventDuplicationService.ts
--- a/src/modules/atproto/infrastructure/services/DrizzleFirehoseEventDuplicationService.ts
+++ b/src/modules/atproto/infrastructure/services/DrizzleFirehoseEventDuplicationService.ts
@@ -101,6 +101,14 @@
           // If a record exists, it hasn't been deleted
           return ok(records.length === 0);
         }
+        case collections.follow: {
+          const followInfoResult =
+            await this.atUriResolver.resolveFollowId(atUri);
+          if (followInfoResult.isErr()) {
+            return err(followInfoResult.error);
+          }
+          return ok(followInfoResult.value === null);
+        }
         default:
           return err(new Error(`Unknown collection type: ${collection}`));
       }