diff --git a/src/adapters/express.ts b/src/adapters/express.ts
index d7c72375..fba2ee3b 100644
--- a/src/adapters/express.ts
+++ b/src/adapters/express.ts
@@ -14,6 +14,6 @@ export const createOpenApiExpressMiddleware = <TRouter extends OpenApiRouter>(
 ) => {
   const openApiHttpHandler = createOpenApiNodeHttpHandler(opts);
   return async (req: Request, res: Response) => {
-    return openApiHttpHandler(req, res);
+    await openApiHttpHandler(req, res);
   };
 };
diff --git a/src/adapters/next.ts b/src/adapters/next.ts
index 4e6a285a..c5df5d7c 100644
--- a/src/adapters/next.ts
+++ b/src/adapters/next.ts
@@ -55,6 +55,6 @@ export const createOpenApiNextHandler = <TRouter extends OpenApiRouter>(
     }
 
     req.url = normalizePath(pathname);
-    return openApiHttpHandler(req, res);
+    await openApiHttpHandler(req, res);
   };
 };
diff --git a/src/adapters/standalone.ts b/src/adapters/standalone.ts
index f4a8eca2..a82b74da 100644
--- a/src/adapters/standalone.ts
+++ b/src/adapters/standalone.ts
@@ -14,6 +14,6 @@ export const createOpenApiHttpHandler = <TRouter extends OpenApiRouter>(
 ) => {
   const openApiHttpHandler = createOpenApiNodeHttpHandler(opts);
   return async (req: IncomingMessage, res: ServerResponse) => {
-    return openApiHttpHandler(req, res);
+    await openApiHttpHandler(req, res);
   };
 };