diff --git a/fastapi_cache/backends/dynamodb.py b/fastapi_cache/backends/dynamodb.py
index ec639d1..7a32e89 100644
--- a/fastapi_cache/backends/dynamodb.py
+++ b/fastapi_cache/backends/dynamodb.py
@@ -1,5 +1,5 @@
 import datetime
-from typing import TYPE_CHECKING, Optional, Tuple
+from typing import TYPE_CHECKING, Optional, Tuple, Union
 
 from aiobotocore.client import AioBaseClient
 from aiobotocore.session import AioSession, get_session
@@ -30,7 +30,7 @@ class DynamoBackend(Backend):
         >> FastAPICache.init(dynamodb)
     """
 
-    client: DynamoDBClient
+    client: Union[DynamoDBClient, None]
     session: AioSession
     table_name: str
     region: Optional[str]
@@ -46,58 +46,63 @@ class DynamoBackend(Backend):
         ).__aenter__()
 
     async def close(self) -> None:
-        self.client = await self.client.__aexit__(None, None, None)
+        if self.client:
+            await self.client.__aexit__(None, None, None)
+            self.client = None
 
     async def get_with_ttl(self, key: str) -> Tuple[int, Optional[bytes]]:
-        response = await self.client.get_item(TableName=self.table_name, Key={"key": {"S": key}})
+        if self.client:
+            response = await self.client.get_item(TableName=self.table_name, Key={"key": {"S": key}})
 
-        if "Item" in response:
-            value = response["Item"].get("value", {}).get("B")
-            ttl = response["Item"].get("ttl", {}).get("N")
+            if "Item" in response:
+                value = response["Item"].get("value", {}).get("B")
+                ttl = response["Item"].get("ttl", {}).get("N")
 
-            if not ttl:
-                return -1, value
+                if not ttl:
+                    return -1, value
 
-            # It's only eventually consistent so we need to check ourselves
-            expire = int(ttl) - int(datetime.datetime.now().timestamp())
-            if expire > 0:
-                return expire, value
+                # It's only eventually consistent so we need to check ourselves
+                expire = int(ttl) - int(datetime.datetime.now().timestamp())
+                if expire > 0:
+                    return expire, value
 
         return 0, None
 
     async def get(self, key: str) -> Optional[bytes]:
-        response = await self.client.get_item(TableName=self.table_name, Key={"key": {"S": key}})
-        if "Item" in response:
-            return response["Item"].get("value", {}).get("B")
+        if self.client:
+            response = await self.client.get_item(TableName=self.table_name, Key={"key": {"S": key}})
+            if "Item" in response:
+                return response["Item"].get("value", {}).get("B")
         return None
 
     async def set(self, key: str, value: bytes, expire: Optional[int] = None) -> None:
-        ttl = (
-            {
-                "ttl": {
-                    "N": str(
-                        int(
-                            (
-                                datetime.datetime.now() + datetime.timedelta(seconds=expire)
-                            ).timestamp()
+        if self.client:
+            ttl = (
+                {
+                    "ttl": {
+                        "N": str(
+                            int(
+                                (
+                                    datetime.datetime.now() + datetime.timedelta(seconds=expire)
+                                ).timestamp()
+                            )
                         )
-                    )
+                    }
                 }
-            }
-            if expire
-            else {}
-        )
+                if expire
+                else {}
+            )
 
-        await self.client.put_item(
-            TableName=self.table_name,
-            Item={
-                **{
-                    "key": {"S": key},
-                    "value": {"B": value},
+            await self.client.put_item(
+                TableName=self.table_name,
+                Item={
+                    **{
+                        "key": {"S": key},
+                        "value": {"B": value},
+                    },
+                    **ttl,
                 },
-                **ttl,
-            },
-        )
+            )
 
     async def clear(self, namespace: Optional[str] = None, key: Optional[str] = None) -> int:
         raise NotImplementedError